Tissue Fluid

Question 1

What are capillaries the site for?

Answer 1

Capillaries are the site for exchange of substances between blood and the cells

Question 2

How does tissue fluid allow the exchanging of substances in capillaries?

Answer 2

• fluid that is pushed out of the capillaries
• surrounds all cells in the body x provides the environment in which cells exist
• supplies glucose, amino acids, fatty acids, ions and oxygen to tissues
• allows removal of CO2 and waste materials from tissues to blood

Question 3

how does tissue fluid form?

Answer 3

• ultrafiltration of blood plasma (only small molecules can pass across surface of capillaries)
• large molecules remain in blood plasma
• pumping of heart, causes hydrostatic pressure
  artery => arteriole => capillary => venule => vein

Question 4

describe the hydrostatic pressure in capillaries at the arteriole end

Answer 4

• higher hydrostatic pressure in capillaries vs outside capillaries (pressure gradient for tissue fluid out)
• lower water potential of blood vs tissue fluid
• net movement of fluid out

Question 5

describe the exchange of substances that occur between cells and tissue fluid

Answer 5

useful products tissue fluid => cell
waste products
cell => tissue fluid

Question 6

describe the hydrostatic pressure in capillaries at the venule end

Answer 6

• lower hydrostatic pressure in capillaries since tissue fluid has left at the arteriole end
• lower water potential of blood vs tissue fluid (1. plasma proteins remaining in capillary 2. water moved out at arteriole end)
• net movement of tissue fluid back into capillary

Question 7

what is the lymphatic system?

Answer 7

some tissue fluid passes into lymph vessels, lymph has similar composition to tissue fluid but also carries more lipids