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12 Cards in this Set
- Front
- Back
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Describe the general structure of a vessel |
3 layers: tunica intima, tunica media (thick smooth muscle) and tunica externa (connective tissue). Arteries have internal/external elastic membranes in intima & media respectively |
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How are the arteries adapted for their role? |
Arteries carry blood away from heart. Have thick muscular walls so can pump blood to organs and have elastic membranes so they can withstand high pressure blood surges from heart |
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Function of lymphatic vessel? |
Collects excess fluid from blood capillaries & maintains pressure gradient between blood and capillaries. Also absorbs fat. |
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Describe structure/role of veins |
These carry oxygenated blood towards heart. Also found in valves which ensure unidirectional blood flow. Have thin tunica media |
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Describe the role/structure of arterioles |
Arterioles are resistance vessels (they determine and regulate blood flow through them), they only get sympathetic innervation and have small diameter, thin tunica media and externq |
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Describe how capillaries are adapted for their function? |
Capillaries are the site of gas exchange, come in large numbers to inc SA for diffusion, thin walled so short, rapid diffusion pathway |
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What types of capillaries exist? |
Continuous (non-porous so only small, soluble molecules can pass through them). Fenestrated (intima is porous to allow protein exchange) |
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Describe the composition of blood |
55% = plasma (water, nutrients, proteins). 45% = red & white blood cells |
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What are some properties of ereythrocytes? |
They contain no nuclei or organelles. Have life span of 120 days. Obtain energy from anaerobic breakdown of glucose |
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Differences in structure and roles of arteries and veins |
Arterioles have thick tunica media & have elastic membranes, veins don't. Arteries carry deoxygenated blood away from heart. Veins carry oxygenated blood towards heart. |
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Structure of haemoglobin? |
See above |
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Average number of heart beats a day? |
100,000 |
