2.69: Understand How the Kidney Carries Out its Roles of Excretion and Osmoregulation

EXCRETION: Removal of Waste Products from Metabolism

OSMOREGULATION: Controlling Water Content in the Body

KIDNEY AND EXCRETION:

ROLE OF KIDNEY IN EXCRETION

Diagram of How Excretion takes Place in the Urinary System and in the Nephron

PROCESS: Renal Artery will Transport Oxygenated Blood to the Bowman’s Capsule under High Pressure Pressure is Further Increased in the Glomerulus Due to Thinner Tubes, Forcing Components Out of the Blood to be Filtered to Produce Glomerular Filtrate: Water, Salts, Glucose and Urea Protein Molecules are Too Large to Enter the Membrane of the Glomerulus so will Stay in the Blood The Glomerular Filtrate will Enter the Bowman Capsule and into the Tubules All Glucose is Immediately Reabsorbed at the Proximal Convoluted Tubule by Active Transport, Rest of the Filtrate will Continue through the Tubules Salts will Be Filtered by the Loop of Henle Depending on the Water Concentrations in the Body, the Remaining Filtrates will Continue through the Tubules Water is Reabsorbed into the Blood at the Collecting Duct Depending on the Levels of ADH Produced (Water Levels in the Body) The Collecting Duct will Collect the Excess Filtrates: Water, Salts and Urea and this will be Urine This is Transported through the Ureter to be Stored in the Gall Bladder and is Removed from the Body through the Urethra

ROLE OF KIDNEY IN OSMOREGULATION

LOW LEVELS OF WATER	HIGH LEVELS OF WATER
Diagram Showing Osmoregulation when Water Levels in the Body is Low	Diagram Showing Osmoregulation when Water Levels in the Body is High
Low Levels of Water in the Body, Hypothalamus Detects this Hypothalamus Stimulates Pituitary Gland to Produce More ADH More ADH causes the Membrane of the Collecting Duct (In Kidney)  to become More Permeable, Allowing More Absorption of Water by Osmosis More Water Reabsorbed into the Blood at Collecting Duct Water Levels in the Body is Regulated, Urine Becomes more Concentrated	High Levels of Water in the Body, Hypothalamus Detects this Hypothalamus Stimulates Pituitary Gland to Produce Less ADH Less ADH causes the Membrane of the Collecting Duct (In Kidney) to become Less Permeable, Allowing Less Absorption of Water by Osmosis Less Water Reabsorbed into the Blood at Collecting Duct Water Levels in the Body is Regulated, Urine Becomes more Dilute