Flashcards
structure and function of blood vessels
Flashcards do conjunto (7)
- 1Arteries STRUCTUREepithelial 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) - 2Capillaires- 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
- 3Veins1- 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)
- 4Arteries- 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
- 5Capillaires- 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 - 6Veins- 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
- 7effect of faulty valvesthe faulty functioning of valves can contribute to varicose veins and heart failure
Informações
- Descrição
- Eduqas - pg 184-185 theory booklet class - pg 5-6
- Criado por
- Danielle Cope
- Visualizações
- 148
- Avaliação