BIO-Urinary System PDF

First Year End Review Urinary System Location of Kidney:Retroperitoneal, Level with and posterior to stomach and pancreas. Level with T12-L3 The Nephron:Functional units(About 2.2 million) of urinary system(filters nitrogenous waste from blood), Form urine...

First Year End Review Urinary System Location of Kidney:Retroperitoneal, Level with and posterior to stomach and pancreas. Level with T12-L3 The Nephron:Functional units(About 2.2 million) of urinary system(filters nitrogenous waste from blood), Form urine. Remove excess water and electrolytes. Renal arteries take blood into kidneys, Renal veins take blood away from kidneys Afferent arterioles take blood into individual nephrons (specifically into individual glomeruli) Efferent arterioles take blood out of individual nephrons (specifically away from individual glomeruli) Glomerulus-Ball of capillaries that filter substances out of blood and into Bowman’s capsule. Then filtrate passes through Proximal convoluted tubuleàLoop of HenleàDistal convoluted tubuleàCollecting duct. Most water, ions will be reabsorbed. RBCs, WBCs, Platelets, Plasma proteins (albumin) do not filter out of the glomerulus. These items are too big to filter out. They remain in the blood and should not be in the urine. What Happens in each part: Proximal Convoluted Tubule (PCT): 65% of water, ions, bicarbonate, H+ is reabsorbed 100% of glucose and amino acids will be reabsorbed (so this means glucose and amino acids should not be in urine) Descending Loop of Henle: Water reabsorption only Ascending Loop of Henle/Early DCT:Solute(i.e. sodium) reabsorption only Late DCT/Collecting Duct: Fine tuning. Reabsorption occurs according to bodily needs What hormones are important here? ADH causes increased water reabsorption in late DCT/Collecting duct Aldosterone causes increased sodium reabsorption in late DCT/collecting duct Where Does Urine Go after Collecting duct? Urine will go into renal pelvis then into ureters then to UB and finally out urethra