RENAL- potassium balance

Question 1

what are the roles of potassium in the body

Answer 1

nerve conduction
muscle contraction
heart function

Question 2

list some sources of dietary potassium

Answer 2

fruit - bananas, avocado, dried fruits
vegetables - not boiled, beetroot, tomato puree
starchy foods - jacket/baked potatoes. chips
snacks - crisps
drinks - coffee, fruit juice

Question 3

define hypokalaemia

Answer 3

<3.5 mmol / L
can be due to:
drugs - diuretics, GI loss, genetic disease, mineralocorticoid excess

Question 4

define hyperkalaemia

Answer 4

> 5.5 mmol/L

can be due to:
drugs - ace inhibitors
CKD/ESKD
genetics 
food ingestion

Question 5

how is a resting membrane potential established

Answer 5

ratio of potassium inside the cells to sodium outside the cells

gradients are established by sodium, potassium pump - transports 2 potassium ions inside the cell and 3 sodium outside the cell with each ATP molecule

depolarisation = K out of the cell and Na into 
repolarisation = K pumped back into the cell and sodium out again to maintain membrane potential

Question 6

outline the effect of hypokalaemia on RMP

Answer 6

hyperpolarisation of the membrane due to altered K+ gradient
a greater than normal stimulus is required for depolarisation of the membrane
skeletal, smooth muscle and nerve cells are effected leading to weakness, impaired nerve signalling, constipation and change in heart beats