Renal Phys--> K+ Flashcards Preview

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Flashcards in Renal Phys--> K+ Deck (18):
1

what are the 2 purposes of K+?

Cell metabolism
Resting membrane potential

2

What are some truths about K+?

3000-4000 mmols of total storage
- 50-55mmol/Kg
- 95% intracellular

3

What are things that regulate K+?

1. Insulin
2. Catecholamines
3. Aldosterone

4

What are some other factors that regulate this pump?

plasma K+
exercise
cell breakdown
chronic dz

5

How does insulin regulate K+?

Upregulates Na/k ATPase
- alleviates sharp rise in K+ after eating
- promotes skeletal and muscle uptake

6

How do Catecholamines regulate K+ and how?

B2 receptor stimulates Na/K ATPase
- No evidence that K+ releases Epi or NE

7

How does an increase in pH affect K+?

alters K+/H transporter.
- H is taken up by cells in exchange for K+
- Thus leads to serum hyperkalemia

8

How does tonicity affect K+?

during high glucose levels water leaves cell
- K + follows

9

What can be given to take someone out of Sine wave rhythm? What causes this?

Hyperkalemia is the cause
- Insulin
- Catecholamines
- Calcium

10

What is the Segmental control of K+ in the kidney?

proximal tubule- 50-65% absorption (mostly tight juctions)
TAL- 25% absorption
Principal cell- 10% leaving

11

What are some stimulators of K+ excretion?

1. Increase Na delivery to distal tubule
2. Increased flow rates
3. Plasma levels of K+
4. Aldosterone

12

What are the affects of aldosterone on the kidney?

Increase ENAC
increase ROMK
Increase Na/K ATPase expression

13

Where is the BigK channel found? Usually open or closed?

Apical membrane
usually closed

14

What affect does aldosterone have on ROMK?

Increases amount of ROMK embedded into apical membrane

15

When is aldosterone increased? Leads to what?

Increased K+
Increased flow

Leads to increased K+ excretion

16

What does AgII do to ROMK?

Blocks it

17

What are the 3 ATPase pumps?

1. Na/K
2. K/H
3. H+

18

What type of cell can resorb K+?

A and B intercalated cell
- at the expense of H+ excretion
- also needs Hc02 absorption