The attachment of myosin to actin molecules is stimulated by the release of calcium inside the muscle cells. ATP in the muscle provides energy needed to pull the actin filaments inward.
**KEY terms**
Actin are contractile filaments made of protein and found in the cytoskeleton.
Myofibrils are bundles of contractile myofilaments in the skeletal muscle cells.
Myosin is a protein filament found in many cells in the microfilamentous network also in muscle cells.
Sarcomeres are functional units of the muscle cells and ti consists of myosin, actin, and myofilaments.
Sarcoplasmic reticulum of the smooth endoplasmic reticulum of teh skeletal muscle fiber is responsible for storing and releasing calcium ions that are absolutely necessary for muscle contractions.
Schwann cell is a neuroglial cell or supportive cell in the nervous system and it is responsible to the myelin sheath.
Each of the pictures below show the important breakdown levels of a muscles in the body. From the muscle fibers to the cross bridging for contraction. I couldn't get this to post with the rest of the pictures or otherwise they would have been noted under each picture.
When thinking about muscles working together to move an arm, leg, or move the lips to talk I find it amazing. The process that takes place in order to see it happen and how quickly these impulses are processed. It is not as simple as my brain telling my arm to move but it goes much deeper then that. It requires nerve impulses, actin and myosin filaments working together with the proper mixture of ingredients to spark the necessary energies to stimulate muscle contractions. I found it completely amazing to learn the ins and outs of muscles and how they enable us to move our body parts and positions.
Monday, April 14, 2008
Sunday, April 13, 2008
Limb, Neurons, Muscles Lab
Okay so below in the first few pictures is the arm. We were asked to make with an arm with things that we found around the house. Necessity is the mother of invention and that is exactly what you will see going on here.
**Directions on the making of the arm**
1) I took the two bones radius and ulna (knitting needles red and gold) and wired them together
2)Ran a long wire along the side of them.
3)Then took a bit of duct tape and crinkled it into a ball more flattened for the joint or connection area between the bones.
4) Got the silver knitting needle (humerus) and connected them together with wire and alittle bit of tape.
5) Extended the wire along side the humerus this acted as the muscle and my hand was the nerve impulses.
6) Pulled the wire and it made the arm move
7) Oh and artificial arms are not my specialty... haha.
These are the things that I used to make my mechanical arm. A paper hand cut out. Duct tape for the joint. Wire for the muscle movement. Tape to hold it in place. the knitting needles were used for the bones. This was kind of challenging but lots of fun!
**Directions on the making of the arm**
1) I took the two bones radius and ulna (knitting needles red and gold) and wired them together
2)Ran a long wire along the side of them.
3)Then took a bit of duct tape and crinkled it into a ball more flattened for the joint or connection area between the bones.
4) Got the silver knitting needle (humerus) and connected them together with wire and alittle bit of tape.
5) Extended the wire along side the humerus this acted as the muscle and my hand was the nerve impulses.
6) Pulled the wire and it made the arm move
7) Oh and artificial arms are not my specialty... haha.
These are the things that I used to make my mechanical arm. A paper hand cut out. Duct tape for the joint. Wire for the muscle movement. Tape to hold it in place. the knitting needles were used for the bones. This was kind of challenging but lots of fun!
The picture below is of the arm fully extended.
The picture below is of the arm moving to a waving position.
The picture below is of the hand in an upright position. "HEY!!!"
The hand was able to move by pulling on the wire that I had running from the hand along side the bones (radius and ulna the red and gold knitting needles) and through the joint along side the humerus (silver knitting needle). Below is a picture of the upper skeletal body of a human. If you could just focus on the arm that is what I did my lab on. If you look to the left hand side of the diagram you can see the arm that I made form ordinary house hold items. http://en.wikipedia.org/wiki/Arm 
Next we had to make a neuron and its parts. So this is how I did that. The picture in the center is actually what it is suppose to look like. Remember without these little guys we would not be able to move arms, legs, or joints. A neuron is a highly specialized cell that generates and transmits nerve impulses from one part of the body to another. Pretty amazing!
**Key terms**
Synapse is the juncture of two neurons that allows an impulse to travel from one neuron to the next.
Synaptic cleft is a gap between an axon and the dentrite or effector it supplies (muslces or glands)
Receptors are structures that respond to internal or external changes. There are three types of receptors in the body; encapsulated, nonecapsulated (naked nerve endings), and specialized ( like the retina).
Neurotransmitters are chemical substances that are released from the terminal ends of axons when a nerve impulse arrives. This either stimulates or henders the next neuron.
**Supplies and their names or symbolism**
I used color paper cut outs, beads for the neurotransmitters, yarn for the microtubules, wire for the receptors, and hole punches with beads for the synapse vesicles for the different parts.
Below is a picture of synapse.
Below is a picture of synapse.
**Some more key terms**
Dentrites are short highly branched fiber that carries impulses to the nerve of the cell body.
Axon is a long unbranched process attached to the nerve cell body of the neuron that transports nerve impulses away for the cell body.
Myelin sheath is layer of fatty material coating the axons of many neurons in the central and peripheral nervous system.
Node of Ranvier is a small gap in the myelin sheath of an axon it is located between segments formed by schwann cells.
**Picture an supplies and their parts**
The picture above shows an actual neuron. The black dot in the center is actually a big magnet, the nucleus and all the parts surrounding it are the same as what is in a cell microtubules, mitochondria, ribosomes etc... Where the green contruction paper meets with the red is the area of synapse. The red branches are the dentrites. Notice the node of Ranvier and each blue gray piece that is separating it is the myelin sheath and at the end of that "tail" is the axon terminal.
The picture below is that of a muscle and how it is broken down.
http://en.wikipedia.org/wiki/Image:Skeletal_muscle.jpg
http://en.wikipedia.org/wiki/Image:Skeletal_muscle.jpg
Eating N Exercising Working 2gether!
Exercise and eating healthy should go hand in hand. Eating is apart of our daily lives it is necessary to survive and prosper in life. Food is the sustenance that people consume to fill the voids that they might be having in life. For some it consumes them and for others it burdens them. The same thing goes for individual weight gain or loss. We can sit and blame the environment that we have worked so hard to build or the availability for low cost high fat foods but the bottom line is that everyone is in control of what they are consuming whether that is good or bad. I think there are many contributing factors when it comes to weight gain and obesity in America’s society today everything from the dollar menu to the celebration of the good and bad times in the workplace or home life. I don’t think that people want to be unhealthy, after all, there are many people, that each year, have a New year’s resolution that consists of either exercising more, losing weight and/ or to quit smoking, all of which, are along the thought process of getting healthier. I think that the failure to follow through and continue this path of positive thinking is the fact that it is often times too hard to stick to the regimented restrictions. I don’t think that we wake up everyday planning to fail. As a society we are over worked and underpaid. Too tired to take a after dinner stroll or be bothered with prepping the best home cooked meal out of one of those quick and easy cookbooks. It is too easy to pick up drive thru or have something delivered hot and ready to eat. Exercising is the last thing on the check list to do after working all day and doing the whole “parent thing.” We all want to take time for ourselves and relax on the couch. Maybe sip a bit of the liquid relaxer, pop in a movie, or get a few extra zzz‘s. Often times then not you will hear from people who don‘t exercise that they, “don‘t have time for it.” I am not sure if it is they don’t have time for it or if they don’t want to make time for it. What we want and what we need are two different scenerios. A lack of exercise is probably one of the main contributing factors when it comes to thinking about obesity but also food choices are the next. I think another reason for obesity in America today might be the idea that in order to lose weight we have to be on a stringent diet and not only are we torturing ourselves with the idea of exercise and sweat but then we are having our comfort foods taken away at the same time. Many people spend thousands and thousands of dollars on supplements, weight loss videos, appetite suppressants, and gym memberships only to fall short with few lastly results. Exercising for some people is not the number one priority. But unfortunately, it is something that we might need to focus on. Our children look to their parents, family and friends for good role models and examples. So I am sure that the Big Mac with super-sized fries might put a smile on the face of the one buying and eating it but it is frowned upon by our bodies and that is what is paying the price. Paying less for the purchase now but more for it later. Our children are like sponges soaking in all that we do so if we are not exercising or eating right chances are they are not eating doing either. I have noticed that more sports are available for kids in the younger levels. Also, at the schools in this area, at least in the lower levels, they have a weekly walks called “aces” and then kids always look forward to that day. My other son in middle school also has to have two semesters of PE so I am sure that helps in trying to keep kids physically fit. Granted this could be the only exercise that may be getting all day or for the week but at least it is an improvement. I am not sure what is going to jump start America into the idea that healthier is better but harping exercise is obviously not doing it. We know exercise is good for us and that we have to eat all our vegetables to be healthy that is a given. Maybe we need to get our personal lives in order first and prioritize what is important and feed that need before we start feeding anything else. I think that a lack of exercise, an increase in unhappiness and stress are what is contributing to the obesity in today’s America. If you get us our own personal chefs and trainers then we could all be healthy looking like the lastest and greatest of “Muscle and Fitness” models on the front magazine covers.
Friday, April 11, 2008
Show me Your Muscles!
SHOW ME YOUR MUSCLES
This lab has to do with muscle contractions and how fatigue and temperature can effect them. The skeletal muscles are a complex system of coordinated reflexes, constrictions, and neurological impulses. It is something that I take for granted but this lab made me think differently.
MATERIALS:
dishpan of water
narrow strip of paper which will fit around upper arm
ice or snow ( I used ice)
rubber ball & clothespin
timer (stop watch)
Fist Clenching
This lab has to do with muscle contractions and how fatigue and temperature can effect them. The skeletal muscles are a complex system of coordinated reflexes, constrictions, and neurological impulses. It is something that I take for granted but this lab made me think differently.
MATERIALS:
dishpan of water
narrow strip of paper which will fit around upper arm
ice or snow ( I used ice)
rubber ball & clothespin
timer (stop watch)
Fist Clenching
The above picture is me squeezing the ball.
Temperature # of times
Normal 51
Cold 28
The cold temperature of the water caused my hand to stiffen and almost feel numb. It caused my hand to discolor to a really red color. Goodness I did not do well with the cold water.
Stinkin Freezing
Repetitive Muscle Actions
# of Apts___# of secs___# of sqs ball___# of sqs clothes pin
1______________ 20__________49_____________44
2______________ 40__________47_____________44
3______________ 60__________47_____________43
4______________ 80__________46_____________42
5______________ 100_________46_____________42
6______________ 120_________44_____________42
7______________ 140_________42_____________ 41
8______________ 160_________42_____________ 39
9______________ 180_________41_____________ 38
**KEY**
# of apts: number of attempts
# of sqs balls: number of squeezes of ball
# of sqs clothes pins: number of squeezes of clothes pin
While I was doing this test of repetitive muscles reactions my arm began to get sore. I thought that it would tense up in the bicep area but also in my forearm as well. Even my fingers were tired. It seemed to warm up a bit as well.
Another portion of the lab is the part that asks us to place our fingers on our jaw line and see what happens. Place two fingers on the jaw just a bit from the ear and grit your teeth together. When the teeth are not clenched tight the muscle feels normal but when the teeth are gritted together BAM…the muscle pops out. So after doing his part of the lab I went and ate dinner. I felt the same muscles in that area and noticed that it does that every time I chew.
The paper strip that was put around my arm was interesting. I did not have much change in my circumferences though.
Relaxed it was about 15.25 inches
Squeezing my fist it was 15.50 inches
Flexing my Popeye muscle it was about 16 inches
Me flexing! GRRR!
The picture below is of the strip with the measurements of the initial circumference, then after squeezing fist and then flexing.
Okay, so in the picture below you can see me measuring with my thumb and pinkie. The muscle in my arm seemed to be relaxed when the arm was stretched out straight. But once I flexed my muscle it popped up slightly and the muscle was not as stretched out as far.
Before
After
Muscle fibers contain small bundles of contractile filaments. The thick filaments of two proteins myosin and actin. Calcium is released and it stimulates the myosin molecules to the actin molecules and in turn these two work together to cause muscle constriction to take place and then ATP steps in and provides the necessary energy to make it all happen. Nerve impulses are generated in the muscle cells. When the temperature is lowered it inhibits the muscles to properly move at the same speed as they normally would and blood flow is reduced. When the muscles are repetitively used they have a tendency to tire out but with regular exercise they can build endurance which would enable to muscles go for longer.
I was actually surprised at how the water temperature effected my muscles mobility. I would not have thought it would have had such an impact on my endurance levels and abilities.
Leech Lab!
During this lab a leech is used to help us better understand the electrical activities of neurons when we used different stimuli and attach them to the skin. Then dyes are injected into the neurons so that we can better see what they look like and how they respond. With a picture of the steps it gives you a better idea of what was being done during the lab.
*Here are the tools that were used in the experiment*
Feather: Used to give the leech skin a very gentle touch stimulation. It really doesn't need to be a feather, it could be q-tips or something.
Probe: A blunt metal rod attached to a wooden handle useful for lifting, pushing, pressing, moving of specimen. Here you use it to lift tissue, and to push the skin as a stimulus.
Forceps: Fine forceps for very fine manipulations.
Scissors: Good dissecting angled scissors used here to cut open the body wall.
Pins: Stainless steel dissecting pins for pinning tissue to a dissecting dish or board.
Scalpel: For microsurgery, disposable scalpel blades are better and much more economical than the fixed blade scalpel which needs to be sharpened periodically.
Dissection Tray: A tray half-filled with hard wax so that you can stick pins into it to stabilize specimen for dissection.
Leech Tank: Leeches are kept in pond-water (you can actually buy an instant pond-water mix to add to tap water.) If kept in a refrigerator, they can stay happy in it for weeks at a time without feeding.
20% Ethanol: Used to anesthetize the leech. Besides being more humane, it has the added benefit that it stops them from moving, making it easier to pin down the leech.
Leech Tongs: These are basically gross anatomy forceps with blunt tips so that you will not harm the leech as you pick it up.
Dissection Microscope: These are binocular microscopes specifically designed for dissection and other micromanipulations. Essentially, it's a high quality high power magnifying glass. You can clearly see individual cells in a leech's nervous system.
Micromanipulator: A device used to position items with sub-micrometer precision in three dimensions. Here we mount our electrode on it to guide it accurately to a neuron.
Oscilloscope: Basically a sophisticated voltmeter. What you see on the screen is a real time display of voltage (vertical) plotted against time (horizontal). Useful because voltmeters can't track rapidly changing voltages, and even if they could, you couldn't read anything.
Leech: Medicinal leeches are when they are fully extended, they can reach 15 to 20 cm long. When fully contracted, diameter is roughly 1 ~ 2 cm.
*Definitions of terms*
Action Potential: Also known as nerve impulse or spike. One generally talks about a cell "firing" or "generating" an action potential, or simply "spiking." An action potential is a brief change in membrane potential caused by the rapid opening and closing of transmembrane channels that pass specific ions through. Action potentials travel along axons and transfer information over distance. In this virtual lab, action potentials are generated in many of the cells you can find and appear as an almost vertical line superimposed on a horizontal oscilloscope trace. The total number and the rate of firing of action potentials can encode information, as well as the actual shape of the action potential (some are longer lasting than others, as you can see in the lab).
Amplifier: The amplifier stage is omitted in the virtual lab to simplify the controls, but in reality, between the electrode and the oscilloscope, there will be a special amplifier that costs between $500 to $8,000. This amplifier is designed to specifically deal with an electrode that is very high in electrical resistance, but that's another story.
Anterior: A general anatomical orientation term that means towards the front, which is usually defined as the head of the animal. It can be used as "anterior sucker," meaning the forward sucker, or "The brain is anterior to the gut," meaning the brain is toward the front when compared to the gut.
Opposite to posterior.Axon: A type of a thin tube extending from the cell body of a neurons. Axons are distinguished by their specialization to conduct nerve impulses for long distances, normally in a direction away from the cell body. We say "normally" because it's not always the case. In the touch sensitive cells encountered in this virtual lab, the cell bodies are located in the ganglion, but the action potentials are initiated in the body wall and travel towards the cell body. Also, a neuron can have more than one axon. Again, in our touch sensitive cells, there are axons that disappear from the field of view towards the left and right, in the direction of neighboring ganglia. These axons conduct the touch information to different parts of the nervous system, away from the cell body. Brain: The brain of the leech is a rather simple affair. It is essentially a set of specialized ganglia that have fused to become bigger.
Dendrite: A type of thin tube extending from the cell body of a neuron. Dendrites are specialized to receive information from other neurons, and they do not usually conduct action potentials. In the cells featured in this lab, examples of dendrites can be seen as many finer branches near the center of the ganglion. Dendrites do not transmit information for very long distances, but are instead involved in processing the information they receive from other neurons.
Dorsal: Another anatomical orientation term that means towards the top, e.g. "dorsal fin of sharks." In most animals, the top will be the animal's back. It gets a bit complicated in humans and other bipeds because we move perpendicularly to the axis defined by our backs. Opposite to ventral.
Electrode: Electrodes are what you use here to record the activity of the neurons. The generic term "electrode" is defined as a conductor that is used to establish electrical contact with a nonmetallic substance. So an electrode is what one uses to deliver electric shock to the patient's head in electroshock therapy or to the patient's heart in the emergency room. A glass microelectrode is used in our experiment.
Electrolyte: Ionic solution that conducts electricity. Typically, it's created by dissolving some salt. It is used in the real version of our experiment to fill up the glass micorelectrode. The choice of salt and the techniques developed to fill up the electrode are themselves interesting topics, but a little too esoteric perhaps for this lab.
Electrophysiology: The study of life processes and of the physical and chemical processes involved, particularly the electrical aspects.
Fluorescent Dye: A chemical that emits light when it absorbs electromagnetic radiation from another source. It is often used in neurobiology to view one or a selected number of neurons. The problem is that neurons are usually transparent (unless you are studying the gorgeously colored brain of some sea-slugs). This makes them hard to see. The neurons are also usually packed tightly together, which makes them almost impossible to see individually. Scientists have developed a bag of tricks to overcome this problem, and one of these tricks is to inject (or somehow stain) the neurons with fluorescent dyes. By illuminating the neurons with certain frequencies of light or near-light, the dye "lights up," making the study of their shapes and identities.
Ganglion (pl ganglia): A ganglion is a collection of neuronal cell bodies. In the leech, the central nervous system consists of the brain and 21 segmental ganglia connected by the ventral nerve cord. Each ganglion contains 350 neurons, of which 14 respond to touch and pressure.
Lucifer Yellow: A florescent dye that was introduced in 1978. It is based on the chemical luciferin discovered in 1888 that is present in luminescent organisms such as fireflies. It has proven to be a fiendishly useful product with many applications. In this experiment, it is used in a dissolved form and injected into a neuron, but it has also been used with good effect for immunohistochemistry. Lucifer Yellow fluoresces with bright yellow-green color when stimulated with ultraviolet (wavelength 280 nm) or blue (wavelength 430 nm) light. Because of this, to view the fluorescence, you need an expensive halogen or mercury high-pressure lamp and appropriate filters to block out UV, which can damage your eye.
Microelectrode: An electrode that is very very small. It can be made from a coated tungsten metal or other metal under special fabrication techniques, but in this lab, we use a glass microelectrode. A glass microelectrode is made with a specialized "electrode puller" that heats up the middle of a fine glass tube (usually about 1 mm diameter and about 10 cm in length) and pulls two ends of it apart at high velocity with or without rapid cooling. The result is two electrodes, each with a very fine tip, down to smaller than 0.1 µm depending on the settings on the machine.
Morphology: The form and structure of an organism or any of its parts. Here it is the shape of the neuron. It also refers to the branch of biology that deals in such matters.
Nerve Cord: This is basically a bundle of nerve fibers that connects the ganglia located in each segment to one another and to the brain. In the leech, the nerve cord is located ventrally. It is the leech equivalent of the human spinal cord.
Neuroanatomy: The study of the anatomy of neurons or the nervous system.
Neuron: A nerve cell.
Neurophysiology: A study of the physical and chemical processes of neurons.
Posterior: Opposite to anterior at the rear. Resting Potential: The voltage of a cell at rest.
Segment: The leech is a segmental animal like a caterpillar or an earthworm. Its body is made up of repeating similar units.
Sinus: The circulation system of the leech is a little bizarre. I mean who's ever heard of an animal that sticks its nervous system inside itse blood vessels?? Yet that's exactly how it is. The ventral sinus of the leech is made of a tough fibrous material that appears dark green.
Skin: For convenience, we sometimes use the term "skin" in this lab. But the proper term is "body wall," which is a heavily muscled structure that allows the leech to extend or contract at will.
Ventral: Opposite to dorsal at the bottom.
*Questions from lab*
1. What is the electrode measuring?
Electrodes are what you use here to record the activity of the neurons. The generic term "electrode" is defined as a conductor that is used to establish electrical contact with a nonmetallic substance.
2. Why use leeches in neurophysiology experiments?
Leeches belong to the phylum annelida (worm). The nervous system of the leech consists of the brain, the ventral nerve cord, and ganglia that are located in each segment along the nerve cord. The medicinal leech has 21 segmental ganglia, each containing 175 pairs of neurons. The relatively small number and the large size of the neurons have made leeches favorite subjects of neurobiologists. Most people don’t really care about what happens with a leech and they their neurons are easily accessible.
3. What is the difference between a sensory and a motor neuron.
A sensory neuron by definition is are unipolar nerve cells within the nervous system responsible for converting external stimuli from the organism's environment into internal electrical motor reflex loops and several forms of involuntary behavior, including pain avoidance. In humans, such reflex circuits are commonly located in the spinal cord. Below is a picture of a sensory neuron and its parts.
In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system (CNS) that projects their axons outside the CNS and directly or indirectly control muscles. http://wikipedia.org/ Below is a picture of a motor neuron. The website is for both pictures of the neurons.
In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system (CNS) that projects their axons outside the CNS and directly or indirectly control muscles. http://wikipedia.org/ Below is a picture of a motor neuron. The website is for both pictures of the neurons.4. Do you think a leech experiences pain? What is pain?
The leech does not experience pain because it is anestisized. Pain is anything that hurts and no that is not a webster's dictionary definition.
5. What were the two most interesting things about doing this lab?
I did not realize that leeches breathe through there skin and how complex they appear to be inside. I thought it was pretty cool to see the way the different stimulus stimulated the neurons.
6. Anything you found confusing or didn't like about the lab?
No I thought it was pretty self explanatory.
*Procedures*
1. anestisize and desect the leech
2. pin it down in dessection pan and then remove the innards ganglion of the leech
3. cut out ganglion window
4. isolate one ganglion
5. cut the ganglion sinus
6. probe and identify the ganglion sensory cells
7. then pick up each tool and test the cells response
8. then match the cell types!
Above are the different cell types that you can choice from to match up.
This is a picture of the different stimuli that I used and I identified the cell type right.Sunday, April 6, 2008
Table of Contents & Compendium Reviews I & II
Table Of Contents
The Body
Environmental Interactions
Chapters 13 & 14
Compendium Review I
I. Principles of Endocrinology
A. Target Cells, Tropic, Nontropic hormones, & Negative feedback
B. Pituitary & Hypothalamus www.mednote.co.kr
http://faculty.virginia.edu/bio202/lectures/Pituitary.gif
1. Hormones & functions
C. The Thyroid gland www.fccj.org
1. Thyroxine, Triidothyronine, Calcitonin
D. The Parathyroid glands & Pancreas
1. Glucagon & Insulin
2. Adrenal Medulla & Adrenal Cortex www.valleyhealth.com/images/image_popup/adrenal.jpg
3. Diseases of the Adrenal Cortex
E. Endocrine Disorders
II. The Immune System
A. Viruses & Bacteria
1. Treatments for Infections
B. First & Second Lines of Defense
1. Inflammatory Response
2. Pyrogens, Interferons, & Complement
C. Third Line of Defense
1. Antigens
2. T cells, B cells & Antibodies http://www.asu.edu/, http://www.uccs.edu/~rmelamed/MicroFall2002/Chapter%2017/B-Cells.jpg
3. Macrophages, active & Passive Immunity biomed.brown.edu
4. Tissue transplantation
D. Diseases of the Immunity System
1. Allergies www.personalmd.com
2. Autoimmune Diseases
The endocrine system is very complex that is made up of many small glands that are in various places in the body that produces hormones that are transported throughout the body via the bloodstream. Hormones effect our homeostasis, growth & development, reproduction, energy production and storage and behavior.
-The target cells contain receptors that are for specific hormones. Some receptors are found in the cells cytoplasm, or in the cells plasma membrane.
Hormones fall into two very broad categories.
-Tropic hormones stimulate the endocrine glands to produce and release hormones.
-Nontropic hormones are needed to help stimulate cell growth, metabolism, and other functions.
Chemical compositions are important when talking about hormones and their classification. There are three types of hormones that are made in the body and they are; steroids, proteins and polypeptides, and lastly, amines.
-There are two types of feedback loops that controls hormonal secretions in the body and they are negative feedback loops and positive feedback loops.
-The pituitary gland secretes hormones by the anterior and posterior lobes. It is pea shaped and hangs from the hypothalamus. The hypothalamus which is located in the brain controls and regulates the hormone production, nutrients and ions in the blood. When talking about the hypothalamus it is important to remember that it produces two types of hormones and they are the inhibiting and releasing hormones. The hypothalamus is triggered to produce the hormones by nerve impulses and chemical stimuli in the body. Below is a picture of the pituitary gland and the hypothalamus and how they cooperate with each other.
The Body
Environmental Interactions
Chapters 13 & 14
Compendium Review I
I. Principles of Endocrinology
A. Target Cells, Tropic, Nontropic hormones, & Negative feedback
B. Pituitary & Hypothalamus www.mednote.co.kr
http://faculty.virginia.edu/bio202/lectures/Pituitary.gif
1. Hormones & functions
C. The Thyroid gland www.fccj.org
1. Thyroxine, Triidothyronine, Calcitonin
D. The Parathyroid glands & Pancreas
1. Glucagon & Insulin
2. Adrenal Medulla & Adrenal Cortex www.valleyhealth.com/images/image_popup/adrenal.jpg
3. Diseases of the Adrenal Cortex
E. Endocrine Disorders
II. The Immune System
A. Viruses & Bacteria
1. Treatments for Infections
B. First & Second Lines of Defense
1. Inflammatory Response
2. Pyrogens, Interferons, & Complement
C. Third Line of Defense
1. Antigens
2. T cells, B cells & Antibodies http://www.asu.edu/, http://www.uccs.edu/~rmelamed/MicroFall2002/Chapter%2017/B-Cells.jpg
3. Macrophages, active & Passive Immunity biomed.brown.edu
4. Tissue transplantation
D. Diseases of the Immunity System
1. Allergies www.personalmd.com
2. Autoimmune Diseases
The endocrine system is very complex that is made up of many small glands that are in various places in the body that produces hormones that are transported throughout the body via the bloodstream. Hormones effect our homeostasis, growth & development, reproduction, energy production and storage and behavior.
-The target cells contain receptors that are for specific hormones. Some receptors are found in the cells cytoplasm, or in the cells plasma membrane.
Hormones fall into two very broad categories.
-Tropic hormones stimulate the endocrine glands to produce and release hormones.
-Nontropic hormones are needed to help stimulate cell growth, metabolism, and other functions.
Chemical compositions are important when talking about hormones and their classification. There are three types of hormones that are made in the body and they are; steroids, proteins and polypeptides, and lastly, amines.
-There are two types of feedback loops that controls hormonal secretions in the body and they are negative feedback loops and positive feedback loops.
-The pituitary gland secretes hormones by the anterior and posterior lobes. It is pea shaped and hangs from the hypothalamus. The hypothalamus which is located in the brain controls and regulates the hormone production, nutrients and ions in the blood. When talking about the hypothalamus it is important to remember that it produces two types of hormones and they are the inhibiting and releasing hormones. The hypothalamus is triggered to produce the hormones by nerve impulses and chemical stimuli in the body. Below is a picture of the pituitary gland and the hypothalamus and how they cooperate with each other.
-Anterior Pituitary is in charge of the following hormones:
Growth hormone: breaks down fat in the body, growth in cells, muscles, and bones
Thyroid-stimulating hormone: releases throxine & triiodothyronine.
Andrenocorticotropic hormone: where hormones are secreted by the adrenal cortex and glucocorticoids.
Gonadotropins: gamete and hormone production takes place by the gonads.
Prolactin: stimulates milk production
Melanocyte-stimulating hormone: unknown the function of this hormone. How could we not know this?
-Posterior pituitary gland is in charge of the following hormones:
Antidiuretic hormone: which stimulates water reabsorption by nephrons of the kidney.
Oxytocin: stimulates the release of milk from breasts and contractions during birth.
-The thyroid gland is in the neck and it produces three different hormones. Depending on the person each thyroid is shaped differently wither U-shaped or H-shaped. The thyroid is important in balancing out the metabolism, heat production, and calcium levels in the blood. The thyroid gland is made up of a spherical shaped structure known as the follicles.
-The two hormones, thyroxin and triiodothyronine work together to accelerate the breakdown of glucose and also assist in the growth and development. Calcitonin decreases the elevations of calcium in the blood.
When thyroid activity is slowed down it is called hypothroidism and when it is increased it is called hyperthyroidism.
-Parathyroid glands are embedded into the back of the thyroid gland and they produce the hormone Para hormone. Its co-worker is calcitonin and when they work together it makes for a successful calcium level drop.
- The pancreas’ primary function is to produce insulin and glucagons that will control the glucose levels in the blood but it also produces digestive enzymes that it releases into the small intestine. It is located in the abdominal cavity. Below is a picture of the pancreas and a portion of the small intestine.
-Glucagon raises the glucose levels in the blood and directly goes against the actions of insulin. Insulin causes the blood sugar levels to drop after eating food. There are tests that can be conducted that help with finding out if the levels are balanced in the body it is called the glucose tolerance test. During this test the doctors give their patients glucose orally and then check the blood levels regularly.
The adrenal glands sit on top of the kidneys and each is made up of two parts.
-The adrenal medulla which is what raises your heart rate and accelerates the breathing when we get frightened or scared from the latest freaky movie at the theater. It produces our stress hormones called adrenaline and noradrenaline. This is what determines whether you are going to stay and fight or take flight. This is a picture of the kidneys with the adrenal glands nestled into the upper portion of them.
-The adrenal cortex produces three types of hormones and it is considered to be the outer part of the gland. The first group is called the glucocorticoids which are important in glucose metabolism and maintaining blood glucose levels. Several chemically secreted glucocorticoids are important and one of those is cortisol. Cortisol helps in the inflammation of the tissues when they are injured or damaged. The second group is called the mineral corticoids and they are involved in electrolyte or mineral salt balance. The most important one is aldosterone. It stimulates sodium reabsorption in sweat glands, saliva, and potassium excretion of the kidneys. Aldosterone helps to conserve body water.
-Endocrine disorders and their causes-
Hypersecretion = over production of something hyposecretion = under production of something
Giantism: hypersecretion of growth hormones (GH) starting at birth or early on in life.
Dwarfism: hyposecretion of growth hormone starting at birth or early on in life.
Acromegaly: hyper secretion of GH after bone growth has stopped
Hyperthyroidism: over activity of the thyroid gland
Hypothyroidism: under activity of thyroid gland
Hyperparathyroidism: excess parathyroid hormone secretion usually resulting from a benign tumor in the parathyroid gland.
Cushing’s syndrome: hyper secretion of hormones from adrenal cortex or from cortisone treatments
Hyporparathyroidism: hyposecretion of the parathyroid glands
Diabetes insipidus: hyposecretion of ADH
Diabetes mellitus: insufficient insulin production or inability of target cells to respond to insulin
Addison’s disease: gradual decrease in production of hormones from adrenal gland very common with that of an autoimmune reaction.
The immune system is a complex system in our body. It is what is necessary to fight off infections, viruses, and bacteria.
-Viruses are nonliving biological agents that invade cells. A virus has a nucleic core that consists of DNA or RNA. It contains a protein that is in the core that is known as a capsid. Viruses can’t multiply and divide on their own like cells can. A viruses main mission is to invade and conquer. Most viruses get into the body through the respiratory and digestive systems and also through sexual contact.
When an invasion like this takes place the immune system kicks into high gear usually wiping out the virus within 10 to 14 days.
-When we think of bacteria it is not always thought that there are good and bad bacteria but some bacteria are helpful to the body and others can be harmful. Bacteria are classified as living organisms that take over their hosts. Bacteria are prokaryotes. (no nucleus) Bacteria contains tiny circular chromosomal DNA called plasmids. Bacteria can enter into the body through the respiratory, upper GI tract, cuts and abrasions, and urinary system. Once they are inside the body they often use our own nutrients to make more their kind.
Treating viruses and bacteria they have to be treated differently. Bacteria can be combated with antibiotics by shutting down the protein synthesis.
-The first line of defense is a physical and chemical barrier. The skin is an important physical barrier in defending the body against foreign microorganisms. There is a layer of the skin called the dermis. It has epidermal cells are produced by cell division in the epidermis. The dead cells contain keratin. Keratin is what is used in waterproofing our bodies and providing protection for the tissues. The cells of the epidermis are joined by special structures known as tight junctions. The chemical barrier in the first line of defense is the hydrochloric acid that the stomach produces and that aids in destroying the bacteria that is ingested. Tears and saliva are contain the enzyme lysozyme which are used in destroying the cell wall of the bacteria.
-The second line of defense combats infectious agents that might get through the first lines of defense and it involves a huge array of chemical and cellular agents. There are four components in the second line of defense; inflammatory response, pyrogens, interferons, and complement.
Pyrogens are molecules released primarily by macrophages that have been exposed to bacteria. The pyrogens travel to the hypothalamus. The body’s temperature is controlled by a group of nerve cells kind of like an internal thermometer. Below is a picture of a macrophage attacking foreign cells. 
Interferons are a group of proteins that are released from cells that are infected by the virus. Interferons don’t protect the cells that are already infected by the different viruses they just help in stopping the spread of the viruses to other cells.
Blood proteins come together to give help to the antibodies to form what is called the complement system.
There are five proteins that join together to form a large protein complex called the membrane-attack complex. This membrane gets inside the plasma membrane of the cell and makes an opening for water to flow through. This in turn causes the bacteria to swell up and explode.
-The third line of defense is the immune system. The cells of the immune system selectively target foreign substances and foreign organisms. The immune system is extremely important in maintaining homeostasis by eliminating bacteria, viruses, single celled fungi and many parasites. The immune system is like the paper sorter of the body. Separating the good stuff from the bad stuff.
-Antigens are substances that trigger the immune response. Antigens stimulate two types of lymphocytes which are T cells and B cells.
-B cells react to microorganisms called bacteria toxins. When activated they produce antibodies. These cells mature in the bone marrow. Below is a picture of a T cell and its immune defense.
-T cells are formed in the thymus and each one will bind with another antigen.
Several million of the B & T cells are produced in the body early in life. Only a small percentage of these cells will be called into action during our lifetime. There are four types of that are important when thinking about T cells.
1. Cytotoxic T cells bind to the molecules in the membranes of the cells they attack and then they release a chemical substance known as perforin-1. These guys are housed in the membranous sacs in the cytoplasm of the cytotoxic T cells. The performing-1 are then released into the space between the killer cell and its prey.
2. Helper T-cells enhance the immune response and it releases interleukin 2 and this helps in increasing the activity of the cytotoxic T cells. These cells make up about 60% to 70% of the T cells that are moving around throughout the body.
3. Memory T cells are also produced when antigens are present. These guys form a cellular reserve and they protect the body in the event that the intrusion occurs at a later date.
4. Suppressor T cells are the cells that turn off the actions of the immune system. As the job of the other T cells begin to slow down and the suppressor T cells begin to increase.
Below is a picture of a B cell. It is interesting to see its way of responding.
-Antibodies are formed by the B cells dividing into what is known as lymphoblasts and then they work together to form a new cell called the plasma cell. Then these cells produce antibodies. Antibodies are proteins that get rid of bacteria and bacteria toxins. Antibodies fall into a class of blood proteins called globulins and they are specifically called immunoglobulins. It is T shaped and has four peptide chains.
When an antigen enters into the body it initiates a primary response and this response is pretty slow but effective. Antibodies kill of antigens different ways.
1. By neutralization and this where the antibodies bind to viruses or bacterial toxins by putting a clear coat around them.
2. Agglutination this occurs when antibodies bind to the antigens and clump together.
-Macrophages play a very important role in protecting the body. They help stimulate T and B cells to fight off bacteria toxins. The macrophages are the ones that cover the foreign toxins surround them and clump together and present them to the help T cells.
- There are two types of immunity that take place in the body.
One type is active immunity. Vaccines are considered to be an active immunity. Reason being is because the vaccine is injected into the patient and then the body produces memory cells in T and B cells that protect the body against futuristic infections. Vaccines has helped in combating serious diseases such as polio, and smallpox.
Another type of immunity is passive immunity. It is a temporary form of protection where the body is injected with immunoglobulins. The cells in the body are not activated and that is why it is considered passive. An example of this would be the injection of immunoglobulins after a poisonous snake bite. Infants can also get this type of protection through the placental sac while in the womb.
-Tissue transplants are very complicated for the immune system. There are three ways that tissue transplantation can be excepted. The first way is if you can actually use what you already have. An example of this would be with burn victims a lot of times the doctors will use tissue from other areas of the body cover a very damaged area. The second way is if the tissue that is being used comes from an identical twin. Because the twins have identical antigens and cells. The last way a tissue transplant may be excepted is if medication (immunity suppressant) is given to the patient. This medicine is usually continued throughout the lifetime of the patient. Unfortunately, this causes the patient to be vulnerable to many other viruses and bacteria in the environment.
When talking about the immune system you have to keep in mind that with every complex system in the body there can be malfunction. Two types of malfunction are autoimmune diseases as well as allergies. I did not realize that allergies were a malfunction of the immune system. Boy there is a lot of malfunctioning going on! Below is a picture of the way histamines are released and worked.
-Allergies are the body’s way of overreacting to environmental substances. Antigens that stimulate an allergic reaction are called allergens. Histamines cause the arterioles to dilate and then the bronchioles constrict which makes it hard for the person to breathe. When this happens it is called asthma. Most allergic reactions are not life threatening but if the allergic response occurs in the blood stream then it can be fatal if not treated right away. A drop in blood pressure and constriction of the bronchioles can result in anaphylactic shock. I have heard of this happening with bee stings and snake bites. Allergies can be treated three different way. The first way is easy stay away from what bothers. Second, administer antihistimines which counteract the effects of the body. Third, get allergy shots. With each shot that is given the level of the allergen is increased and by doing this it helps in reducing the body’s allergic reaction.
-Autoimmune diseases result from the body calling an attack on its own cells. This can take place in a number of ways. One way is if a body organ is injured in some way and then the normal body proteins are entered into the blood stream this then results in a immune system response. Also, a genetic or chemical mutation that the body no longer recognizes as belonging to the individual.
The immune system is a complex system made up of crime fighters and pacifiers. We all hold a little bit of good and evil when it comes to fighting off infections and diseases or excepting tissues and vaccines. Even sometimes we can have the dramatic consequences of mutiny. Like with each system in the human body they all come with the abilities to malfunction, which in turn can lead to serious consequences. Without this protective big brother, called the immune system, we would be lost in a world of sickness.
Table Of Contents
The Body
Environmental Interactions
Chapters 11 & 12
Compendium Review II
I. Senses
A. General & Special Senses
1. Naked Nerve Endings & Encapsulated Receptors www.visualsunlimited.com
B. Taste & Smell
1. Olfactory Epithelium
library.thinkquest.org
C. The Visual Sense : The Eye
1. Structures & Functions of the Eye www.emedicinehealth.com
2. Cones & Rods
3. Visual Problems
D. Hearing & Balance
1. Anatomy of the Ear
2. Structures & Functions of the Ear http://www.music.sc.edu/fs/bain/vc/musc726a/MUSC%20726%20Lecture/more%20ear-brain/01-ear.gif
II. The Skeleton & Muscles
A. Structure & Function of the Human Skeleton
1. Compact, Spongy Bones, & Joints bioweb.wku.edu
2. Injuries of Joints http://www.dropmachine.com/media/data/500/AC_JOINTS_BILAT_0001.jpg
B. Skeletal Muscles
1. Muscle Fibers Parts & Functions http://www.muscleandstrength.com/images/articles/musclefiber.jpg
The body has its own surveillance system. There are many receptors in the body that monitor all the things inside the body as well as outside of the body. The body contains two types of receptors that are made up of general senses and special senses. General senses are usually evoked by stimuli. When talking about general they consist of pain, touch, pressures, temperatures and limb positions. When talking about the special senses they consist of taste, smell, vision, hearing and balance. Receptors come in different sizes and shapes. All these senses working together give our body the ability to perceive the environment and our surroundings.
-The receptors for the general senses fall into two categories.
The first one is called the naked nerve ending receptors.
These nerve endings can detect pain, temperature, and light touching. There are two types of pain and they are called somatic and visceral.
Somatic pain is a result of injuries in the skin, joints, muscles and tendons. The response can be a result of many types of injuries that may occur such as pinching, cutting, breaking, crushing, or even hot and cold temperatures.
Visceral pain is a result from the stimulation of naked nerve endings in the body organs (viscera). Pain receptors are often stimulated by expansion. For example, pain in the intestinal track might be caused by gas stretching the naked nerve fibers in the walls of the intestines. In other body organs the pain receptors could be caused by a lack of oxygen. Somatic pain is easily identified (pinching) whereas visceral pain is often vague and hard to localize (chest pain is it the lungs, heart?) Visceral pain that appears on the body surface but away from the actual location of the pain is called referred pain. Below is a picture of a motor nerve. I think it kind of looks like some modern art I saw the other day or a face to the side. It kind of reminds me of the ink blot pictures.
Light touch two types of mechanoreceptors. The first type consists of nerve endings that are wrapped around the base of the hair follicles. The second type is a light touch mechanoreceptor which is made up of small cup-shaped cells and naked nerve endings that come in contact with them. They are on the outside layer of the skin. Temperature is extremely important one I think because it can detect hot and cold sensation. If the temperature is too hot or too cold the receptors are activated.
-Encapsulated receptors are made up of nerve endings that are surrounded by one or more layers of cells. The largest encapsulated nerve ending is the Pacinian corpuscle. It kind of looks like an onion that has been speared by a wire. They are located in the deep tissue layers of the skin. These are stimulated by pressure like that you feel when you are sitting on the couch. Another type of sensory receptor is called the Meissner’s corpuscle. They respond to a light touch and are located in the outermost layer of the dermis. They are the most abundant in the tips of the finger and on the lips. Proprioception is a sense of position. They are located in the joints and these receptors inform us of what our limbs are doing. Golgi tendon organs are made up of connecctive tissue fibers that are surrounded by nerve endings and encased in a capsule. It is helpful in muscle contraction and knee jerk reflexes.
All these receptors are subject to change which is called adaptation. This happens whent eh receptors stop sending impulses even though the stimulus is still happening. An example of this is when you first put on a pair of earrings, or put in a pair of contacts it was bothersome at first but then you got used to it.
-Taste buds respond to different foods differently depending on the chemicals that they possess. Below is a picture of the tongue in a cartoon format. It is showing where the taste buds are that deliniate the different tastes.
Taste buds are located on the tongue. Since the taste buds respond differently to different chemicals in foods they are referred to as chemoreceptors. At the end of each taste bud it has micovilli (taste hairs). Taste buds have five flavors; sweet (stimulated by sugars and amino acids), sour stimulated by acidic substances), bitter (stimulated by alkaloids), salty (stimulated by metal ions), and umami (stimulated by meat flavors MSG too). The taste of something we eat is determined by the amounts of the stimulus it contains.
-The olfactory epithelium is a patch of receptors that detect different smells that are given off by various items. It is a chemical sense. These receptors are located in the roof of the nasal cavity. There are about 50 million olfactory receptor cells in the olfactory membrane. There are 1000 different protein receptor molecules that the olfactory hairs can bond with to create a specific odor. The receptors for smell adapt very quickly to its surrounding smells which is why a lot of times we can’t smell things that others can when they first time walk into a room. We have already adapted to the smell that is good or bad.
-Smell and taste go hand in hand. Molecules that re released by food they enter into your nasal cavity and dissolve in the watery substance in your olfactory membrane and stimulate receptor cells. It smells so good I think I could taste it is not too far off base. That is why food does not taste as good when you are sick as it does when you aren’t.
-The eye is my favorite of all the senses. Below is a picture of an eye inside and outside.
The eye is spherical shaped. The eye consists of three layers. The outer layer is made up of the sclera (eye muscles) which is the white part of the eye and the cornea which is the clear part inside the eye. The cornea allows light to come in. The middle layer consists of three parts; the choroid, ciliary body, and the iris. The choroid is the largest portion of the middle layer and it absorbs stray light and it provides that proper nutrients to the eye. The ciliary body contains smooth muscle fibers that control the shape of the lens, and permits us to be able to focus on incoming light and images. The iris is the colored potion of the eye and it also regulates the amount of light entering into the eye. The dark opening in the iris is called the pupil. The pupil allows light to come into the eye. The inner layer is called the retina. The outer layer of the retina is pigmented layer and the inner layer consists of photoreceptors and associated nerve cells. Two types of photoreceptors are in the retina called rods and cones. Rods are sensitive to light usually used for night vision and are located in the periphery of the retina. The cones are used for day vision and are in the macula and fovea. There are about 150 million rods in each EYE! And about 6 million cones. The images from our field of vision are brought into the eye and then into the retina and impulses are transmitted to the visual cortex of the brain. Some processing happens in the retina and the rest happens in the brain. When we see the image it is upside down brought onto the fovea and then the brain processes the information and gives us a right side up image. I think that is awesome! The cornea and lens focus light on the retina. The incoming light is focused on the photoreceptors of the retina by the lens.
Perfect vision is 20/20. Meaning that objects further than 6 meters away are in perfect focus by the retina. -However there are a few types of vision problems.
Nearsightedness is when the eyeball is a bit elongated. Without glasses parallel light rays arising from distant images come into focus in the front of the retina which makes the image blurry. It can also be a result of the lens being too strong or too concave. It is genetic and it generally appears around the age of 12 and gets worse as the child gets to the age of 20.
Farsightedness is the opposite of nearsightedness. It results in the eyeballs being too short or the lens is too weak (too convex). Farsightedness is generally present from birth and tends to run in the families. With this type of seeing problem people can see things far away but things up close are fuzzy.
Another type of eye problem is called astigmatism. This is an unequal curvature in the eye. It is kind of shaped like a basketball. It causes the person to see things in a fuzzy manner. It is usually something that you have when you are born and it is not something that gets worst or goes away as you mature in age.
-Presbyopia is a condition that people over the age of 40 usually develop that makes it hard for people to focus on nearby objects. It can be corrected by wearing eye glasses during such needed activities such as reading, sewing, needlepoint etc.
-Color blindness is in about 5% of the population and it is hereditary and is more common in men then women. This defect is from as simple as not being able to distinguish certain shades of color to not even being able to perceive a color. If you have red-green colorblindness then the body is missing the red or green cones in the eye. If you don’t have enough red cones then you see red as green and if you are missing the green cones then green objects appear red. The only problem I could see this with is if you did not know the position of the stoplight colors. Red at top, yellow in middle and green on bottom then you would not know whether or not to stop or go.
The ear in a human is considered to be a special sense. It has two functions the most obvious one is to hear, and maintain balance and body position.
-The ear is made up of three parts; the outer ear, the middle ear, and the inner ear. Below is a picture of the ear and its parts to make it easier to identify what is being discussed.
The outer ear is basically that… the outside of the ear. It is an irregular shaped cartilage that is covered by skin and the earlobe. It also consists of a short tube called the external auditory canal and this tube moves airborne sound waves into the middle ear. This is where you will find the nice product called earwax. Earwax is helpful in combating bacteria or anything that might be trapped in the ear. Also it contains an antibiotic substance that helps reducing ear infections.
The middle ear is contained within the skull. The eardrum, or tympanic membrane separates the middle ear cavity from the external auditory canal. Inside the middle ear there are three minuscule bones called the ossicles and they transmit sound to the cochlea in the inner ear. Going from the outside to the inside they are as follows; hammered shaped malleus, incus, and the stirrup shaped bone stapes. When the membrane is struck by the sound waves it then vibrates and causes the malleus moves back and forth. Then the incus vibrates which causes the stapes to move in and out against the oval window. It kind of looks like the head of a drum.
The eustachian tube helps to equalize pressure in the middle ear. It helps to balance out the pressure internally and externally. When there is a change in elevation and the feeling of the ears popping this is the eustachian tube equaling out the pressure.
The inner ear occupies the large cavity in the temporal bone of the skull and contains two sensory organs, the cochlea (snail shaped) and the vestibular apparatus which is made up of two parts; the semicircular canals and the vestibule. The semicircular canals are three ringlike structures filled with fluid set at right angles to one another. They house the receptors that tell the body the position and movement. The receptors for head movement are located in there. There are two membranous sacs in the vestibule, the utricle and the saccule, contain receptors that respond to linear acceleration and tilting of the head.
The musculoskeletal system is made up of bones, joints, and muscles. In adults muscles make up about 50% to 60% of the body weight.
Bones have many functions for the body. They give internal support, create movement, and protect the internal organs. In addition to all those important functions they also produce blood cells and platelets, store fat, and help to regulate the blood calcium levels in the body.
-The skeleton consists of two parts. The axial skeleton consists of the skull, spine, and the rib cage. The second part is called the appendicular skeleton and this consists of the arms, shoulders, legs, and pelvis.
-Bones are made up of a dense outer layer and a less compact central region or spongy bone.
The outer layer of the compact bone is a layer of connective tissue. This tissue is called periostemon and it serves as a site of attachment for skeletal muscles by tendons and is filled with nerve fibers. Inside the bone is a large cavity called the marrow cavity. There is red marrow which is found in a fetus or in a newborn. As people age everyone’s marrow turns to yellow. Yellow marrow can be reactivated to produce blood cells under certain circumstances when an injury occurs. Bones are remodeled for strength when exposed to new stresses. Multinucleated cells that are present on the spongy bones are called osteoclasts. Osteoclasts are very large cells that digest bone with enzymes. Osteoclasts tear down some of the spongy bone whereas osteoblasts rebuild new compact bone, causing it to thicken to meet new stresses. Osteoporosis is a disease of the bone that is caused by a progressive loss of calcium in the bones. It makes the bones become brittle and weak which in turn can make for an easy break. It is most common among women that are going through menopause and are losing the estrogen hormone and it can also occur in people that are immobile for long periods of time. It can be reversed through calcium supplements, calcium rich foods, estrogen therapy and exercise.
-Joints permit varying degrees of mobility. Mobility occurs when bone and muscles work together. Joints are the structures that connect the bones of the skeleton. Some joints only allow little mobility and they are called slightly moveable (the vertebrae) and other joints that permit no mobility are called immovable joints (skull bones connecting together to form the skull) and the last bit of joints that allow free movement or synovial joints are called movable joints (arms). Joints have cartilage that are located on the surface of the bone and connective tissue that that form ligaments that join bone to bone together. Ligaments are not very flexible. Synovial fluid provides nutrients to the cartilage and it is like a lubricant. Tendons and muscles provide additional support in the joints. Two of the most common synovial joints are the hinge joints (knees and fingers) that have limited mobility and the ball-in-socket (hips and shoulders) that have a wider range of mobility. Below is a picture of a synovial joint along with all the parts that are of importance when thinking about it.
-Joints can be injured in one of three common ways. Dislocation which is caused by a fall or some other body movement that does not agree with the joint. It is when the joint “pops” out so to speak and is moved from its correct position. It is sometimes accompanied by a sprain, inflammation, and immobility. This often times happens with shoulders, fingers, or knees and it is necessary for it to be put back into place in order for the joint to function properly. A sprain is another common injury when we are talking about joints. It is usually a partially or completely torn ligament and it heals slowly. It has to be repaired a lot of times with surgery when the ligament is completely torn. Cartilage tears are another common joint injury. It can happen if the joints are twisted or when pressure is applied to them. Cartilage tears are usually done by surgically removing it and it sometimes makes the joints less stable and this usually occurs in the knee joints. Osteoarthritis is caused by wear and tear on the cartilage. One of the most common problems is called degenerative joint disease or osteoarthritis. Excessive wear and tear on the joints causes cartilage to crack and flake. It most of the time it occurs on weight bearing joints. There is also rheumatoid arthritis is another common disorder it is an autoimmune disease and it is the most crippling and painful form of arthritis. It occurs in people between the ages of 20 and 40. It is a permanent condition that can be with physical therapy, painkillers, anti-inflammatory drugs, and surgery. Below is a picture of a bone iwht muscle fibers and it also shows the marrow. Everything is labeled for easy understanding.
The skeletal muscles allow a wide range of movement. Skeletal muscles are controlled by the nervous system. Most skeletal muscles are stretched over one or more joints and so when they contract it then causes movement. Muscles often times work in groups to produce movement or different activities. Skeletal muscles are both excitable and contractile and they consist of long unbranched muscle fibers. They appear striped or striated if looked at under a microscope. These fibers are very elastic and are capable of returning to there regular position and look after they are flexed or released. Inside the muscle fibers can be found numerous myofibrils, bundles of contractile filaments like the proteins actin and myosin which are stimulated by nerve impulses. During muscle contraction or shortening the actin filaments are pulled by the myosin molecules that cause them to slide inward. The attachment of the myosin and actin molecules are stimulated by the release of calcium inside the muscle cells. ATP in the muscle provides the energy necessary to pull the actin filaments inward. ATP is used regularly when you are talking about muscle cells.
A single contraction followed by relaxing is called a switch. The engagement of additional muscle fibers during contraction is called recruitment. The motor neuron and the muscle fibers it supplies constitute a motor unit. Motor units account for the degree of control that various muscles put forth. In order for the force of the contraction to be stronger more motor neurons are stimulated. The strength of a muscle contraction can also be increased by a process called wave stimulation. The firmness that your muscle has is called muscle tone. It is essential for maintaining posture. It also generates heat in any warm blooded animals. Muscle tone results from the contraction of the muscle fibers during periods where you are not as active. The skeletal muscles have two types of muscle fibers called slow an dfast twitches. Slow twitch fibers contract relatively slow but have a lot of endurance. Fast-twitch muscle fibers contract swiftly. The muscles of sprinters and other athletes whose performance depends on quick bursts of activity contain a high proportion of fast-twitch fibers. Skeletal muscles have a pretty good ocmbination of slow and fast-twitch fibers giving the muscles overall a very good performance. Increasing muscle mass and endurance go hand and hand. Muscle protein is quickly made and destroyed. Half of the muscles you gain in lifting weights is lost within 2 weeks after stopping the exercise. High intensity exercise like weightlifting builds muscles relatively easy and takes very little of it to see a change. Whereas low intensity exercise such as aerobics and swimming don’t build bulk muscle but it does increase in our endurance. Increased endurance also is a result of improving the function of the respiratory system and blood flow.
The skeleton and the muscles that connect it are important in mobility and overall health. Any malfunction in one area or another may result in painful consequences. Just like with all systems in the body it is a complex network all working together to improve our overall performance.
The first one is called the naked nerve ending receptors.
These nerve endings can detect pain, temperature, and light touching. There are two types of pain and they are called somatic and visceral.
Somatic pain is a result of injuries in the skin, joints, muscles and tendons. The response can be a result of many types of injuries that may occur such as pinching, cutting, breaking, crushing, or even hot and cold temperatures.
Visceral pain is a result from the stimulation of naked nerve endings in the body organs (viscera). Pain receptors are often stimulated by expansion. For example, pain in the intestinal track might be caused by gas stretching the naked nerve fibers in the walls of the intestines. In other body organs the pain receptors could be caused by a lack of oxygen. Somatic pain is easily identified (pinching) whereas visceral pain is often vague and hard to localize (chest pain is it the lungs, heart?) Visceral pain that appears on the body surface but away from the actual location of the pain is called referred pain. Below is a picture of a motor nerve. I think it kind of looks like some modern art I saw the other day or a face to the side. It kind of reminds me of the ink blot pictures.
Light touch two types of mechanoreceptors. The first type consists of nerve endings that are wrapped around the base of the hair follicles. The second type is a light touch mechanoreceptor which is made up of small cup-shaped cells and naked nerve endings that come in contact with them. They are on the outside layer of the skin. Temperature is extremely important one I think because it can detect hot and cold sensation. If the temperature is too hot or too cold the receptors are activated.
-Encapsulated receptors are made up of nerve endings that are surrounded by one or more layers of cells. The largest encapsulated nerve ending is the Pacinian corpuscle. It kind of looks like an onion that has been speared by a wire. They are located in the deep tissue layers of the skin. These are stimulated by pressure like that you feel when you are sitting on the couch. Another type of sensory receptor is called the Meissner’s corpuscle. They respond to a light touch and are located in the outermost layer of the dermis. They are the most abundant in the tips of the finger and on the lips. Proprioception is a sense of position. They are located in the joints and these receptors inform us of what our limbs are doing. Golgi tendon organs are made up of connecctive tissue fibers that are surrounded by nerve endings and encased in a capsule. It is helpful in muscle contraction and knee jerk reflexes.
All these receptors are subject to change which is called adaptation. This happens whent eh receptors stop sending impulses even though the stimulus is still happening. An example of this is when you first put on a pair of earrings, or put in a pair of contacts it was bothersome at first but then you got used to it.
-Taste buds respond to different foods differently depending on the chemicals that they possess. Below is a picture of the tongue in a cartoon format. It is showing where the taste buds are that deliniate the different tastes.
Taste buds are located on the tongue. Since the taste buds respond differently to different chemicals in foods they are referred to as chemoreceptors. At the end of each taste bud it has micovilli (taste hairs). Taste buds have five flavors; sweet (stimulated by sugars and amino acids), sour stimulated by acidic substances), bitter (stimulated by alkaloids), salty (stimulated by metal ions), and umami (stimulated by meat flavors MSG too). The taste of something we eat is determined by the amounts of the stimulus it contains.-The olfactory epithelium is a patch of receptors that detect different smells that are given off by various items. It is a chemical sense. These receptors are located in the roof of the nasal cavity. There are about 50 million olfactory receptor cells in the olfactory membrane. There are 1000 different protein receptor molecules that the olfactory hairs can bond with to create a specific odor. The receptors for smell adapt very quickly to its surrounding smells which is why a lot of times we can’t smell things that others can when they first time walk into a room. We have already adapted to the smell that is good or bad.
-Smell and taste go hand in hand. Molecules that re released by food they enter into your nasal cavity and dissolve in the watery substance in your olfactory membrane and stimulate receptor cells. It smells so good I think I could taste it is not too far off base. That is why food does not taste as good when you are sick as it does when you aren’t.
-The eye is my favorite of all the senses. Below is a picture of an eye inside and outside.
The eye is spherical shaped. The eye consists of three layers. The outer layer is made up of the sclera (eye muscles) which is the white part of the eye and the cornea which is the clear part inside the eye. The cornea allows light to come in. The middle layer consists of three parts; the choroid, ciliary body, and the iris. The choroid is the largest portion of the middle layer and it absorbs stray light and it provides that proper nutrients to the eye. The ciliary body contains smooth muscle fibers that control the shape of the lens, and permits us to be able to focus on incoming light and images. The iris is the colored potion of the eye and it also regulates the amount of light entering into the eye. The dark opening in the iris is called the pupil. The pupil allows light to come into the eye. The inner layer is called the retina. The outer layer of the retina is pigmented layer and the inner layer consists of photoreceptors and associated nerve cells. Two types of photoreceptors are in the retina called rods and cones. Rods are sensitive to light usually used for night vision and are located in the periphery of the retina. The cones are used for day vision and are in the macula and fovea. There are about 150 million rods in each EYE! And about 6 million cones. The images from our field of vision are brought into the eye and then into the retina and impulses are transmitted to the visual cortex of the brain. Some processing happens in the retina and the rest happens in the brain. When we see the image it is upside down brought onto the fovea and then the brain processes the information and gives us a right side up image. I think that is awesome! The cornea and lens focus light on the retina. The incoming light is focused on the photoreceptors of the retina by the lens.Perfect vision is 20/20. Meaning that objects further than 6 meters away are in perfect focus by the retina. -However there are a few types of vision problems.
Nearsightedness is when the eyeball is a bit elongated. Without glasses parallel light rays arising from distant images come into focus in the front of the retina which makes the image blurry. It can also be a result of the lens being too strong or too concave. It is genetic and it generally appears around the age of 12 and gets worse as the child gets to the age of 20.
Farsightedness is the opposite of nearsightedness. It results in the eyeballs being too short or the lens is too weak (too convex). Farsightedness is generally present from birth and tends to run in the families. With this type of seeing problem people can see things far away but things up close are fuzzy.
Another type of eye problem is called astigmatism. This is an unequal curvature in the eye. It is kind of shaped like a basketball. It causes the person to see things in a fuzzy manner. It is usually something that you have when you are born and it is not something that gets worst or goes away as you mature in age.
-Presbyopia is a condition that people over the age of 40 usually develop that makes it hard for people to focus on nearby objects. It can be corrected by wearing eye glasses during such needed activities such as reading, sewing, needlepoint etc.
-Color blindness is in about 5% of the population and it is hereditary and is more common in men then women. This defect is from as simple as not being able to distinguish certain shades of color to not even being able to perceive a color. If you have red-green colorblindness then the body is missing the red or green cones in the eye. If you don’t have enough red cones then you see red as green and if you are missing the green cones then green objects appear red. The only problem I could see this with is if you did not know the position of the stoplight colors. Red at top, yellow in middle and green on bottom then you would not know whether or not to stop or go.
The ear in a human is considered to be a special sense. It has two functions the most obvious one is to hear, and maintain balance and body position.
-The ear is made up of three parts; the outer ear, the middle ear, and the inner ear. Below is a picture of the ear and its parts to make it easier to identify what is being discussed.
The outer ear is basically that… the outside of the ear. It is an irregular shaped cartilage that is covered by skin and the earlobe. It also consists of a short tube called the external auditory canal and this tube moves airborne sound waves into the middle ear. This is where you will find the nice product called earwax. Earwax is helpful in combating bacteria or anything that might be trapped in the ear. Also it contains an antibiotic substance that helps reducing ear infections.
The middle ear is contained within the skull. The eardrum, or tympanic membrane separates the middle ear cavity from the external auditory canal. Inside the middle ear there are three minuscule bones called the ossicles and they transmit sound to the cochlea in the inner ear. Going from the outside to the inside they are as follows; hammered shaped malleus, incus, and the stirrup shaped bone stapes. When the membrane is struck by the sound waves it then vibrates and causes the malleus moves back and forth. Then the incus vibrates which causes the stapes to move in and out against the oval window. It kind of looks like the head of a drum.
The eustachian tube helps to equalize pressure in the middle ear. It helps to balance out the pressure internally and externally. When there is a change in elevation and the feeling of the ears popping this is the eustachian tube equaling out the pressure.
The inner ear occupies the large cavity in the temporal bone of the skull and contains two sensory organs, the cochlea (snail shaped) and the vestibular apparatus which is made up of two parts; the semicircular canals and the vestibule. The semicircular canals are three ringlike structures filled with fluid set at right angles to one another. They house the receptors that tell the body the position and movement. The receptors for head movement are located in there. There are two membranous sacs in the vestibule, the utricle and the saccule, contain receptors that respond to linear acceleration and tilting of the head.
The musculoskeletal system is made up of bones, joints, and muscles. In adults muscles make up about 50% to 60% of the body weight.
Bones have many functions for the body. They give internal support, create movement, and protect the internal organs. In addition to all those important functions they also produce blood cells and platelets, store fat, and help to regulate the blood calcium levels in the body.
-The skeleton consists of two parts. The axial skeleton consists of the skull, spine, and the rib cage. The second part is called the appendicular skeleton and this consists of the arms, shoulders, legs, and pelvis.
-Bones are made up of a dense outer layer and a less compact central region or spongy bone.
The outer layer of the compact bone is a layer of connective tissue. This tissue is called periostemon and it serves as a site of attachment for skeletal muscles by tendons and is filled with nerve fibers. Inside the bone is a large cavity called the marrow cavity. There is red marrow which is found in a fetus or in a newborn. As people age everyone’s marrow turns to yellow. Yellow marrow can be reactivated to produce blood cells under certain circumstances when an injury occurs. Bones are remodeled for strength when exposed to new stresses. Multinucleated cells that are present on the spongy bones are called osteoclasts. Osteoclasts are very large cells that digest bone with enzymes. Osteoclasts tear down some of the spongy bone whereas osteoblasts rebuild new compact bone, causing it to thicken to meet new stresses. Osteoporosis is a disease of the bone that is caused by a progressive loss of calcium in the bones. It makes the bones become brittle and weak which in turn can make for an easy break. It is most common among women that are going through menopause and are losing the estrogen hormone and it can also occur in people that are immobile for long periods of time. It can be reversed through calcium supplements, calcium rich foods, estrogen therapy and exercise.
-Joints permit varying degrees of mobility. Mobility occurs when bone and muscles work together. Joints are the structures that connect the bones of the skeleton. Some joints only allow little mobility and they are called slightly moveable (the vertebrae) and other joints that permit no mobility are called immovable joints (skull bones connecting together to form the skull) and the last bit of joints that allow free movement or synovial joints are called movable joints (arms). Joints have cartilage that are located on the surface of the bone and connective tissue that that form ligaments that join bone to bone together. Ligaments are not very flexible. Synovial fluid provides nutrients to the cartilage and it is like a lubricant. Tendons and muscles provide additional support in the joints. Two of the most common synovial joints are the hinge joints (knees and fingers) that have limited mobility and the ball-in-socket (hips and shoulders) that have a wider range of mobility. Below is a picture of a synovial joint along with all the parts that are of importance when thinking about it.
-Joints can be injured in one of three common ways. Dislocation which is caused by a fall or some other body movement that does not agree with the joint. It is when the joint “pops” out so to speak and is moved from its correct position. It is sometimes accompanied by a sprain, inflammation, and immobility. This often times happens with shoulders, fingers, or knees and it is necessary for it to be put back into place in order for the joint to function properly. A sprain is another common injury when we are talking about joints. It is usually a partially or completely torn ligament and it heals slowly. It has to be repaired a lot of times with surgery when the ligament is completely torn. Cartilage tears are another common joint injury. It can happen if the joints are twisted or when pressure is applied to them. Cartilage tears are usually done by surgically removing it and it sometimes makes the joints less stable and this usually occurs in the knee joints. Osteoarthritis is caused by wear and tear on the cartilage. One of the most common problems is called degenerative joint disease or osteoarthritis. Excessive wear and tear on the joints causes cartilage to crack and flake. It most of the time it occurs on weight bearing joints. There is also rheumatoid arthritis is another common disorder it is an autoimmune disease and it is the most crippling and painful form of arthritis. It occurs in people between the ages of 20 and 40. It is a permanent condition that can be with physical therapy, painkillers, anti-inflammatory drugs, and surgery. Below is a picture of a bone iwht muscle fibers and it also shows the marrow. Everything is labeled for easy understanding.
The skeletal muscles allow a wide range of movement. Skeletal muscles are controlled by the nervous system. Most skeletal muscles are stretched over one or more joints and so when they contract it then causes movement. Muscles often times work in groups to produce movement or different activities. Skeletal muscles are both excitable and contractile and they consist of long unbranched muscle fibers. They appear striped or striated if looked at under a microscope. These fibers are very elastic and are capable of returning to there regular position and look after they are flexed or released. Inside the muscle fibers can be found numerous myofibrils, bundles of contractile filaments like the proteins actin and myosin which are stimulated by nerve impulses. During muscle contraction or shortening the actin filaments are pulled by the myosin molecules that cause them to slide inward. The attachment of the myosin and actin molecules are stimulated by the release of calcium inside the muscle cells. ATP in the muscle provides the energy necessary to pull the actin filaments inward. ATP is used regularly when you are talking about muscle cells.
A single contraction followed by relaxing is called a switch. The engagement of additional muscle fibers during contraction is called recruitment. The motor neuron and the muscle fibers it supplies constitute a motor unit. Motor units account for the degree of control that various muscles put forth. In order for the force of the contraction to be stronger more motor neurons are stimulated. The strength of a muscle contraction can also be increased by a process called wave stimulation. The firmness that your muscle has is called muscle tone. It is essential for maintaining posture. It also generates heat in any warm blooded animals. Muscle tone results from the contraction of the muscle fibers during periods where you are not as active. The skeletal muscles have two types of muscle fibers called slow an dfast twitches. Slow twitch fibers contract relatively slow but have a lot of endurance. Fast-twitch muscle fibers contract swiftly. The muscles of sprinters and other athletes whose performance depends on quick bursts of activity contain a high proportion of fast-twitch fibers. Skeletal muscles have a pretty good ocmbination of slow and fast-twitch fibers giving the muscles overall a very good performance. Increasing muscle mass and endurance go hand and hand. Muscle protein is quickly made and destroyed. Half of the muscles you gain in lifting weights is lost within 2 weeks after stopping the exercise. High intensity exercise like weightlifting builds muscles relatively easy and takes very little of it to see a change. Whereas low intensity exercise such as aerobics and swimming don’t build bulk muscle but it does increase in our endurance. Increased endurance also is a result of improving the function of the respiratory system and blood flow.
The skeleton and the muscles that connect it are important in mobility and overall health. Any malfunction in one area or another may result in painful consequences. Just like with all systems in the body it is a complex network all working together to improve our overall performance.
Subscribe to:
Posts (Atom)