urinary system Flashcards
what happens at the kidney?
- regulation of water+ion balance
- excretion of nitrogenous waste
what are the steps to accomplish in the kidney?
filtration
reabsorption
tubular secretion
concentration
what is secreted by juxtaglomular cells on arterioles when bp is low, setting off a cascade of events?
renin
what are the keys to filtration?
high glomerular capillary bp
size dependent permeability
how is GFR regulated with a high bp?
constriction of afferent arteriole (cold weather dieresis)
how is GFR regulated with low bp?
- relaxation, dilation of afferent arteriole
- release of renin into blood (tropic hormone-relase of another hormone)
-activation of hormone angiotensin 2
what does the activation of angiotensin 2 do?
-constriction of efferent arteriole
-constriction of peripheral blood vessels over the body
-stimulation of thirst
-stimulates aldosterone, ADH release
where does the bulk of reabsorption occur?
the proximal convoluted tubule
what pumps are used in the PCT?
na/k pump
na/glucose pump
what is tubular secretion?
movement of waste from peritubular capillary (that was missed by glomerular filtration)
what wastes are secreted in tubular secretion?
urea, ammonia, uric acid, bile acid, drug clearance
what is ADH?
anti-diuretic hormone, controls how many aquaporins
where is ADH store and made?
made in the hypothalamus, stored in the posterior lobe of the pituitary gland
what is aldosterone?
controls the amount of na/k pumps (caffeine blocks this)
where is aldosterone stored?
(in response to low bp, hyponatremia, hypercalcimia) store in the adrenal cortex
