Blood
- Created by: Eleanor Izzard
- Created on: 16-12-12 14:59
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- Blood
- Circulatory Systems
- Open
- blood is not always in the blood vessels, it can circulate through the body cavity
- some organs and tissues are bathed in the blood
- action of body muscles can help to circulate the blood or a muscle acts as a pump
- muscle can be a long, muscular tube that blood enters through pores called ostia
- heart pumps blood towards head by peristalsis
- at the forward end of the heart the blood pours out into the body cavity
- heart pumps blood towards head by peristalsis
- muscle can be a long, muscular tube that blood enters through pores called ostia
- works because insects such are small enough that the blood does not have to travel far
- insects do not rely on the blood to transport oxygen and carbon dioxide, they have a separate transport system for this
- blood is not always in the blood vessels, it can circulate through the body cavity
- Closed
- blood is always in the blood vessels
- Tissue fluid bathes the tissues and cells
- enables the heart to pump the blood at a high pressure so that it flows more quickly
- can deliver oxygen and nutrients more quickly and remove CO2 and other wastes more quickly
- rely on the blood to transport O2 and CO2 so the pressure needs to be high to maintain speed
- blood is always in the blood vessels
- Open
- Vessels
- Arteries - away from the heart
- blood is at a high pressure so the artery wall must be able to withstand the pressure
- narrow lumen to maintain pressure
- wall contains elastic tissue that allows the walls to stretch and then recoil as the heart pumps - felt as a pulse when arteries are close to skin
- recoil maintains high pressure whilst the heart relaxes
- thick wall containing collagen (fibrous protein) to give strength - withstand pressure
- wall contains smooth muscle that can contract and constrict the artery
- constriction narrows lumen - used to limit blood flow to certain organs/tissues so it can go else where
- endothelium is folded and can unfold when the artery stretches
- Veins - into the heart
- blood is at a low pressure
- wide lumen to ease passage of blood
- walls have thin layers of collagen, smooth muscle and elastic tissue
- do not need to stretch and recoil and are not actively constricted to reduce blood flow
- contain valves to stop blood flowing in the wrong direction and into the heart
- as the walls are thin the vein can be flattened by the action of the surrounding skeletal muscle
- pressure is applied to the blood, forcing it along in a direction dictated by the valves
- as the walls are thin the vein can be flattened by the action of the surrounding skeletal muscle
- blood is at a low pressure
- Capillaries
- narrow lumen - same width as 1 red blood cell(7 micro metres) so they are squeezed as they pass through them
- helps them to give up their oxygen as they are pressed close to the wall, reducing diffusion distance
- 1 squamous cell thick to reduce diffusion distance of materials between blood and tissue fluid
- narrow lumen - same width as 1 red blood cell(7 micro metres) so they are squeezed as they pass through them
- Arteries - away from the heart
- Circulatory Systems
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