ComPenDiuM ReviEW for NuTriTion & DiGesTioN

Internal Body Maintenance

Table Of Contents For
Nutrition & Digestion

I. Nutrition (5)

A. Macronutrients
1. Water
3. Carbohydrates
4. Lipids
5. Amino Acids & Protein

B. Micronutrients
1. Vitamins & Minerals
2. Food Functions

II. The Digestive System

A. Passage of Food
1. Mouth, Tongue & Teeth
2. Epiglottis, Esophagus, & Stomach
3. Chyme, Small Intestines, Pancreas, Liver
4. Intestinal Epithelium & Large Intestines

III. Respiratory System

A. Passageway of air
1. Parts and functions

B. Gas exchange
1. Oxygen & Carbon Dioxide

C. Breathing & Control of Respiration
1. Inspiration & Expiration

D. Diseases of Respiratory System
1. Viral & bacterial Infections
2. Asthma & Emphysema

IV. Glucose & Diffusion

A. Kreb’s Cycle
B. Diabetes Type I & II & Gestational

*Nutrition*
When I think of nutrition one cartoon from childhood pops into mind and that is the one from, “Schoolhouse Rock” with that song, “You are what you eat.” It is hard to believe but what is consumed now with effect our bodies in the future. It is important to eat a balanced diet with a fair dispersement of the proper nutrients, vitamins and minerals to function accordingly. The US Department of Agriculture designed a food pyramid to help people eat healthier. In this food pyramid there are six main food groups with the amounts that people should consume have the proper nutrition. The nutrients that are necessary to survive and maintain healthiness can be split up into two categories; macronutrients and micronutrients.
*Macronutrients*
-Macronutrients consist of five basic things; water, amino acids and proteins, lipids, and carbohydrates. These can be found in various foods and drinks, milk and milk products, meats, nuts, oils, seeds, breads pastas, cereals, and sweets. Macronutrients are needed in large quantities and water is the most important. ---Without water the average person would not be able to survive for more then 3 days. The body has to maintain sufficient water intake because it is involved in many chemical reactions in the body. Water helps to maintain proper body temperature too.
-Carbohydrates are a major source of energy for the body. They primarily consist of carbon, hydrogen, and oxygen. There are three types of groups that carbohydrates fall into; monosaccharides, dissacharides, and polysaccharides. Monosaccharides are usually categorized as simple sugars like glucose. Disaccharides are two monosaccharides stuck together such as glucose and fructose. Glucose molecules are stored in the liver and muscle as glycogen. Starches fall into this category as well. Starches are found in plants usually in leaves and roots. An example of a starch is a potato. The body breaks down starches into sugars and then the body uses it for energy. Another important carbohydrate that can’t be digested is cellulose. Cellulose is aids in the passage of fecal matter through the intestinal tract and reduces the incidence of colon cancer.
-Lipids are a great source of energy and are also known for supplying the body with a layers of heat-conserving insulation. They are insoluble in water and are usually greasy, waxy, or oily. There are two important lipids that should come to mind. Triglycerides are known as fats and oils. These are found in animal fats. One of the best known steroids is cholesterol. It comes for the liver and lesser amounts come from diets.
-Proteins in food are broken down to amino acids in the small intestines, which are then used to make enzymes and hormones in the cells of the body and are absorbed in the bloodstream. In order to supply the body with all the amino acids people should consume complete proteins that can be found in milk or eggs.
*Micronutrients*
-Micronutrients consist of two basic things; vitamins and minerals. These two things can be found in veggies, fruits, meats, nuts, and seeds.
-Vitamins are only required in small quantities for normal metabolism. An overabundance and insufficiency of vitamins or minerals can have serious effects on the human health. When talking about vitamins they can be broken down into two categories; water-soluble and fat-insoluble. The water soluble ones are vitamin C and B complex. The fat-soluble vitamins are A, D, E, and K.
-Minerals can be broken down into two categories; trace minerals (these are minerals that are needed in small amounts) and major minerals (these are minerals that are needed in large amounts).
-There are many foods that are consumed by people that are considered to be unhealthy but there are a few foods that are considered to be beneficial and they are called functional foods. These foods have been used to reduce cholesterol and prevent some diseases. Some substances that are filled with benefits to the body are antioxidants. Eating foods rich in antioxidants have been known to reduce heart and artery disease. One example of an antioxidant is chocolate. My favorite! Yum! Another example of a food that is rich in antioxidants are fruits and vegetables. Antioxidants have also been used to help in cancer.
*Digestive System*
The digestive system is where food is broken down, filtered through, and dispersed throughout the body for nutrients and energy.
-Digestion begins when food is placed in the mouth. Salivary glands produce saliva which is used to help liquefy it. -Salation is stimulated by smells, tasting, smell, and sometimes even by thoughts of the favorites foods. This is an example of a nervous reflex in the body. Along with the chopping of the teeth food is pulverized and then swallowed. The tongue plays a major role in making this happen. Then the tongue pushes food to the back of the oral cavity into the pharynx.
-Food is then thrust into the esophagus (the food tube to the stomach) and the trachea or windpipe is right in front of it. So to prevent the food from heading down the wrong pipe the epiglottis is like the trapdoor closing the opening to the trachea. Swallowing is an involuntary act and then from there food moving through the body is automatic. Involuntary muscle contractions (called peristalsis) in the esophagus moves food through. The stomach produces pepsin which breaks proteins into peptides and hydrochloric acid which denatures protein allowing it to be acted on by enzymes. The stomach is regulated by neutral and hormonal mechanisms. The food is stored in the stomach and the opening to the stomach is covered by the sphincter. Gastric juices are produced in the stomach which helps to churn the food and turn it into a watery paste called chyme.
-Chyme leaves the stomach and then enters into the small intestines by peristaltic muscle contractions. The small intestines serves as a site to food digestion and absorption. The small intestines coil in the abdominal region that is about 6 meters long in adults. When thinking about the small intestines remember that the intestines are broken into three parts; the duodenum, jejunum, and the ileum. Enzymes are used to help break down large molecules into smaller molecules. In the walls of the small intestines are lacteals and they are used to absorb and move fats through the body. The pancreas is located beneath the stomach and is nestled in a loop formed by the first portion of the small intestines. This organ is has endocrine and exocrine functions. When functioning as an endocrine gland it produces enzymes and sodium bicarbonate that is used in digestion. Endocrine functioning takes place by producing hormones like insulin and glucagon that help keep homeostasis regulated. The pancreas produces juices and releases about 1 to 1.5 quarts into the small intestines EACH day! These secretions are often stimulated by hormones that are released in the small intestines. The liver carries out many functions in digestion. It is one of the largest and most versatile organ in the body. It has about 500 different jobs. It is protected by the rib cage and is located in the right side of your body just above the stomach. The liver helps to synthesize blood proteins that are used in blood clotting. It also filters out the foreign chemicals introduced into the body such as alcohol and nicotine. As well as producing an important substance called bile that is a fluid that is used in breaking down fats in the body. The gallbladder and the liver work hand in hand. After bile is produced in the liver it is then moved into the gallbladder where it is stored until it is needed in the small intestines.
-Intestinal Epithelium is what the lining of the intestines is called and it is what is needed to help the body absorb the necessary ingredients for the body to function properly. When talking about absorption and digestion there are three common mechanisms; diffusion, osmosis, and active transport.
-The large intestines are primarily used for the transport of wastes (feces, the leftovers, the unabsorbed, unused, ingredients that the body doesn’t need) and the reabsorption of water. The large intestines are broken up into three main components; the cecum (the connector between the small and large intestines), appendix (wormlike structure that attaches to the cecum) , and colon (mainly what the large intestine is made up of). The colon then empties into the rectum.
*Respiratory System*
The main function of the respiratory system is to supply oxygen to the body and get rid of carbon dioxide. In order for successful breathing and repiration to take place there are a few key components in order to make this possible. It is not as simple as breathe in through the nose and blow out through the mouth. It is split into two primary activities that are happening which are; air conducting (transportation of air to the lungs) and gas-exchange (oxygen absorption and carbon dioxide release).
*Passageway of air*
-Mouth or nose>>pharynx>>larynx>>trachea>>bronchi>>lungs>>
-The first point of entry would either be through the nasal cavity or the oral cavity. The nasal and oral cavities take in air, then filters it, warms it, and moves it through to the pharynx. The oral cavity also helps to produce noise.
-Then off to the pharynx this is the funnel shaped structure that opens to the nose and mouth and opens below the larynx.
-The larynx is the voice box that holds the vocal cords, it also transports air to the trachea and it warms and fliters the air a little bit more.
-The epiglottis is vital here because as we are breathing this flap opens to allow air to pass through or when we are swallowing it covers the trachea so food does not get lodged. It is doorman of the body for food or oxygen.
-The larynx opens to the trachea or otherwise known as the windpipe.
-The trachea then divides into two large branches that are called the bronchi that go to the lungs. Air is continuing to be warmed throughout the whole process.
-The bronchioles control the air flow in the lungs and transport air to alveoli.
-The alveoli are small air sacs in the lungs. This is where oxygen exchange takes place in the blood stream. This gas exchange is aided by an important cell called the alveolar macrophage otherwise known as the dust cell. It is the clean up crew of the gas exchange process.
*Gas Exchange*
The respiratory system is a complex system of gas exchange. Air is brought into the body through the mouth. Oxygen and carbon dioxide are diffused across the alveolar walls and into the bloodstream.
-Oxygen diffuses into the blood plasma, and then into the red blood cells, where it binds to hemoglobin.
-Carbon dioxide is a leftover product of the gas exchange. Most of this gas gets wrapped up with the red blood cells and is then changed into carbonic acid. The carbonic acid then goes into the blood plasma.
*Breathing & the Control of Respiration*
Breathing is an involuntary action meaning we do not have to tell ourselves to breath in order to keep breathing and that is all controlled by the brain stem. That might be a problem during sleep.
-Nerve cells send impulses to the diaphragm and it contracts. This action causes the thoracic area to expand and draw in air through the mouth or nose. This action is called inhalation or inspiration.
-When the lungs fill completely then the muscles relaxed causing the air to be expelled, or otherwise known as expiration. Supplemental help can come fromt eh abdominal and chest muscles in order to completely exhale the air.
*Diseases of the Respiratory System*
Diseases of the respiratory system are common. Here are some examples of some diseases that occur in the respiratory system.
-Bacteria and viruses can infect many parts of the respiratory system. One that is common is bronchitis. This is an infection in the bronchi. Another is sinusitis which is an infection in the sinuses. When people lose there voice it is called laryngitis. This is caused by the inflammation of the lining of the larynx and vocal cords.
-Asthma it is an allergic response that inhibits the ability of breathing efficiently. Often times asthma is common among school aged children but as they grow into adulthood it often times disappears or the effects lessen. One of the most common treatments for asthma is an inhaler.
-Emphysema is another respiratory disease and it is caused by the breakdown of the alveoli which is caused by chemical irritants such as smoking and air pollution. There is no known cure for this disease.
-Lung cancer is another horrible disease in the respiratory system which is caused by smoking.
*Glucose Diffusion*
Glucose is the main ingredient that gets combined with oxygen in cellular respiration.
The first phase in cellular respiration in cells is called glycolysis.
-The main way that cells get ATP is through the Krebb’s cycle.
-Glucose diffuses through a protein pore in the cell membrane.
-Insulin is secreted into the blood by the pancreas and this usually happens after ingesting food. When the insulin is released this in turn causes the cells take in glucose and store it or use it in cellular metabolism. Glucose can be stored in the liver or muscles in the body and it is called glycogen.
When talking about abnormal functioning of either of these two processes occurs then that is when a person develops diabetes. There are two types of diabetes that are common among people.
-Diabetes type I is when a person’s pancreas is not producing insulin. This accounts for 5% to 10% of cases concerning diabetes.
-Diabetes type II is usually common among people who are overweight. This is when the cells don’t use insulin and in turn can’t use glucose. This accounts for 90% to 95% of cases of diabetes. -Gestational Diabetes is only a type of diabetes that pregnant women can get. This can develop in 2% to 5% of women who become pregnant.