tissue fluid module 3

Question 1

What is plasma?

Answer 1

-straw coloured liquid that is a component of blood
-composed mostly of water
-due to water being good solvent so substances can dissolve in it to be transported

Question 2

How is tissue fluid formed?

Answer 2

as blood passes through the capillaries some plasma leaks out through gaps in wall of capillary to surround cells of body

Question 3

What is the difference between plasma and tissue fluid?

Answer 3

-tissue fluid contains less proteins as proteins are too large to fit through pores of capillary walls

Question 4

What does tissue fluid do?

Answer 4

-bathes almost all cells of body outside circulatory system
-exchanges substances e.g. waste co2 leaves a cell and dissolves into tissue fluid

Question 5

What are the two types of pressures that determine the volume of tissue fluid produced?

Answer 5

-hydrostatic pressure
-oncotic pressure

Question 6

What is hydrostatic pressure?

Answer 6

-pressure exerted by fluid e.g. blood pressure by contraction of heart muscle

Question 7

What is oncotic pressure?

Answer 7

-osmotic pressure exerted by plasma proteins within a blood vessel
-plasma proteins lower water potential within blood vessel causing water to move into blood vessel by osmosis

Question 8

Describe tissue fluid formation at the arterial end

Answer 8

-hydrostatic pressure is great enough to force fluid out of capillary at this end
-proteins remain in blood as too large to pass through pores
-increased protein content creates osmotic pressure between capillary and tissue fluid
-therefore hydrostatic pressure is greater that osmotic pressure so net movement of water out of capillaries into tissue fluid

Question 9

Describe tissue fluid formation at the venous end

Answer 9

-hydrostatic pressure within capillary reduced due to increased distance from heart
-water potential gradient between capillary and tissue fluid is the same as the arterial end
-at venous end osmotic pressure greater than hydrostatic pressure so water flows back into capillary from tissue fluid

Question 10

Diagram of tissue fluid formation

Answer 10

-at the arterial end, hydrostatic pressure is higher than osmotic pressure so tissue fluid forced out of capillaries.
-at venous end hydrostatic pressure drops below osmotic pressure so most of fluid drawn back into capillary.

Question 11

What is lymph

Answer 11

-clear fluid that contains immune cells, waste products instead of blood, remaining tissue fluid that does not enter capillary
-lymph vessels have closed ends and large pores

Question 12

How does lymph reenter blood stream

Answer 12

through veins located close to the heart

Question 13

Difference between tissue fluid and plasma
(3)

Answer 13

-plasma has higher conc of glucose, amino acids, plasma proteins and lower water potential
-tissue fluid has higher conc of substances secreted by celle e.g. insulin