Compendium Review Ch. 5,6,&7

Chapter 5 Nutrition & Digestion

Food Pyramid- A table that provides the 6 major food groups for proper nutrition

web.mit.edu/.../sportsmedicine/wcrfoodpyr.html

These six groups starting at the top begin with:

• Fats, oils and sweets
  
• Milk, yogurt and cheese
  
• Meat, poultry, fish, dry beans,eggs and nuts
  
• Vegtables
  
• Fruit
  
• Bread, cereal, rice and pasta
  

Classified in this area is two nutrients that are vital to keep proper balance. Macronutrients and micronutrients.

Marconutrients include water, amino acids and protiens, lipids, and carbohydrates.

The main macronutrient is water. This is the most inportant and it is supplied in many things that we eat and drink. It is needed for chemical reactions in the body and aids in the breakdown of many substances. This process is called hydrolysis. This is when water is added to a covelant bond causing it to split.

student.biology.arizona.edu/honors2003/group1...

Micronutrients include vitamins and minerals in minute amounts. Vitamins play a key role in chemical reactions in the body. They are an organic compound that maintains proper balance. There are 2 kinds of vitamins, water soluble and fat soluble. Water soluble vitamins are carried in the blood plasma and they are eliminated in the kidneys so they are not stored in the body. The fat soluble vitamins are stored in the body.

An excess of certain vitamins can cause major problems.

Minerals are derived from foods. 3/4 of all minerals that are out there are in humans.

Functional foods provide you with more than just the basic nutrients

Carbohydrates are an organic compound. There are three groups of carbohydrates and they are monosaccharides, disaccharides and polysaccharides. Monosaccharides are the smallest of the carbs. It is the most common and the most important glucose which is what provides energy. This is needed for metabolism, food digestion, absorption, and as well as talking walking and body movement. Disaccharides are a combination of 2 monosaccharides. There is a large partical called a polymer that is made up of many smaller particals. Polysaccharides are carbohydrate polymers. The most common building block is glucose. Plants synthesis two polysaccharides which are starch and cellulose. Animals synthesis and polysaccharide called glycogen. Stach in produced in plants in the leaves and is stored in the roots. when this is ate it breaks down into glucose molecules and provides energy. Cellulose is found only in plants and it cannot be digested by humans. We lack the enzymes to break it down. And although it cannot be digested by humans it is needed in the principle form of dietary fiber. Dietary fiber is found in fruits, vegtables and grains. There are two types of dietary fibers water soluble fiber and water insoluble fiber. Water soluble fiber is a gummy polysaccharide that works to lower cholesterol by acting like a sponge and absorbing it in the digestive tract. Water insoluble fibers are rigid cellulose molecules that increase the water content in feces and help transport it through the large intestine.

Glycogen is what is called the "animal starch." This ensures proper blood sugar levels. The livers stores this glycogen and releases it in times of low blood sugar to help maintain the body.

Lipids are a greasy, waxy, oily compound that stores energy and is structurly diverse. One type of lipid is tiyglycerides. These are fats that contain 4 units that consist of 1 glycerol and 3 fatty acids. Triglycerides are stored in cells beneath the skin and they are used to protect organs from impact.

cellbio.utmb.edu/cellbio/membrane_intro.htm

Saturated Fats are filled with hydrogen. Unsaturated fats are fatty acids that contain a number of covelant bonds. There is also polyunsaturated fats. These reduce the risk of atherosclerosis. This is a buildup of cholesterol deposits or plaque in an artery wall that restricts blood flow to the heart and brain causing heart attacks and strokes.

Trans fatty acid- increases blood cholesterol

Steroids consist of 3 six carbon rings and 1 five carbon ring and they are joined in a large structure.

Protiens are broken down to make amino acids and in turn amino acids are broke down to make enzymes and hormones in cells.

Overnutrition

• obesity
  
• overweight
  
• too much protien
  
• causes diabetes and osteoarthritis
  
• causes heart attacks and strokes
  
  

www.truehealth.org/obesity.html

Undernutrition

• lack of protien
  
• skinny
  
• emaciated
  
• muscle breaks down to provide energy
  
  

www.bio.davidson.edu/.../2002/tech/ecopoly.html

Digestive System

www.ngfl-cymru.org.uk/.../107/LP-humans.html

This is the system in which food enters the body and eventually leaves the body.

The process starts at the mouth where the food enters. The mouth breaks down the food mechanically by liquifying with saliva. Your salive kills some bacteria and cleanses your teeth. Without proper care of the teeth you can develope plaque whick traps bacteria on the teeth and rots the enamel. Enamel is needed on your teeth because it is the natural barrier that protects them. You must also keep you gums clean so you do not develope gingivits. Gingivits is a bacteria that gets trapped at the base of the gums and rots away the bone structure that the teeth are attached to in turn allowing your teeth to fall out. Another part of the mouth that plays a key roll is the tounge. Your tounge has the taste buds. It pushes the food to the pharynx which is funnel shaped and connects to the esophagus. The involuntary muscle action that helps propel your food towards the stomach is called peristalsis. Inside the esophagus is the eppiglottis. This prevents food from going down the trachea.

As food enters the lower esophagus a sphincter opens that allows the food to enter the stomach.The next place that the food goes is the stomach. This is where food is stored and eventually released in small amounts into the small intestine. Your stomach lies on the left side of your body and is protected by the rib cage. Once in the stomach your gastric glands release acidic secrections which aid in the breakdown of the food. With the use of the stomach muscle, saliva and acid, your stomach now produces a watery paste which was your food. This watery paste is known as chyme and your stomach can hold 2-4 liters of chyme. There are only a few substance such as alcohol that can pierce the lining of the stomach and enter the blood stream. Your stomach lining is protected by mucus. When this lining becomes erroded by stress, caffine in excess, asprin, nicotine, and alcohol you can develope ulcers. Ulcers are open sores that bleed into the stomach.

Now the chyme leaves the stomach and enters the small intestine. This is where food is digested and absorbed. This tube is approx 6 meters long in adults. The small intestine consists of the duodenum, jejunum, and ileum. The digestion that takes place in the small intestine needs enzymes in which it relys on two sources to recieve these enzymes. The pancreas is one of these sources. It has and encride and exocrine function. The endocrine function is where it releases enzymes to help the food in the small intestine break down. The exocrine function is where it produces and releases insulin and glucagon that regulate blood glucose levels. The pancreas produces 1200-1500 ml of juices that are released into the small intestine.

Next is the liver. This is one of the largest and most versitil organs. It stores glucose, fats and many micronutrients. It also releases them as needed by the body. It also synthesizes blood prtiens that are involed in clotting. The liver produces bile that digests fats. Bile salts also aid in this process. The bile then goes to the gall bladder. Here all the water is removed and the bile is stored until needed. When the bile gets blocked the blockage is know as gall stones. Gall stones are deposits of cholesterol and other materials that block the flow of bile. They often are found in older overweight people and can be removed surgically.

The next is the large intestine. It is approx. 1.5 meters long and has 4 regions. Starting at the small intestine they are the cecum, appendix, colon and the rectum. The cecum is a pouch that is below the junction of the large and small intestine. The appendix is a small worm like structure that attaches to the cecum. Most of the large intestine consists of the colon. The colon is relitively straight and consists of the ascending colon, the decending colon and the transverse colon. From here the colon empties into the rectum. The colon absorbes 90% of water and sodium and after they are absorbed you have the final product which is called feces. Feces is primarily undigested food, indigestible material, and bacteria. When the rectum gets full with fecal matter, it ditends the organ. Then it stimulates the defication reflex. Then nerve impulses travel to the spinal cord. Defication does not occur until the external sphincter relaxes which is why generally we can control this function.

The Circulatory System


www.medem.com/MedLB/article_detaillb.cfm?arti...

One of the bodies chief homeostactic systems is the circulatory system. This system contains the heart, the pump and two circuits which are the pulmonary circuit and the systematic circuit. The pulmonay circuit delivers blood to and from the lungs and the systematic circuit delivers blood to the body and returns it to the heart. The heart consists of four chambers. Two of these are atria and two of these are ventricles. The right ventricle and the right atrium serve the pulmonary circuit and the left venticle and the left atrium serve the systematic circuit and also pump blood into the aorta. When the bllod is returning from the body tissue, it is low in oxygen and rich in carbon dioxide. It is recieved by the right atruim through the superior and inferior vena cavae. This high in carbon dioxide low in oxygen is then pumped into the right ventricle to the lungs where it is resupplied with oxygen and stripped of most of the carbon dioxide. It returns to the heart though the pulmonary vein and emters into the left atruim. Once in the left atrium, it goes to the left ventricle where then it released into the aorta which then pumps it throughout the body to supply oxygen to the tissues and organs and picks up cellular wastes.The heart has an interal pacemaker which is called the sinoatrial node. This node on its own produces 100 contractions per minute. During sress or excersize, the heart rate increases to help keep up with the bodies demand. Also the hearts valves controls the direction of the blood flow through the heart. If electrical activity of the heart muscles change it can be detected by what is called an ECG or otherwise known as electrocardiogram. This is where they can attach electrodes to your body that can detect irregularities through the disruption of the waves.

The blood vessels are what disrtibute blood throughout the body. Blood is ditributed through the body in arteries and returned to the heart in veins. The aorta has many elastic arteries and form muscular arteries that expand and contract with the blood flow. These help the blood as it leaves the heart in the aorta to get pumped to the cappilaries. In the walls of the arteries is a smooth muscle that expands and contracts to a variety of different stimuli that controls the blood flow. Blood pressure and flow rate start out high in the aorta and end up reduced the further it travels to help with the rate of exchange between the blood and tissues. There are many networks or cappilary beds throughout the body system. These help echange wastes and nutrients between the tissue and the capillary network. With the help of gravity the blood above the heart is able to drain but the blood below the heart relies on the body movement to push it up and on the valves there are flaps of tissue that prevent backflow.

The lymphatic ststem is an important function in immune protection. There are several things that help with that including the spleen, lymph nodes, thymus, and tonsils. The lymphatic system also drains excess interstitial fluids from the body tissue and transports it to the blood stream.

Hypertension is high blood pressure that can result in heart attacks and strokes. Often times this elevates over a long period of time and is not noticed until it is critical.

Heart attacks can occur very rapidly or they can happen over a period of time. If it is over a period of time usually a pain called angina is felt and this is when the blood flow is restricted to the heart. The most common heart attack is called myocardial infarction and this is usually caused by a blood clot that eventaully breaks loose and gets lodged in an artery which causes a decrease in the blood flow.

There are many different blood types. Blood consists of two basic components one of which is the plasma. The plasma has dissolved nutrients, rpotiens, gases, and and wastes that for the white blood cells and the red blood cells and platlets. The white blood cells are part of the bodies protective mechanisms that combat microorganisms. They work mainly outside the bllod stream in the tissue and are produced in the bone marrow. The red blood cells are produced by red bone marrow. The blood plasma makes up about 55% of human blood. There is also what is known as platlets. Platlets are needed in the blood clotting mechanisms.