Urinary final 3 Flashcards
What challenge underlies basic kidney function?
Removal of wastes without removing too much water.
Secretion and absorption rely on active transportation to move molecules. What limitation does this impose on the urinary system?
Transporters can become saturated during times of high solute filtration (after a big meal), so during those times some amino acids or glucose may be expelled in urine
What are the factors (in the nephrone corpusle) can affect glomerular filtration rate
Capillary hydrostatic pressure
Capillary osmotic pressure
What is the volume of glomerular filtrate produced each day? How much is reabsorbed
180 Liters, of which 99% is reabsorbed
What local response to elevated blood pressure would ensure maintenance of normal GFR
Autoregulation- Constriction of gomerular arterioles, particularly the afferent arterioles
Angiotensin 2 activity triggers what two homeostasis promoting events?
- Constriction of peripheral arterioles and capillaries
* Release of aldosterone
Which division of the autonomic nervous system can affect GFR?
Sympathetic
what is countercurrent multiplication?
What two activities ensure it works?
Activity of each branch of the loop of Henle promote the activity of the other branch
•Passive water reabsorption at descending loop
•Active ion reabsorption at the ascending loop
Glomerular filtrate and blood have the same osmolarity. What is this value?
300 mOsM
What happens in the proximal convoluted tubule?
Both water and solutes are reabsorbed, maintaining the starting osmolarity of 300 mOsM
What happens in the descending branch of the loop of Henle?
The ascending branch?
descending branch passive reabsorption of water
Ascending branch- Ion (mostly Na and Cl) reabsorption
What happens in the distal convoluted tubule and the collecting duct?
Final adjustments to the water and ion content
Renin causes the release of what?
angiotensin I
Angiotensin 1 does what?
Angiotensin I converts to angiotensin II
