BIOL 460 1st Edition Lecture 31 Outline of Last Lecture I Acid base Balance continued II Urinary System a Kidney i Nephron III Glomerular Filtration Outline of Current Lecture I Regulation of Glomerular Filtrate II Reabsorption of Na and Water III Loop of Henle IV ADH V Aldosterone VI Renal acid base balance Current Lecture Regulation of Glomerular Filtrate 1 Exterior a Done by sympathetic division of ANS i Causes vasoconstriction of afferent arterioles b If there is blood less fight or flight conserve blood volume and keep blood pressure high as possible 2 Intrinsic a Renal auto regulation b Macula densa i Detects absorption increase of GFR by detecting increase in number of Na ions in the filtrate ii Secretes adenosine 1 Activates afferent arteriole iii Also inhibit granular cells of SGA from secreting renin These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Reabsorption of Na and H2O from Filtrate 1 180 L of ultrafiltrate produced 2 2L of urine 3 Salt reabsorption by active transport 4 Water needs a concentration gradient a Osmosis 5 Proximal convoluted tubule reabsorbs 2 3 of water and salt in filtrate a Basal surface of PCT i Na K pump 1 Na out K in b Hypertonic water follows salt i Diffuse into cytoplasm then tissue spaces and back into blood c CO2 transport can also occur i Glucose ii Can also pump protons into filtrate via antiport d Remaining 15 is hormonally controlled i Presence or absence of ADH and aldosterone Loop of Henle 1 Create osmotic gradient a Pump salt from filtrate into medulla where it accumulates b Concentration gradient draws water in medulla 2 Perform countercurrent multiplication a Ascending limb is driving force b Salt is pumped out into tissue space of medulla by active transport like cells of PCT i This salt doesn t go into bloodstream 1 PCN vasa recta traps slat ii Cell of limb are impermeable to water so filtrate gets diluted 3 Vasa recta of PCN parallel to LH a Takes water from medulla and returns it to bloodstream but salt gets trapped in medulla i Countercurrent exchange ADH 1 Presence when blood is too salty a Acts on cells of collecting duct and triggers to insert aquaporins into membrane of collecting duct 2 Absence a Aquaporin kept inside b Collecting duct impermeable to water Aldosterone 1 Presence a All of salt is reabsorbed 2 Absence a Slat will remain in ultrafiltrate b Causes reabsorption of salt and excretion of K in urine Renal Acid Base Regulation 1 Kidneys help present pH change by secretion of protons into ultrafiltrate a Urine is slightly acidic pH 5 7 2 CO2 H20 H2CO3 H HCO3 3 By way of filtration 4 Via antiport uphill movement of protons into ultrafiltrate 5 Alkalosis a Increase in pH i Cells pump fewer protons into ultrafiltrate by AP
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