Contraction of body muscles / Hydrostatic pressure of tissue fluid
15
How does tissue fluid return to the blood stream?
Via capillaries and lymphatic system
15
Why do substances move into tissue fluid at the arterial end of the capillary?
Pressure inside capillary greater than tissue fluid
15
Why do substances move out of the tissue fluid at the venous end of the capillary?
Pressure outside the capillary greater than tissue fluid
15
Which location as the highest water potential at the arterial end of the capillary?
Tissue fluid
15
Which location has the highest water potential at the venous end of the capillary?
Tissue fluid
15
How does lymph re-enter the blood stream?
Veins near the heart
15
What is the role of the heart in the formation of tissue fluid?
Ventricle contraction produces high hydrostatic pressure
15
Lymphoedema is a swelling in the legs which may be caused by a blockage in the lymphatic system. Suggest how a blockage in the lymphatic system could cause lymphoedema.
Excess tissue fluid cannot be (re)absorbed / builds up
15
High absorption of salt from the diet can result in a higher than normal concentration of salt in the blood plasma entering capillaries. This can lead to a build-up of tissue fluid.
1. (Higher salt) results in lower water potential of tissue fluid; 2. (So) less water returns to capillary by osmosis (at venule end);
15
The hydrostatic pressure falls from the arteriole end of the capillary to the venule end of the capillary. Explain why.
Loss of water / loss of fluid / friction (against capillary lining).