4.1. Regulation of Extra-Cellular Volume

Question 1

What happens as a result of H2O being able to freely cross cell membrane?

Answer 1

The body fluids are all in osmotic equilibrium

Question 2

What percentage of Total Body Weight is fluid?

Answer 2

Fluid = 60% of TBW = 42 litres

Question 3

What is the distribution between Extracellular Fluid, and Intracellular Fluid?

Answer 3

Extracellular Fluid = 14 litres (1/3 of Body Fluid)

Intracellular Fluid = 28 litres (2/3 of Body Fluid)

Question 4

What is the major Osmole controlling Intracellular Fluid?

Answer 4

Potassium Ions (K+)

Question 5

What are the mojor Osmoles controlling Extracellular Fluid?

Answer 5

1. Sodium Ions (Na+)

2. Chloride Ions (Cl-)

Question 6

What is the Extracellular Fluid split up into?

Answer 6

1. Interstitial Fluid = 11 litres

2. Plasma = 3 litres

Question 7

What does a change in the Sodium content of the ECF result in?

Answer 7

A change in ECF volume

Question 8

What does a change in the ECF volume result in?

Answer 8

This effects the volume of blood perfusing the tissues (the effective circulating volume) and blood pressure

Question 9

What is regulation of sodium ion (Na+) dependent on?

Answer 9

High/Low pressure baroreceptors