1. Where is it filtered?
2. Where is it reabsorbed?
3. Where is it secreted?
4. What's the effect of aldosterone stimulation?
2. Proximal convoluted tubule
3. Cortical portion of the collecting duct
4. Sodium reabsorption; potassium secretion
T/F: K+ acts independently on adrenal cortex because of release of aldosterone by increasing aldosterone secretion.
Know that K+ directly stimulate adrenal cortex to increase aldosterone secretion; however K+ does not directly affect renin secretion, angiotensin II and that whole pathway.
5 mechanisms of control of thirst
1. Baroreceptor response (directly)
Ingestion of water: blood volume, pressure change, baroreceptor input of the brain-hypothalamus
2. Sympathetic nerve activity
Indirectly stimulates thirst by causing an increase in angiotensin, the baroreceptor in the brain will also stimulate an increase in renal sympathetic nerve activity
3. Plasma osmolarity:Osmoreceptors in the hypothalamus
4. Dryness of mouth
5. Extraceullar fluid hypertonicity, dehydration
T/F: Apical membrane of the tubule cells are permeable to bicarbonate ions.
Where is carbonic anhydrase located?
What is alkalosis?
The apical membranes of the tubule cells are impermeable to bicarbonate ions. The enzyme carbonic anhydrase is only found located in the apical cell membrane of the proximal tubule in contract with the filtrate.
During alkalosis, less bicarbonate is reabsorbed and more bicarbonate is excreted to help stabilize the pH.
What is an acidotic condition?
Under acidotic conditions, all of the H+ goes back into the filtrate and is used to hep reabsorb all of the filtered bicarbonate