Regulation of fluid compartments and the lymphatic system

Question 1

What is extracellular fluid made up of?

Answer 1

Plasma and interstitial fluid.

Question 2

What is colloid osmotic pressure?

Answer 2

The pressure exerted by the higher levels of protein in the plasma compared with the interstitial fluid - it draws water back into the plasma by osmosis.

Question 3

What is hydrostatic pressure?

Answer 3

Pressure created due to fluid and the force of gravity.

Question 4

What is the volume of interstitial fluid?

Answer 4

12 litres.

Question 5

What is the volume of plasma?

Answer 5

3 litres.

Question 6

What is the volume of intracellular fluid?

Answer 6

28 litres.

Question 7

What can failure of regulation of the bodies fluid result in?

Answer 7

Oedema.

Question 8

What is osmosis?

Answer 8

The net diffusion of water across a selectively permeable membrane from a region of high water concentration to one that has a lower water concentration (low particle concentration to high particle concentration).

Question 9

What is one osmole?

Answer 9

1 mole of solute particles in 1 litre.

Question 10

Is osmolarity dependent on molecular weight?

Answer 10

No.

Question 11

What are the properties of cellular membranes?

Answer 11

They are permeable to water, impermeable to solutes such as Na+, Cl-, K+.

Question 12

What is osmotic pressure?

Answer 12

The pressure required to prevent osmosis. It is proportional to the osmotically active particles in a solution.

Question 13

What is an isotonic solution?

Answer 13

Inside has the same osmotic pressure as outside.

Question 14

What is an hypotonic solution?

Answer 14

Inside has a higher osmotic pressure than outside. (cell swells)

Question 15

What is a hypertonic solution?

Answer 15

Outside has a higher osmotic pressure than inside (cell shrinks)

Question 16

What does the semi-permeable membrane allow diffusion of?

Answer 16

Ions, water, oxygen, nutrients, waste but NOT PROTEINS.

Question 17

What does hydrostatic pressure drive?

Answer 17

Blood from plasma into interstitial space.

Question 18

What is the overall movement across capillary membranes determined by?

Answer 18

Capillary net filtration pressure (NFP).

Question 19

At the arterial end of the capillaries, what pressure dominates?

Answer 19

Hydrostatic pressure - there is net outward filtration.

Question 20

At the venous end of the capillaries, what pressure dominates?

Answer 20

Colloid osmotic pressure - there is net inward filtration.

Question 21

What did William Hunter describe the lymphatic system as?

Answer 21

Present in almost every tissue apart from the brain and that they are essential for the absorption of interstitial fluid.

Question 22

What are the two main functions of the lymph system?

Answer 22

Draining fluid from the tissues and returning to the cardiovascular system, the maintenance of the immune response.

Question 23

What happens to the fluid that passes into the interstitial area and collects in veins?

Answer 23

It passes into lymph capillaries through lymph nodes before passing back to the blood stream at the neck.

Question 24

How does fluid move along the lymph system?

Answer 24

Vessels contain valves and fluid is forced along by the action of muscles and breathing.

Question 25

What cells does lymph fluid contain?

Answer 25

White blood cells such as lymphocytes, macrophages and dendritic cells.

Question 26

How is immunity activated in the lymph system?

Answer 26

The lymph system collects antigens that are recognised by b-lymphocytes in the lymph nodes.

Question 27

What happens to b lymphocytes when they recognise antigens?

Answer 27

The proliferate to produce antibodies.

Question 28

How is oedema caused?

Answer 28

Increased capillary pressure (both ends) and decrease in colloid osmotic pressure

Question 29

What can cause an increase in capillary pressure at both ends?

Answer 29

Heart failure, excessive kidney retention of water, increased arteriolar resistance and a high venous pressure.

Question 30

What can cause a decrease in colloid osmotic pressure?

Answer 30

A reduction in plasma proteins, a loss of proteins in the urine and a loss of protein in the denuded skin areas, malnutrition.

Question 31

What is intracellular oedema?

Answer 31

The depression of metabolic systems of the tissues and lack of adequate nutrition to the cells.