Flashcards in Potassium Regulation Deck (11):
What is the dietary intake of K per day ?
Where is the majority of K located ?
What is the external K balance ?
Regulation in total K balance through alterations in intake ( dietary ) and excretion ( renal GI ect. )
What is the internal balance of K ?
Distribution of K between the ICV and the ECV
What is the normal renal excretion of K ?
Normal GI excretion
90 - 95 mEq / Day
GI excretion is 5-10 mEq per day
What is the total body K ?
What tissues contain the most K ?
Total Body K is 3300 mEq
Muscle (2500 mEq)
What are the major sites of K secretion ?
Cortical collecting duct. It is dependent on the concentration of aldosterone \.
Principal cells in CCT and outer medullary CT
Where is K reabsorbed ?
The proximal convuluted tubule and TALH. also can be reabsorbed in the inner medullary collecting duct.
What are the effects of aldosterone in the principal cells of the CT ?
It diffuses into the nucleus where it causes upregulation of ...
1. Epithelial Na channel
2. ROMK K+ channel
3. NaKATPase ion pump.
Whare are the factors that effect K secretion ?
1. Concentration gradient of K across the basolateral membrane (Serum K conc)
2. Electrical activity across luminal mem- dependent on the conc. of Na.
3. K+ permeability- Aldosterone concentration