7. Blood flow in veins muscles beside vein contract action of valves blood flows towards heart muscle (contract) valve flaps pushed apart by blood pressure vein is squeezed by muscles valve flaps pushed together by backflow of blood
16. Exchange of materials between the blood and the body cells plasma tissue fluid O 2 nutrients water white blood cells Diffuse across the capillary wall CO 2 waste products Diffuse across the capillary wall Squeeze through the wall oxyhaemoglobin capillary cell
17.
18. Formation of the tissue fluid At arterial end : some materials are forced out of the capillaries high pressure capillary bed body cell red blood cell blood pressure pressure of tissue fluid tissue fluid arteriole tissue fluid
19. Formation of the tissue fluid Tissue fluid is mainly water with some mineral salts, fats, sugars and hormones similar to blood plasma but NO plasma proteins and red blood cells too large to be forced through capillary wall capillary bed tissue fluid
20. Formation of the tissue fluid At venous end : some tissue fluid return to capillaries , others are drained into lymph vessels capillary bed blood pressure pressure of tissue fluid venule lymph
22. Activity: In your groups, come out with a table stating the characteristics of the artery, vein and capillary Use the following table as a template Template Answer
Editor's Notes
Blood pressure and blood velocity drop off in capillaries because capillaries have a greater cross-sectional area than arteries.
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