Renal Phys ML: 9 Flashcards
What is the intracellular concentration of K+
150mM
How is the intracellular concentration of K+ controlled?
through the Na/K ATPase pump
What is the extracellular K+ concentration?
5mM
How is the extracellular concentration of K+ controlled
by the kidneys
What can small changed in K+ concentration cause?
lethal malfunction of excitable tissues
What is hypokalmia
low K
What is hyperkalemia
high K+
Why is the resting mV lower with hypokalemia
lower ECF K+ concentration so it makes the gradient bigger and when K+ moves out more negative ions on membrane which makes the membrane more negative
Why is the resting mV higher with hyperkalemia
higher ecf K+ concentration so it makes the gradient smaller and so when K+ moves out of the cell there is less negative ions on membrane so it becomes more positive (depolled cell at rest)
What renal processes does K+ experience?
All 3:
- filtration
-reabsorption
-secretion
How is K+ reabsorbed
by the paracellular route
- K+ follows water which follows Na+
Where is K+ 65% reabsorbed and non regulated
in the proximal tubule
Where is K+ reabsorbed
proximal tubule and ascending limb
What regulates K+ secretion
aldosterone because it builds pumps and channels
What is the major function of the glomerulus/bowman’s capsule?
forms ultrafiltrate of plasma
What are the controlling forces of the glomerulus/bowman’s capsule?
starling forces
What are the major functions of the proximal tubule
-bulk reabsorption of solutes and water
-secretion of solutes (except K+) and organic acids and bases
What are the controlling factors of the proximal tubule
active transport of solutes with passive water reabsorption
Loop of henle functions
establsihed medullary osmotic gradient and secretion of urea
Descending limb function
bulk reabsorption of water
Descending limb controlling factor
passive water reabsorption
Ascending Limb function
reabsorption of Na+ and Cl-
Ascending limb controlling factor
active transport driving reabsorption by cotransport
Cortical collecting duct function
fine tuning of the reabsorption/secretion of small quantities of useful solutes remaining
Cortical collecting duct controlling factor
aldosterone stimulates Na+ reabsorption and K+ secretion
Cortical and medullary collecting ducts function
fine tuning of water reabsorption and reabsorpton of urea
Cortical and medullary collecting ducts controlling factor
vasopressin increases passive reabsorption of water
