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AP Biology Kidney Structure & Function Collecting duct Loop of Henle Amino acids Glucose H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Na + Cl - Mg ++ Ca ++ Na + Cl - Removing Intracellular Waste

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AP Biology intracellular waste Animal systems evolved to support multicellular life O2O2 CHO aa CH CO 2 NH 3 aa O2O2 CH O2O2 aa CO 2 NH 3 O2O2 aa CH aa CHO O2O2 Diffusion too slow! single cell but what if the cells are clustered? for nutrients in & waste out extracellular waste

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AP Biology Overcoming limitations of diffusion Evolution of exchange systems for distributing nutrients _____________________ removing wastes _____________________ systems to support multicellular organisms aa CO 2 NH 3 O2O2 aa CH aa CHO O2O2

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AP Biology Osmoregulation Why do all land animals have to conserve water? always lose water (breathing & waste) may lose life while searching for water Water balance vs. Habitat freshwater ___________________________ water flow into cells & salt loss saltwater ___________________________ water loss from cells land dry environment need to conserve water may also need to conserve salt hypotonic hypertonic

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AP Biology Intracellular Waste What waste products are made inside of cells? what do we digest our food into carbohydrates = CHO lipids = CHO proteins = CHON nucleic acids = CHOPN CO 2 + H 2 O NH 2 = ammonia CO 2 + H 2 O CO 2 + H 2 O + N CO 2 + H 2 O + P + N | ||| H H N COH O R H C Animals poison themselves from the inside by digesting proteins! lots! very little cellular digestion cellular waste

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AP Biology Nitrogenous waste disposal Ammonia (NH 3 ) __________________________ carcinogenic __________________________ easily crosses membranes must dilute it & get rid of it fast! How you get rid of ___________________depends on who you are (evolutionary relationship) where you live (habitat) aquaticterrestrialterrestrial egg layer

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AP Biology Nitrogen waste _____________________ can afford to lose water ___________________ most toxic _____________________ need to conserve water ___________________ less toxic ______________________ ______________________ need to conserve water need to protect embryo in egg ___________________ least toxic

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AP Biology Freshwater animals Hypotonic environment water diffuses into cells Manage water & waste together remove surplus water & waste use surplus water to dilute ammonia & excrete it also diffuse ammonia continuously through gills overcome loss of salts reabsorb in kidneys or active transport across gills

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AP Biology Land animals Nitrogen waste disposal on land need to conserve water must process ammonia so less toxic _______= larger molecule = less soluble = less toxic 2NH 2 + CO 2 = urea _________________________ __________________ filter solutes out of blood reabsorb H 2 O (+ any useful solutes) excrete waste _______ = urea, salts, excess sugar & H 2 O urine is very concentrated concentrated NH 3 would be too toxic O C H N H H N H Urea costs energy to synthesize, but its worth it! mammals

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AP Biology Nitrogen waste disposal in egg no place to get rid of waste in egg need even less soluble molecule ___________ = BIGGER = less soluble = less toxic birds, reptiles, insects Egg-laying land animals itty bitty living space!

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AP Biology N N N N O H O O H H H Uric acid And that folks, is why most male birds dont have a penis! Polymerized urea large molecule ______________________________ doesnt harm embryo in egg white dust in egg adults still excrete N waste as white paste no liquid waste uric acid = white bird poop!

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AP Biology Mammalian System Filter solutes out of blood & reabsorb H 2 O + desirable solutes Key functions ______________________ fluids (water & solutes) filtered out of blood ______________________ selectively reabsorb (diffusion) needed water + solutes back to blood ______________________ pump out any other unwanted solutes to urine ______________________ expel concentrated urine (N waste + solutes + toxins) from body bloodfiltrate concentrated urine filtrate

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AP Biology Mammalian Kidney kidney bladder ureter urethra renal vein & artery nephro n microvilli on epithelial cells adrenal gland inferior vena cava aorta

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AP Biology Nephron Functional units of kidney 1 million nephrons per kidney Function filter out urea & other solutes (salt, sugar) blood plasma filtered into nephron high pressure flow selective reabsorption of valuable solutes & H 2 O back into bloodstream greater flexibility & control counter current exchange system why selective reabsorption & not selective filtration?

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AP Biology Mammalian kidney Proximal tubule Distal tubule Glomerulus Collecting duct Loop of Henle Amino acids Glucose H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Na + Cl - Mg ++ Ca ++ Interaction of circulatory & excretory systems How can different sections allow the diffusion of different molecules? Bowmans capsule Na + Cl -

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AP Biology Nephron: _______________ At glomerulus high blood pressure in kidneys force to push (filter) H 2 O & solutes out of blood vessel BIG problems when you start out with high blood pressure in system hypertension = kidney damage H 2 O & solutes cells & large molecules

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AP Biology Nephron: _______________ Proximal tubule reabsorbed back into blood

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AP Biology Nephron: Re-absorption structure fits function! Loop of Henle ___________________ reabsorbed _________________ structure

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AP Biology Nephron: Re-absorption structure fits function! Loop of Henle ___________________ reabsorbed _________________ structure

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AP Biology Nephron: Re-absorption Distal tubule reabsorbed

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AP Biology Nephron: Reabsorption & Excretion Collecting duct reabsorbed _______________ _______________ excretion

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AP Biology Osmotic control in nephron How is all this re-absorption achieved? tight osmotic control to reduce the energy cost of excretion use diffusion instead of active transport wherever possible the value of a counter current exchange system

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AP Biology Summary why selective reabsorption & not selective filtration?

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AP Biology Any Questions?