Describe the structure and functions of the blood vessels

      

Describe the structure and functions of the blood vessels
i. Arteries
ii. Cappilaries
iii. Veins

  

Answers


Isacko
i. Arteries

carry away blood from the heart

carry oxygenated blood except pulmonary artery which takes blood from the heart to lungs for oxygen

have thick, muscular walls

are elastic

have narrow lumen

all these adaptations are required to withstand high pressure caused by heartbeat

ii. Capillaries

link arterioles and venules to arteries and veins

small in diameter to increase pressure resistance for materials to filter out

thin walled as they consist of a single layer of cells to allow diffusion of substances e.g leucocytes to tissues

thin walled to allow presence of intercellular spaces

large number i.e. numerous to provide a large surface area for exchange of materials

have sphincter muscles at the junction of the arterioles and capillaries to control movement of blood into them

lie close to the body for easy exchange of materials

iii. Veins

carry blood back to the heart

all carry deoxygenated blood except pulmonary vein that carries blood from the heart to lungs

have thinner Walls than arteries

have valves to prevent back flow of blood

have wide lumen
Mohaissack answered the question on October 4, 2017 at 14:26


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