2.72B understand how the kidney carries out its roles of excretion and osmoregulation

 
Role of Kidney in Excretion:
-Renal Artery will transport oxygenated blood to Bowman's Capsule under high pressure
-Pressure is further increased in Glomerulus due to thinner tubes filtering water, salts, glucose and urea as Glomerular Filtrate
-*Protein molecules: too large, therefore they stay in blood
-The Glomerular Filtrate will enter Bowman's Capsule and into the Tubules
-Glucose is immediately reabsorbed at the Proximal Convoluted Tubule via Active Transport, and the rest of the filtrate will continue through the Tubules
-Salts will be filtered by Loop of Henle depending on water concentrations, and remaining filtrate continues through Tubules
-Water is reabsorbed into blood at Collecting Duct depending on levels of ADH produced (water levels)
-Collecting Duct will collect excess excess filtrates: water and urea, and this will be the urine
-This is transported through Ureter to store in Bladder and removed from the body in the Urethra

Role of Kidney in Osmoregulation:

Low Levels of Water	High Levels of water
-Hypothalamus (in the brain) detects low levels of water in the body	-Hypothalamus (in the brain) detects high levels of water in the body
-Hypothalamus stimulates Pituitary gland to produce more ADH	-Hypothalamus stimulates Pituitary gland to produce less ADH
-More ADH causes membrane of Collecting Duct to be more permeable which results in more absorption of water by osmosis	-Less ADH causes membrane of Collecting Duct to be less permeable which results in less absorption of water by osmosis
-More water is reabsorbed into blood at Collecting Duct	-Less water is reabsorbed into blood at Collecting Duct
-Water level is regulated, urine is concentrated	-Water level is regulated, urine is more dilute

*the role of kidneys in Osmoregulation during low levels of water and high levels of water are directly opposite from each other!