Tissue Fluid Flashcards
1
Q
what is tissue fluid?
A
watery liquid that contains glucose, amino acids, fatty acids, ions in solution and oxygen
2
Q
what does tissue fluid receive?
A
- carbon dioxide and other waste materials from the tissues
3
Q
what does tissue fluid act as?
A
a means by which materials are exchanged between blood and cells
4
Q
what is tissue fluid formed from?
A
blood plasma
5
Q
what does tissue fluid provide?
A
a mostly constant environment for the cells it surrounds
6
Q
how is tissue fluid formed?
A
- blood pumped by the heart passes along arteries, then the narrower arterioles, then capillaries
- pumping by the heart creates a hydrostatic pressure at the arterial end of the capillaries
- this hydrostatic pressure causes tissue fluid to move out of the blood plasma
- hydrostatic pressure of tissue fluid outside capillaries restricts the outward movement of liquid which lowers the water potential of the blood due to plasma proteins that cause water to move back into the lood within capillaries
- this causes an overall pressure that pushes tissue fluid out of the capillaries at the arterial end
7
Q
what is ultrafiltration?
A
the pressure causes small molecules out of the capillaries leaving all cells and proteins in the blood as they are too large
8
Q
how does most of the tissue fluid return back to the circulatory system?
A
returns to the blood plasma via the capillaries
9
Q
what is the process by which tissue fluid is returned to the circulatory system?
A
- loss of tissue fluid from the capillaries reduces the hydrostatic pressure inside them
- when the blood reaches the venous end of the capillary network its hydrostatic pressure is usually lower than the tissue fluid outside it
- tissue fluid is forced back into capillaries by the higher hydrostatic pressure outside them
- plasma has lost water and contains proteins, so has a lower water potential than tissue fluid
- water leaves the tissue by osmosis down a water potential gradient
