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AQA biology 13.6 blood vessels and their functions
Fichas del conjunto (33)
- 1what do arteries do?carry blood away from the heart into arterioles
- 2what are arterioles and what do they do??smaller arteries that control blood flow from arteries to cappilaries
- 3what are capillaries?tiny vessels that link arterioles to veins
- 4which three vessels share the same basic layered structure?arteries, arterioles and veins.
- 5name the basic structures in blood vessels from the outside inwards.-tough outer layer
-muscle layer
-elastic layer
-thin inner lining (endothelium)
-lumen - 6what is the tough outer layer for in a blood vessel?resist pressure changes from both within and outside
- 7what is the muscle layer for in blood vessels?can contract to control blood flow.
- 8what does the elastic layer in a blood vessel do?helps maintain blood pressure by stretching and springing back
- 9what does the endothelium do in a blood vessel?smooth to prevent friction and thin to allow diffusion
- 10what is the lumen?the central cavity of the blood vessel through which blood flows
- 11what is the muscle layer like in an artery compared to a vein?thick so smaller arteries can constrict and dilate to control the volume of blood passing through them
- 12why is the elastic layer thicker in arteries than veins?-pressure needs to be kept high so blood can reach bodies extremities
-stretched at each beat (systole)
-springs back between beats (diastole) - 13what does the recoil action of the elastic layer in an artery help with?-maintain high blood pressure
-smooth pressure surges from the beating of the heart - 14why is the overall thickness of an artery large?resists the vessel bursting under pressure
- 15are there any valves in an artery?only in the arteries leaving the heart
- 16why are there no valves in most arteries?blood is under constant high pressure so doesn't tend to flow backwards
- 17what are two ways arterioles differ from arteries?muscle layer is thicker and elastic layer is thinner
- 18why is the muscle layer thicker in arterioles?because they contract, causing the lumen to constrict. this restricts blood flow and controls flow into capillaries
- 19why is the elastic layer thinner in arterioles than arteries?the blood is at a lower pressure
- 20what are the 4 main structural features of veins?-thin muscle layer
-thin elastic layer
-overall thickness is small
-valves throughout - 21what are the 5 structural features of capillaries?-walls made of just the lining layer
-numerous and highly branched
-narrow diameter that permeate cells
-lumen is narrow so red blood cells are squished against the side reducing diffusion distance
-spacing between lining cells to let white blood cells esccape - 22capillaries cant serve every cell directly. how does our body counter this?a liquid solution that bathes the tissues. called tissue fluid.
- 23what 5 components does tissue fluid contain?-glucose
-amino acids
-fatty acids
-salts
-oxygen - 24tissue fluid supplies cells with certain substances. what does it get in return?carbon dioxide and other waste materials from the tissues
- 25what is tissue fluid formed from?blood plasma
- 26what is the composition of blood plasma controlled by?various homeostatic systems
- 27blood is pumped through arteries, then narrower arterioles, then narrower capillaries. what kind of pressure does this create?hydrostatic pressure
- 28what does hydrostatic pressure do to blood plasma?forces tissue fluid out of it
- 29what to forces is the outward pressure opposed by?-hydrostatic pressure of tissue fluid outside the capillaries which prevents outward movement of liquid
-lower water potential of blood due to plasma proteins that pulls water back into capillaries - 30the overall pressure is enough to get some molecules out of the capillaries. what is this filtration called?ultrafiltration
- 31how does tissue fluid get back into the capillaries?-loss of t.f. in capillaries reduces hydrostatic pressure inside them
-by the time blood reaches the vein end of the capillary, the pressure in the capillaries is less than the surrounding tissue fluid
-tissue fluids forced back in as pressure outside is greater
-osmotic forces also pull water back into capillaries - 32what happens to the fluid that doesnt return to the capillaries?carried by the lymphatic system
- 33how does fluid move through the lymphatic system?-hydrostatic pressure
-contraction of body muscles
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- AS - Level (unit 2 - 13. exchange and transport) AS Biology Fichas sobre AQA biology 13.6 blood vessels and their functions, creado por Charlotte Hewson el 14/03/2015.
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- Charlotte Hewson
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