Basic electrolytes

Question 1

What are the main basic electrolytes in the body?

Answer 1

Sodium - main extracellular cation
Potassium - main intracellular cation
Chloride and bicarbonate - main extracellular anion

Question 2

What determines these concentrations?

Answer 2

The amount of sodium and water in the plasma

Question 3

What will an increase in extracellular fluid osmolarity stimulate?

Answer 3

ADH, causing the body to retain water as an increased osmolarity happens due to dehydration

Question 4

ADH regulates water, what regulates sodium?

Answer 4

The renin-angiotensin-aldosterone system

Question 5

What are the clinical features of water overload?

Answer 5

Confusion, headache, excessive polydipsia, cortisol deficiency and in extreme cases coma. Syndrome of inappropriate ADH secretion (SIADH) can cause water overload

Question 6

Describe hypotonic, hypertonic and isotonic

Answer 6

Hypotonic - loss of electrolytes, in particular, sodium
Hypertonic - loss of water
Isotonic - equal loss of both electrolytes and water

Question 7

How is sodium lost from the body?

Answer 7

It can not be lost without water, either isotonically in the plasma or hypo-tonically in the urine. It has 3 main routes it can be lost in, kidneys via aldosterone therapy and diuretic therapy, GI tract via vomiting and diarrhoea, or the skin via widespread dermatitis, cystic fibrosis and burns