PSL301: Water 6 Flashcards Preview

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Flashcards in PSL301: Water 6 Deck (75)
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1

sources of dietary potassium

fruits, veggies

2

where is potassium absorbed

100% absorbed from gut

3

K is excreted by...

>90% kidneys (urine)
very small amount in stool

4

Why is K important? (6)

1. most abundant ion in body fluids
2. major intracellular cation
3. determines resting membrane potential of cells (muscle & cardiac function)
4. determine cell's transmembrane potential
5. keep inside cell negative
6. affects peripheral vascular resistance

5

What keeps the cell negatively charged (relating to K)?

K leak out of cells through K channels, which keeps inside the cells negative

6

Rate that K+ leaks out of cell depends on...

concentration

7

Nernst equation

[K]ecf / [K]icf = ratio of K outside vs. inside the cell
- determines cell's transmembrane potential

8

normal serum K+

3.5 - 5 mmol/L

9

K depletion means there is ___ serum K, and the RMP is ___.

too little;
hyperpolarized (less positive than normal)

10

K excess means there is ___ ECF K, and the RMP is ___.

too much;
depolarized (more positive than normal)

11

Hypokalemia: more K+ lost from ECF // ICF

ECF

12

Hypokalemia: Nernst equation change

decrease, since more K is lost from ECF

13

Symptoms of hypokalemia

- muscle weakness
- irregular heart rhythm

14

why do hypokalemic people experience weakness?

Hard to contract muscles due to hyperpolarized state of cells

15

Hyperkalemia: Nernst equation change

Increase, since ECF is more impacted than ICF

16

Symptoms of hyperkalemia

- muscle stiffness & weakness
- abnormal ECG
- life0threatening cardiac arrhythmias

17

Why do hyperkalemics experience muscle stiffness?

cells are depolarized, so muscles are constantly tense

18

which is more life-threatening: hypokalemia or hyperkalemia? why?

hyperkalemia;
bigger effect on cardiac rhythm

19

what kidney treatment do people with hyperkalemia have to go through?

Dialysis;
high levels of K means kidneys have probably failed

20

distribution of K in ECF vs. ICF

ECF: 2%
ICF: 98%

21

Serum K =

ECF K

22

effect of insulin in K

K uptake by cells

23

Insulin deficiency has what impact on K?

cause K to leak out of cells

24

effect of adrenaline binding to B2-catecholamine receptor on K

K uptake by cells

25

Effect of B-blockers on K

cause K to leak out of cells

26

adrenaline binding to _____ receptor causes K uptake?

B2-catecholamine

27

K will leave cells due to ___ stress, such as...
This has detrimental effects on the patient because...

mechanical;
cell death, injury;
hyperkalemia, maybe can't get treatment if crush injury or trapped somewhere

28

What prevents hyperkalemia every time we eat?

- eating stimulates insulin secretion
- insulin promotes muscle cell uptake of K & promotion of secretion in urine

29

Effect of exercise on K

cause K to leak out of cells
- dilation of arterioles
- increase muscle blood flow

30

What prevents hyperkalemia every time we exercise?

adrenaline redistributes excess K in ECF to resting tissue