Human phys 2601 - Ionoregulation PDF

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Ionoregulation...

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Ionoregulation Humans are able to produce concentrated urine The DCT regulates how concentrated the urine can be (ADH in humans) There is the removal of Na+ in the amphibian nephron, hence frog pees out very diluted urine. They can only make urine as concentrated as their blood (no aquaporins) The anatomy of the mammalian kidney is important in the making of concentrated urine. The cortex is the outer region, medulla inner region The connecting ducts in renal papilla collect urine and empty itself in the ureter, then into the bladder then urinated We have the cortical nephron with bowmans capsule; blood at high pressure is squeezed in there. They play a role in filtering blood but they don’t play a role in urine concentration The medullary nephron is where urine is produced; it has the loop of Henle. Fluid goes down then back up the loop of Henle. After the blood is filtered it goes down the loop then goes up again. The blood that returns into the body has to be at normal osmotic pressure (300mOsm) There is a good relationship between the ability of the kidney to make concentrated urine and medullary thickness Smaller organisms and desert aniamls have bigger rmt Medullaty osmotic gradient Countercurrent multiplication (countercurrent exchange)

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If AVP is low, the wall of the collecting duct stays impermeable to the movement of

water. The loop sets up the gradient Reptiles can only produce isoosmotic urine (u:p= 1), while birds can make up to u:p=4 Birds have reverse peristalsis; where they pump the urine back up into the rectum The water is reabsorbed then they pee later Mammals only rely on their kidney Connective transport is the bulk flow of fluids; circulatory systems are pressuredriven bulk flow eg O2, CO2, nutrients, waste, heat, pressure Pressure driven work - glomerular filtration in the kidney Capillary not good at holding pressure; tend to bust. They are leaky Mammalian blood cell has a nuclei Cardiac output = stroke volume * heart rate

Plant movement Heliotropism allows the leaf to alter relationship Diaheiotropicleaf actively tracks sunlight at around noon Faces sun horizontally in the morning Paraheliotropism avoids sunlight, faces the sun vertically Diaheliotropism will outcompete other leaves and would be warmer Glacial buttercup; attracts insect for pollination and on the other hand insects in return gets warm and cozy The cells away from the light elongate faster than the cell exposed to the light, hence they tip towards sunlight Thigmonasty does respond to vibrations and movements If you touch a single hair nothing happens,...