The Digestive System and The Urinary System
The Digestive System and The Urinary System BIO 1004
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This 7 page Bundle was uploaded by Juliane Notetaker on Monday March 28, 2016. The Bundle belongs to BIO 1004 at Mississippi State University taught by Jeffery Echols in Spring 2016. Since its upload, it has received 39 views. For similar materials see Anatomy & Physiology in Biology at Mississippi State University.
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Date Created: 03/28/16
The Digestive System: Mouth: Chemical Digestion: chemical enzymes are used to break down food into smaller particles. Mechanical digestion: grinding food into smaller particles. Structures of the Mouth: Teeth: mastication (mechanical digestion) Grinding food into smaller particles Salivary glands: (Chemical) produce saliva major function: to moisten food to make the swallowing process easier Also contains an enzyme called Amylase (converts carbohydrates into simple sugars. Tongue (skeletal muscle) Major function: Manipulation of the food makes mastication more efficient forms a bolus of the food (bolus: round ball of food/whatever is being eaten) Tongue also begins the swallowing process It forces the bolus into the pharynx Taste: taste buds allow the rejection of unpleasant foods Lips: help to gather food. Cheeks: help keep the food in your mouth. Area’s it passes through: Pharynx: common junction between respiratory and digestive systems. o receives the bolus leads to the Esophagus Esophagus: a tube of smooth muscle that connects the pharynx to the stomach. At the lower end of the esophagus there is a sphincter that prevents the contents of the stomach from moving back into the esophagus. o Peristalsis: rhythmic waves of muscular contractions in the esophagus stimulated by swallowing; moves the bolus through the esophagus into the stomach. (Amylase is still active as the bolus travels down the esophagus) Stomach: made up of smooth muscle found between the esophagus & small intestine sphincters at both ends. is a storage pouch. does contain numerous capillary beds so it can directly absorb water into the blood stream, as well as alcohol o Found in the stomach: hydrochloric acid (HCL) HCL kills bacteria, prevents the contents of the stomach from spoiling, It may start breaking down ligaments and tendons. (PH around 2) Mucus lining: Stomach is protected by a thick layer of mucous. o Pepsin: an enzyme that begins to convert proteins into amino acids o Peristalsis: breaks up the bolus and forms a soupy mixture that is called a chyme o Ulcers: Anything that thins the mucous lining may lead to the development of ulcers The major things that cause the thinning: stress, some spicy foods, certain medications; Ulcers will only develop is a certain bacteria is in the system. An ulcer is a bacterial infection. o Helicobacter pylori: it invades the stomach lining and begins to produce a basic solution o Acid reflux: (heart burn) the sphincter between the esophagus and the stomach weakens allows small amounts of chyme to enter the esophagus. o The acid in pepsin initially stimulates pain receptors; over time it can damage the esophagus Small intestine: where the majority of digestion occurs. Enzymes convert carbohydrates into simple sugars, proteins into amino acids; and fats into glycerol and fatty acids. Capillary beds: absorb simple sugars and amino acids. Over 90% of absorption and digestion take place. Has a corrugated lining covered with fingerlike projections called Vili o The Vili increase surface area making digestion and absorption more efficient. o Each Vili contains a capillary bed for the absorption of simple sugars and amino acids. Also contains a lacteal a small tube connected to the lymphatic system: which absorbs glycerol and fatty acids. The small intestine also produces some digestive enzymes. Function of the small intestine: chemical digestion of larger molecules, absorption of smaller molecules into the blood stream or lymphatic system. Major function: the absorption of water Made up of smooth muscle Chyme is moved through the small intestine by rhythmic waves of muscular contractions called Peristalsis The small intestine connects to the large intestine. Large intestine: Larger than small intestine. Smooth muscle, peristalsis Major function: absorption of water. Minor Function: o absorption of certain vitamins. o Normal flora: bacteria that live in the large intestine. they help to prevent infections. Production of normal flora produce certain vitamins. Terminal end of the large intestine: 68 inches is a holding area for fecal material called the rectum. At the terminal end is a sphincter (anus): a valve that controls elimination Liver: o Largest internal organ o Liver produces bile Bile is stored in the gall bladder released into the small intestine Bile is not an enzyme. Bile is an emulsifying agent. It breaks fat into small droplets, which increases surface area and makes fat digestion more efficient. o Also receives most of its blood directly from the small intestine (hepatic portal system) The liver receives the most nutrient dense blood in the body. o It then stores excess nutrients. o Also maintains a constant level of nutrients in the blood exiting the liver. During development (in utero) the liver is the first organ that produces blood cells. o After birth, the liver recycles older blood cells. o The liver and the pancreas release their products into the upper part of the small intestine. Appendix: Finger like projection at the base of the large intestine. o Part of the lymphatic system. Lymphatic system absorbs glycerol and fatty acids. o Participates in immunity. o Can be “clogged” by small hard particles (seeds, pepper) Pancreas: found between the stomach and small intestine. o Produces amylase, peptidase, and lipase Peptidase: breaks down proteins into amino acids Lipase: fats into glycerol and fatty acids Alkali solution: neutralizes chyme All (amylase, peptidase, and lipase) together is known as Digestive juice. The alkali solution neutralizes the acid from the stomach preventing the destruction of the lining of the small intestine Urinary System: Functions of the urinary system: o Major: Removal of nitrogenous waste from the blood. Nitrogenous waste: waste products that contain nitrogen. o One of the first steps of digesting protein Deamination – removal of amino acid o All cells in the body break down proteins releasing ammonia (NH3) o Liver: first the the ammonia does is travel to the liver. 2(NH3 + CO2)==>Urea o Ammonia is converted to a less toxic substance known as urea. The urea goes back into the blood stream where it is removed by the kidneys. o Controls water balance in the blood (viscositythickness of the blood), how much water you absorb into the blood as it flows through the system. o Control of the pH of the blood o Control of the salt content in the blood Structures: o Macro: Kidneys: are not evenly distributed Filtering apparatus (where the blood is filtered) Kidneys have a huge blood supply entire amount of blood is filtered approximately every 30 minutes. Ureter: have no sphincters; gravity allows urine to travel down the ureter to the urinary bladder. Urinary Bladder: stores urine Urethra: is a tube that drains the urinary bladder. It has 2 sphincters. One: where the urethra connects to the urinary bladder Two: is where the urethra passes through the abdominal wall Osmoregulation: control of the salt/water balance o Microscopic structures of the urinary system: Nephron: distal convoluted tubule Bowman’s Lapsule: pouch Proximal Convulated Tubule: starts behind the Bowman’s lapse Loop of Henle (Loop of nephron) is the loop in the structure Distal Convulated Tubule is after the lood Collecting duct: is long straight end There are 2 capillary beds (really just one) 1st Capillary bed is found in the Bowman’s Lapsule called the Glomerular Capillary Bed o Supplies blood to the filter. 10 times more permeable (leaky) than any other capillary bed. 2nd Peritubular Capillary Bed o Surrounds the tubular system o It absorbs fluids from within the tubular system Urine Formation: 1. Pressure Filtration: o Structures involved: Bowman’s Lapsule, Glomerular Capillary Bed o As blood flows through the capillary bed, most of the plasma leaks out; the fluid is captured by the Bowman’s Lapsul The fluid in the Bowman’s Lapsule is called filtrate. (10x leakier than any other capillary bed) Plasma: 55% of blood H2O Protein Nutrients Hormones Vitamins Urea 2. Selective reabsorption: o Structures involved: Proximal Convulated Tubule, the peritubular capillary bed As filtrate passes through the Proximal Convoluted Tubule, certain components are absorbed into the peritubular capillary bed including: water, protein, nutrients, hormones and vitamins o You can’t absorb all of the water at this point. 2A. As the filtrate passes through the loop of the nephron, water is absorbed into the peritubular capillary bed. There is no control of water absorption at this point. o Water absorption can’t be controlled 3. Tubular Secretion: Structures involved: Distal convulated tubular and the peritubular capillary bed o Unfiltrable waste such as toxin and poisons move from the peritubular capillary bed into filtrate. o The filtrate eventually reaches the collecting duct. If the blood is too vicious, water continues to be absorbed from the filtrate into the blood stream. If the blood is too thin, water is allowed to pass out in the filtrate. The collecting ducts is where the viscosity of the blood is controlled. o The collecting duct serves multiple nephrons and they eventually lead to the ureters. The collecting duct controls everything. o Amine Group: NH3=Ammonia (highly toxic) H20—no energy Requires huge amounts of water to dilute to safe levels. Fish excrete ammonia because they constantly take in water Amphibians can excrete ammonia: Tadpoles Urea: Other ways of excreting nitrogenous waste Liver, less toxic than ammonia. NH3+CO2 Less Toxic requires less water but more energy o Mammals/Amphibians: excretes urea o Adult amphibians excrete urea Uric Acid: almost nontoxic Is a paste, not a liquid Requires very small amounts of water to dilute to a safe level. Huge amounts of energy to produce it Reptiles and Birds excrete uric acid (white stuff in feces)
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