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21 Cards in this Set
- Front
- Back
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Function of excretory system |
1.) Excrete metabolic wastes- from protein and nucleic acid digestion 2.) regulate water and electrolyte balance |
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What is ammonia?
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1.) Excreted by aquatic invertebrates and vertebrates - Surrounding water quickly dilutes ammonia - ammonia- highly toxix |
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What is Urea? |
1.) principal nitrogenous waste product of adult amphibians (terrestrial) and mammals - urea is produced by liver - urea is 100,000x less toxic than ammonia |
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What is Uric acid? |
1.) Poorly soluble and precipitates, forming crystals - uric acid is excreted as paste with little water loss - uric acid is excreted by insects/ birds/ reptiles (White portion of droppings) |
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Vertebrates have ____. & Invertebrates have _____. |
1.) Kidneys 2.) modifications Example: - earthworms- nephridia- 2 in each section - insects- Malpighian tubules - vertebrates- excretory tubules are nephrons |
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Retroperitoneal |
Kidneys -Adipose holds kidney in place |
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Internal Kidney layers |
Outer layer- renal cortex Inner layer- renal medulla -Collecting ducts give medulla striped appearance |
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What is the renal pelvis? |
large cavity in the kidney that receives urine from collecting ducts and is continuous with the ureter |
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What is the Urethra? |
Females- excretory in function only Males- both excretory and reproductive in function |
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Functional units of kidneys is? |
Nephron= about 1 million/kidney
Kidneys= less than 1% body fat but 20-25% of cardiac output goes to Kidneys |
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Renal arteries: |
Transport 1/4 of cardiac output to kidneys -1800 L of blood pass thru kidneys but only 10% of fluid is filtered out -180 L fluid filtered into nephrons/day - 179 L reabsorbed/day - 1 L excreted as urine/day |
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What is located in the renal pelvis? |
Bowmans capsule with glomerulus |
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Which 3 processes does urine formation require to regulate composition of blood? |
1.) Glomerular filtration 2.) Reabsorption 3.) Secretion |
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What is filtration? |
forcing liquids and solutes ( amino acids, urea, vitamins, etc.) thru a membrane by pressure fluid now called glomerular filtrate |
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Glomerular Filtration |
-Most everthing passes thru except blood proteins and blood cells
- Glomerulonephritis causes inflamed glomeruli so blood cells & protein appear in urine |
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BP rates are?
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60 mm Hg in glomerulus 35 mm Hg in ordinary capillary beds |
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What is reabsorption? |
-70% is in proximal convoluted tubules - return of essential molecules to blood into the peritubular capillaries - all glucose, amino acids, and vitamins are reabsorbed |
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Sodium reabsorbed is?
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aldosterone helps with control especially in distal convoluted tubule
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water reabsorbed is?
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-80% reabsorbed in proximal convoluted tubulue - 20% regulated by ADH in distal convoluted tubules and collecting ducts |
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ADH |
Anti-diuretic hormone from the posterior pituitary -When water is low in blood, ADH is produced and increases permeability of membranes in distal collecting ducts so more water is reabsorbed, therefore urine decreases |
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What is secretion? |
controls blood pH especially in distal collecting ducts -low blood pH stimulates process 1.) secretion of H+, ammonia 2.) secretion of K+ (controlled by aldosterone) |
