Question

Describe the key processes in urine formation in a mammalian nephron, beginning with the glomerulus and ending with the excretion of urine from the collecting duct into the renal pelvis.

Answer 1

3main steps in urine formation is

glomerular filtration

tubular reabsorption

tubular secretion

each kidney contain s nephrons . nephrones has a specific structure ,the first part of nephrone is a cup like structure called bowmans capsule . glomerulus present in it glomerulus is a capillary network .when blood flows through it the blood pressure pushes water and solutes from the capillaries to capsule through filtration membrane . this is glomerular filtration . filtration membrane block large proteins . the filtrate flows down through the tubular part of nephron

while it moves through the tube needed substance and some water reabsorbed to adjacent capillaries sodium transported from lumen to blood solutes are reabsorbed isotonically so that the osmotic potential remain same when leaving the pct in collecting duct adh acts and reabsorbes excess water in loop of henle reabsorption of water and sodium take place .it helps to conserve water by counter current exchange

at the same time of reabsorption waste ions and hydrogen ions secreted in to renal tubule .this ions with the filtrate forms urine and it flows in to collecting duct . trhrough renal pelvis it passes to ureter and then to urethra and voided out in pct creatin and uric acid secreated . in dct urea ,pottassium ion and hydrogen ion secreted