Question

give the sequence of events takes place during physiology of urine formation

Answer 1

Dear student, Urine Formation Involves 3 basic steps: Glomerular filtration Re-absorption Secretion Glomerular filtration Kidney filters 1100−1200 mL blood/min Filtration of blood occurs as it passes through three layers. Endothelium of glomerular blood vessels Epithelium of Bowman’s capsule Basement membrane between these two layers Epithelial cells of Bowman’s capsule are called podocytes. Arrangement of these podocytes leaves extremely minute spaces called filtration slits or slit pores. Ultrafiltration occurs through these slits pores, i.e., all plasma components (except proteins) get filtered into the lumen of the Bowman’s capsule. Glomerular Filtration Rate (GFR): 125 mL/min or 180 L/day The glomerular filtration rate is regulated by the juxta glomerular apparatus which releases the hormone renin. Re-absorption GFR = 180 L/day; Urine released = 1.5 L/day. Thus, 99% of filtrate is re-absorbed by the renal tubules. Re-absorption occurs through the epithelial cells of the various segments of the nephrons. Active Re-absorption: Glucose, Na+, amino acids Passive Re-absorption: Nitrogenous waste, water Secretion Tubular cells secrete substances such as H+, K+ and ammonia into the filtrate. Importance: Maintenance of ionic and acid-base balance of body fluidsRegards.