3.1 Describe The Structure Of Arteries, Veins and Capillaries
and Relate This To Their Function
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and Relate This To Their Function
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This blog is looking at the structure of the arteries,veins and capillaries and looking at each relate to their function. Our arteries contain a thick wall, the outer wall contains smooth muscle fibres. These muscle fibres contract and relax by way of instruction from the sympathetic nervous system. The inner layer of the arteries is very thin and the tissue is called endothelinal tissue.
The function of the arteries is to move blood away from the heart, they also transport oxygenated blood only, except in the case of the pulmonary artery. Has our ventricles contract, blood goes into the arteries at a high rate, this then stretches the endothelium which is folded and also the elastic walls. Once the ventricles relax it causes the elastic recoil of the wall and that keeps our blood pressure up, so it is important that the arteries are stretchy to allow this action to happen.
The veins outer part have three layers of tissue, the tissue is thinner and less elastical than the arteries layers. The veins also have valves, the valves help in returning blood to the heart, they do this by stopping it going backwards.
The function of the veins is to transport blood to the heart and to also transport deoxygenated blood only, this isn't the case with the pulmonary vein. The veins need to be stronger and thicker to enable the pressure to be kept for the valves to work and for the blood to be transported back to the heart.
Our capillaries are very small blood vessels, they are around 5 - 20 micro metres (ivy-rose web) in diameter. There is capillaries in most of our organs and body tissues. The blood that flows in the capillaries comes from arterioles and are drawn out by venules. The walls aren't very thick, this is so things like water and glucose can be broken down quickly. The venules are even smaller vessels that take blood from the capillaries and to the veins. The function of the capillaries is to supply tissue with components which are carried by the blood. It also helps to get rid of waste from cells that are around, this is beside just moving blood around the body. The capillaries also help in the exchange of oxygen, carbon dioxide, water and salt between the body tissue and the blood. With the capillaries being so small the blood flows slowly, otherwise they wouldn't be able to take the pressure and with the blood flowing slowly it enables longer time for diffusion to take place.
Overall the arteries, veins and capillaries are all different in structure but they all aid in transporting blood around the body and in getting rid of waste.
The function of the arteries is to move blood away from the heart, they also transport oxygenated blood only, except in the case of the pulmonary artery. Has our ventricles contract, blood goes into the arteries at a high rate, this then stretches the endothelium which is folded and also the elastic walls. Once the ventricles relax it causes the elastic recoil of the wall and that keeps our blood pressure up, so it is important that the arteries are stretchy to allow this action to happen.
The veins outer part have three layers of tissue, the tissue is thinner and less elastical than the arteries layers. The veins also have valves, the valves help in returning blood to the heart, they do this by stopping it going backwards.
The function of the veins is to transport blood to the heart and to also transport deoxygenated blood only, this isn't the case with the pulmonary vein. The veins need to be stronger and thicker to enable the pressure to be kept for the valves to work and for the blood to be transported back to the heart.
Our capillaries are very small blood vessels, they are around 5 - 20 micro metres (ivy-rose web) in diameter. There is capillaries in most of our organs and body tissues. The blood that flows in the capillaries comes from arterioles and are drawn out by venules. The walls aren't very thick, this is so things like water and glucose can be broken down quickly. The venules are even smaller vessels that take blood from the capillaries and to the veins. The function of the capillaries is to supply tissue with components which are carried by the blood. It also helps to get rid of waste from cells that are around, this is beside just moving blood around the body. The capillaries also help in the exchange of oxygen, carbon dioxide, water and salt between the body tissue and the blood. With the capillaries being so small the blood flows slowly, otherwise they wouldn't be able to take the pressure and with the blood flowing slowly it enables longer time for diffusion to take place.
Overall the arteries, veins and capillaries are all different in structure but they all aid in transporting blood around the body and in getting rid of waste.
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