Potassium Regulation Flashcards Preview

Organ Systems- Renal > Potassium Regulation > Flashcards

Flashcards in Potassium Regulation Deck (11):
1

What is the dietary intake of K per day ?

100 mg

2

Where is the majority of K located ?

ICV

3

What is the external K balance ?

Regulation in total K balance through alterations in intake ( dietary ) and excretion ( renal GI ect. )

4

What is the internal balance of K ?

Distribution of K between the ICV and the ECV

5

What is the normal renal excretion of K ?

Normal GI excretion

90 - 95 mEq / Day

GI excretion is 5-10 mEq per day

6

What is the total body K ?

What tissues contain the most K ?

Total Body K is 3300 mEq

Muscle (2500 mEq)
Liver (250)
RBC (250)
Bone (200)

7

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

8

Where is K reabsorbed ?

The proximal convuluted tubule and TALH. also can be reabsorbed in the inner medullary collecting duct.

9

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.

10

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

11

What happens to the lumen of the CT when a greater amount of Na is reabsorbed ?

It will create electronegativity which will promote greater K secretion. Greater Na delivery to the distal tubule will promote Na uptake and K secretion.