Topic list 4 Flashcards
What are the 3 factors that affect proximal tubule reabsorption?
- Acetazolamide (inhibits carbonic anhydrase)
- Mercury compounds (inhibit aquaporins)
- Non reabsorbed osmolytes (draw water back in the tubule)
What can affect processes in the loop of Henle?
Furosemide, it inhibits the Na+/2Cl-/K+ co transporter
What inhibits the NaCl cotransporter in the distal tubule?
thiazide diuretics
What can enhance Na+ reabsorption in the collecting ducts?
Aldosterone via ENaC expression regulation
What can decrease Na+ reabsorption in the collecting ducts? (2)
- ANP : ENaC inhibition
- Amiloride : ENaC inhibition but spares K+
What cells can be found in the collecting duct? (2)
Principal cells and intercalated cells (alpha and beta)
What is countercurrent multiplication?
A process which creates a gradient for reabsorption of water by the kidneys
What is countercurrent exchange?
A passive process between interstitium and vasa recta that maintains the gradient
Which processes does ATII stimulate? (4)
- Aldosterone synthesis
- Na/H exchange in proximal tubule
- Thirst centres + ADH secretion
- Vasoconstriction
What are the 3 ways to correct LECV?
- Renal sympathetic nerve activity
- ADH / AVP
- ANP
What is buffer base?
amount of strong acid that needs to be added to 1L of fully oxygenated blood in order to restore to standard conditions
Intracellular buffer systems
- hemoglobin
- organic phosphates
Extracellular buffer systems
- bicarbonate
- phosphate
- protein
What is NAE?
Net acid excretion, the total amount of acid excreted in the urine per unit time
NAE=?
NAE = titratable acidity + NH4+ excretion - HCO3- excretion
Starling forces
Forces that combine to drive fluid out of the capillaries into the Bowman space
NUP = ?
(Pc - Pb) - (PIc - PIb)
2 capillary networks of kidney
- glomerular capillaries
- peritubular capillaries / vasa recta
What is tubuloglomerular feedback dependant on?
NaCl
on what receptors do adenosine bind?
A1 receptor, gi coupled
On which cells is A1R?
extraglomerular mesengial cells
Which receptor do we find on afferent and efferent arterioles?
afferent : alpha1
efferent : beta1
4 key paramateres of renal function
- RBF
- RPF
- GFR
- FF (GFR / RPF)
What approximates RPF?
clearance of PAH (para amino hippurate)
What approximates GFR?
- clearance of inulin
- clearance of creatinin
Na+ reabsorption with glucose 2 transporters :
- SGLT
- Glut 2
What does glucose reabsortion with Na do?
causes negative potential in the tubular fluid
What can inhibit Na+ reabsorption with pi, AA?
PTH (parathormone), increase cAMP, inhibits symporter
What is the diluting segment of the loop of henle?
TAL
What does furosemide do?
inhibit 2Cl / K+ / Na+ cotransporter in TAL
Channel in the distal convoluted tubule
Na+ / Cl- co transporter
Receptor for ADH in kidney
V2R (Gs coupled)
Role of alpha and beta intercalated cells
alpha : secrete H+
beta : secrete HCO3-
Osmoreceptors of the CNS (2)
- Vascular organ of lamina terminalis
- Subfornical organ
Which cells synthesize ADH?
magnocellular cells
What is concentrating capacity related to?
Medullary thickness
2 steps of countercurrent multiplication
- single effect
- flow of fluid
Where does ADH increase urea permeability?
at inner medullary collecting duct
What happens when we need to concentrate the kidney? (hyperosmotic urine)
higher ADH level is released
What happens to interstitial osmolarity in the diluting kidney?
it also decreases because urea can’t be reabsorbed
What is the reflex for urination?
micturation reflex
3 muscles for micturition reflex
- detrusor
- internal urethral sphincter
- external urethral sphincter
Sympathetic innervation of bladder
hypogastric nerves
Parasympathetic innervation of bladder
pelvic splanchnic nerve
Somatic innervation of bladder
external sphincter through pudendal nerve
2 phases of bladder
- storage phase
- void phase
What happens during storage phase?
inhibition of parasympathetic fibers
