Kidney Regulation

ADH Antidiuretic hormone Regulate reabsorption by kidneys Diuretic: promotes production of urine Regulate reabsorption by kidneys Osmoreceptors in hypothalamus Stored in pituitary gland Thirsty Ethanol Osmoreceptor nerve cells in hypothalamus shrink when low water concentration and high solute concentration in bloodstream Shrinking of osmoreceptors cause sensation of thirst Sends signal to pituitary to release ADH ADH causes kidneys to reabsorb more water Distal convoluted tubule and collecting duct permeable to water Water drawn from nephron via osmosis Ethanol is a diuretic Causes more formation of urine Less reabsorption of solutes Can cause dehydration

Blood Pressure Decrease in blood pressure detected by juxtaglomerular apparatus Low blood pressure = reduced O2 Renin released by JGA Converts angiotensinogen to angiotensin Angiotensin Constriction of blood vessels Stimulates release of aldosterone to increase Na+ transport

pH Balance Normal blood pH: 7.35 – 7.45 H+ and HCO3+ Regulate blood pH by the active transport of H+ ions into the filtrate Buffer system CO2 actively transported out of peritubular capillaries CO2 combines with water to form HCO3- or H+ Secretion of H+ ions either slows or increases until the pH returns to normal Excess H+ buffered by bicarbonate ions Urine pH is between 4.5 and 8.0

Kidney Disease Diabetes Mellitus Diabetes Insipidus Type 1 or type 2 Inadequate secretion of insulin from the pancreas results in excess sugar being excreted in the urine Causes excess water loss; constant thirst Diabetes Insipidus Destruction of ADH producing cells in the hypothalamus or the nerve tract to the pituitary gland Large urine output Bright’s Disease (Nephritis) Inflammation of the nephrons Toxins alter the permeability of the nephrons Kidney Stones Precipitation of mineral solutes from the blood Lodge in the renal pelvis and cause pain as they move to the urethra

Homework Have a safe and relaxing Christmas Break!