Biology Test 6 I. NUTRITION

Transcription

1 Biology Test 6 I. NUTRITION A. Process of Nutrition Difference between animal and plant nutrition needs- animals rely on other organisms (Either plants or animals) while plants can produce food/energy on their own. Animals require protein, starch, sugar, lipids, vitamins, and minerals in order in order to make organic compounds while plants solely need light, water, carbon dioxide, and minerals from soil (nitrates and sulphates [protein] and phosphates [Nucleic Acids]) in order to sustain. These differences are important because they cause there to be a food chain, which shapes the way the ecosystem is arranged, and without it there would be a completely shifted and changed world Autotrophs- organisms that obtain energy by making it on their own (i.e.- plants with photosynthesis) Heterotrophs- organisms that obtain energy by consuming other organisms Digestion- conversion of large organic molecules to smaller ones that can be distributed and used Digestion is needed to break down larger organic molecules to smaller ones that can pass through the cell membrane, and to get the building block molecules we need (amino acids [Proteins], glucose and monosaccharides [starch], fatty acids and glycerol [lipid], nucleotides [DNA]) to make the large organic molecules we have to make for our bodies to function (i.e.- human protein, human glycogen, human DNA, human fat) Mechanical Digestion- physically breaking down food, which gives more surface area for enzymes to work. Sites where you mechanically digest- mouth (teeth, tongue, food stays in mouth for 1 minute), stomach Chemical Digestion- use digestive enzymes to break down food

2 II. DIGESTIVE SYSTEM A. Alexis St. Martin set traps for small animals and sold furs, shot a hole in his stomach. Dr. William Beaumont came, brought him back to fort, he recovered, but had a hole in his stomach, so he had to wear a bandage over it, and then realized he could just feed him through the stomach hole and did experiments on it B. Organs in human digestive system (in order): Mouth (mechanical digestion through teeth and tongue and chemical digestion through salivary amylase (breaks starch into maltose) Pharynx- back of throat where food passes through to get to the esophagus Epiglottis- covers trachea Esophagus- food moves down totally due to smooth muscle contractions (smooth muscle- involuntary muscle) which leads to waves which leads to peristalsis (goes down; reverse peris- throw up) Stomach- completes mechanical digestion down to soupy chyme; chemical digestion includes two types of glands- gastric glands secrete enzymes of pepsin, and they digest proteins and break protein down into smaller polypeptide chains, and are made of acid (HCL ph of ). The other type of gland is the mucous glands, which secrete mucous to protect inner stomach wall Small Intestine- stuff moves along by peristalsis, completes chemical digestion, the rest of the small intestine is for getting the nutrients into the blood stream. The small intestine does require a lot of surface area in order for the digests nutrients to be absorbed into the blood capillaries so that nutrients can be carried by the blood to the cells of the body. Surface area can be increased by loops of small intestine, folds of the inner wall of small intestine, villi (finger-like extensions on the folds in the inner wall of the small intestine), and microvilli (finger-like extensions on the cells of the villi) Large intestine- is 5-6 feet long of smooth muscle when unwinded, "large" because the tube has a bigger diameter, does peristalsis (relaxing of muscles that cause waves that push the food through), takes in non-digestible food such as cellulose and turns it into solid waste (the waste is stored in rectum till elimination), absorbs water

3 that was secreted with digestive enzymes (i.e.- salivary amylase, gastric and intestinal juices). If the peristalsis is too fast, it leads to diarrhea, while peristalsis that is too slow leads to constipation. The large intestine also has symbiotic bacteria, metabolizes undigested food and makes vitamins for us (Appendix- no known function for it but thought to be used a long time ago to digest cellulose because we ate a lot of plants back then) C. Glands of Digestive System: Accessory Glands- secrete juices into digestive canal via ducts Salivary Glands- a type of accessory gland that squirts salivary amylase (helps digest starch, lubricates bolus, and kills pathogens) Pancreas- secretes enzymes into small intestine Liver- makes bile which is stored in gallbladder Gastric Glands- secrete enzymes of pepsin, and they digest proteins and break protein down into smaller polypeptide chains, and are made of acid (HCL ph of ) Intestinal Glands- non accessory gland, lay in bedding of intestines, secrete enzymes Mucous Glands- secrete mucous to protect inner stomach wall D. Malfunctions (don't do their job): Ulcers- raw wound- enzymes become overactive and cause raw wounds in stomach and intestines Gallstones- crystallizes salt in bile, which blocks passage of bile from rectum into large intestine

4 III. TRANSPORT A. Structure of Heart: Four chambers- - Right Atrium- receives blood coming from vena cava [deoxygenated] and then squeezes it to the right ventricles - Left Atrium- receives blood from pulmonary vein and pumps it to the left ventricle - Right Ventricle- pumps blood to lungs using pulmonary artery - Left Ventricle- sends blood out to body using the aorta Valves- flaps that prevent back flow of blood - Aortic Valve- between left ventricle and aorta, shaped like a half moon, has 3 cusps - Pulmonary Valve- between right ventricle and pulmonary artery has 3 cusps, shaped like a half moon, opens when the pressure of the right ventricle rises above pressure in pulmonary artery - Atrioventricular Valves (AV Valves- in between the ventricles and the atria)- right AV Valve is tricuspid (3 cusps), Left AV Valve is known as the Mitral Valve B. Cause of heart beat- valves shutting shut, AV Valve is louder. If you hear a "lubstrub" sound instead of a "lubdub" sound, there is a problem with the AV Valve. The pacemaker (AKA Sinal Atrial Node) causes the heart to beat at a certain time. Heart rate can be modified by adrenaline (speeds it up), vagus nerve (slows it down), and accellerator nerve (speeds it up). You don't want your heart to beat too fast because you need the heart to fill before you send out the blood. C. Types of Circulation: Systematic Circulation- left ventricle to aorta, around the body and back to right atrium- carries nutrients to the body Pulmonary Circulation- right ventricle to pulmonary artery to lungs and back to left atrium- gives oxygen to blood Coronary Circulation- blood flow through coronary artery to bring oxygen and nutrients to the heart muscle itself D. Blood Vessels- Functions, Structure, and Challenges:

5 Arteries- carry blood from the heart, pressure is very high. They must withstand high pressure in the blood coming from the heart. They are thick, muscular elastic walls, and they bulge to receive and recoil to push blood forward. They are the secondary pumps. The inner wall is made of smooth, flat cells. The Middle wall is thick muscular elastic fibers. The Artery wall is tough, inelastic tissue to prevent too much bulge. Veins- carry blood back to the heart, pressure is lower than arteries. They must return blood to the heart on very low blood pressure and against gravity. This forces them to get the blood back in them and then push from behind, or else there will be a skeletal muscular tear in the vein. Capillaries- area of exchange of materials with body cells. They must be thin enough to allow materials to diffuse out to the cells (digested nutrients, oxygen), and to allow wastes from the cells to get into the blood to be carried away. So, the walls must be 1 cell thick in order to do this. E. Malfunctions: Heart attacks- blood flow is blocked from the heart muscle- the coronary artery is blocked and the meat muscle is affected from the lack of blood supple, which causes the attack. The attack is very common and dangerous, as it happens in 3 million different cases and kills many people. in order to stop it, you have to shock/physically pound the heart back into rhythm. Atherosclerosis- plaque that build up on inside of arteries of cholesterol and smooth muscle thickening Coronary thrombosis- A clot (cholesterol builds up) can form at the site of the formation, which blocks the artery Embolisms- clot breaks off and is swept downstream and blocks a smaller artery

6 IV. LIVER A. Function in relation to maintaining Homeostasis: Blood leaving the small intestine passes through the liver capillaries before returning to the heart through the vena cava. This blood would fluctuate (rise and fall in amount) in amount of glucose and amino acids it contains, which depends on when you ate and digested your last food. So, when blood passes through the liver, in order to keep the level of nutrients in the blood constant and homeostatic- - The liver stores excess glucose that is in the blood as glycogen (due to the hormone of insulin) - The liver temporarily stores excess amino acids. If they aren't used within a few hours, the liver breaks them down (deamination) to ammonia (poisonous, eventually gets converted to urea so that it can travel through the blood to the kidney so it can be excreted, one drop of it in 2000 blood drops is deadly) and pyruvic acid (used by body as energy in cell respiration) - Urea (which is formed in the liver) enters the blood to be excreted at the kidney When blood passes through the liver many hours after you ate and when there is little glucose and amino acids coming to the liver in the blood from the small intestine- - The liver puts more glucose into the blood by converting the glycogen stores to glucose, which happens because of the actions of the hormone Glucagon - The liver puts more amino acids into the blood by putting the excess ones that are being gored temporarily if they haven't been broken down yet V. KIDNEY A. Function- to control salt and water balance and to get rid of waste. It does this by: Removing excess water from the blood Removing excess salt from the blood Removing urea from the blood B. Structure- there are 2 of them, size of fist, no protection, 1/4 pound each: Nephron- they are tubules that are found in kidneys- each one is made of 1000s of them C. Structures that Enter/Exit Kidney: Renal Artery- blood goes into kidney carrying wastes and a certain amount of water

7 Renal vein- blood comes out of the kidney clean of waste and with the correct water-salt concentration 2 Ureters- carry the urine out of the kidney so they can exit the body (urine- made of salts, urea, and water, which are all wastes that leave the body) Bladder- stores the urine until elimination Urethra- carries the urine from the bladder out of the body D. Nephron in Specific: 1,000,000 of them in each kidney It is a long/winding tubule that begins looking like "Bowman's Capsule"- or like a pushed in balloon The blood capillary sits in and is surrounded by the Bowman's Capsule, which is where the blood that needs to be cleaned meets the nephron that filters the blood. That nephron filters the blood because the blood pressure from the heart pushes most of the molecules from the blood right through Bowman's Capsule- not pushing through the blood cells or blood proteins, which are too big to go across the capillary and nephron walls. This process does seem wasteful in a way, as you are losing good stuff in the blood, such as amino acids, glucose, water, and some salts. After this, the amino acids, glucose, water, and some salts are re absorbed back into the blood at the next sight of the capillaries (amino acids, glucose, some salts- get back in blood by nephron's active transport and the water by osmosis) The bad stuff- urea, excess salts, excess water- are left in filtrate which is in the nephron to exit the body as urine Why does it make sense to throw everything out into the nephron and then pul back the good into the blood? The body has more control that way- controls exactly what it takes back in

8 E. Diabetes: In diabetes, there's sugar in urine. Why? Because some doesn't go back in because too much glucose isn't good for your blood, and all of the bad stuff shows up in the urine. The kidney is doing its job here, but it has a limit to how fast the active transport carriers work in order to absorb the good. is this a good or bad thing? This is a good thing because the body will only take back so much glucose- which is homeostatic. More would mean too much glucose in the blood (which is bad), so this mechanism shows how the body can make sure that there isn't too much of anything in the blood. This is why glucose in urine is an indicator of too much glucose in the blood. This shows that the problem isn't the kidney, but it is actually that the liver isn't storing the excess glucose in the blood, which is because the insulin isn't "telling" the liver to store it