5105551
Description
Flashcards by Danielle Cope, updated more than 1 year ago
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Created by Danielle Cope
over 8 years ago
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| Question | Answer |
| Arteries STRUCTURE | epithelial cells 1-outer coat (TUNICA EXTERNA) THICK layer of connective tissue-collagen fibres (to resist high pressure and over-stretching) 2- (TUNICA MEDIA) MIDDLE layer of tissue is thick (composed of: smooth muscle, elastic tissue) - arteries SWELL as blood enters and ELASTIC RECOIL helps to maintain the pressure (smaller artrioles have MORE muscles to control flow of blood to capillaries) 3- endothelium (single cell layer to make smooth vessel lining - minimise resistance to blood flow - and short diffusion pathway) surrounded by TUNICA INTIMA 4- LUMEN is narrow ( to maintain pressure) |
| Capillaires | - lined with a SINGLE CELL layer (endothelium) on the basement membrane >site of exchange>short diffusion pathway to the tissue fluid surrounding cells - PORES between the cells make the capillary walls PERMIABLE (water, solutes like glucose) so exchange of materials between the blood and tissues takes place - LUMEN diameter is slightly smaller than a red blood cell so that the ERYTHROCYTES have to squeeze through >slowing flow> allowing more time for diffusion |
| Veins | 1- outer coat (TUNICA EXTERNA) made of connective tissue thinner than in arteries (low pressure) 2- (TUNICA MEDIA) smooth muscle and elastic tissue (layer is smaller than in arteries due to low pressure) 3- endothelium (single cell layer to give smooth lining to vessels reducing friction and minimises resistance to blood flow; and short diffusion pathway) surrounded by TUNICA INTIMA 4- wide LUMEN (so flow of blood is not impeded) |
| Arteries | - carry blood at HIGH pressure - carry blood away from heart - branch into smaller vessels called arterioles that further sub divide into capillaries -BASE of aorta and pulmonary artery - valves |
| Capillaires | - forms a vast network that penetrates all the tissues and organs of the body - LARGE SURFACE AREA for diffusion - blood from the capillaries collects into venules, which take blood into veins, RETURNING it to the heart |
| Veins | - larger diameter lumen than arteries - semi- lunar VALVES prevent back flow - THINNER walls (less connective tissue, muscle and elastic tissue) -carry blood under LOW pressure and lower flow rate -veins above heart (blood returns to heart by gravity) - blood moves through other veins by pressure from surrounding muscle |
| effect of faulty valves | the faulty functioning of valves can contribute to varicose veins and heart failure |
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