test-3 notes - TEST #3 VII. Excretory System A. Gain and...

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TEST #3 VII. Excretory System A. Gain and loss of water and solutes 1. Water and solutes are added by: a. Absorption from liquid and solid foods ---digestive tract. b. Metabolism c. Respiration 2. Water and solutes are lost by: a. Urinary excretion b. Evaporation from respiratory surfaces c. Sweat d. Elimination in feces B. Components of the urinary system 1. Kidneys a. Cortex and medulla b. Filter water and other solutes from the blood c. Return all but 1% to the blood 2. Urine- fluid that rids the body of water and solutes that aren’t needed. 3. Ureter – tubes between the kidneys and the urinary bladder. 4. Urinary bladder- muscular sac that stores urine. 5. Urethra- tube from the bladder to the outside of the body. 6. Kidney stones C. Nephrons (basic functional unit of the kidney) 1. Slender tubules that extend from the kidney cortex down through the medulla 2. At nephrons water and solutes are filtered out of the blood. ---most will be reclaimed in the peritubular cap(tubes found w/in kidneys). 3. Each nephron starts at the Bowman’s capsule. Inside the capsule is a blood filtering unit called the glomerulus. 4. The filtrate leaves the Bowman’s capsule and flows through the rest of the nephron to the proximal convoluted tubule(close to bowmans capsule) to loop of henle to distal convoluted tubule(not as close to bowmans capsule) to the collecting duct. 5. Duct system leads into the kidney’s central cavity (renal pelvis) and then to the ureter. D. Urine formation – urine formed by three processes. 1. Filtration- pressure filters blood by forcing water and solutes out of the glomerular capillaries.(happens in glomerulus/bowmans capsule) -Kidneys process + 1.5 quarts of blood per min. 2. Reabsorption (99% of stuff is reabsorbed, 1% becomes urine) a. solutes and water which move out of the nephron tubules are absorbed into the peritubular capillaries and return to general circulation. b. Antidiuretic hormone- promotes reabsorption of water. -----diabetes mellitus ( sugar diabetes) -----diabetes insipidus-tasteless (can’t produce ADH) 3. Secretion
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a. Solutes from the peritubular capillaries are secreted into the nephron- opposite of reabsorption. Urine is formed from filtration, secretion, and reabsorption. Excretion is how urine goes out 4. Excretion a. Water and solutes that were not reabsorbed, or were secreted into the tubule, flow into the renal pelvis. b. eliminated from the body by the urinary tract. E. Other excretory organs and structures 1.Sweat Glands -release water and some solutes (urea) 2. Large Intestine- removes salts and heavy metals (lead, mercury) from the blood. 3. Lungs – remove CO2, water, and alcohol from the blood – exhaled VIII. Endocrine System A. Hormones 1. Hormones- products secreted into the bloodstream by endocrine glands. 2. Regulate processes such as growth, reproduction, and maintenance.
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This note was uploaded on 05/09/2009 for the course BIOL 2010 taught by Professor Mattkearley during the Spring '09 term at Auburn University.

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test-3 notes - TEST #3 VII. Excretory System A. Gain and...

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