Blood vessels

• 1. Arteries carry blood from the heart to the rest of the body. Their walls are thick and muscular and have elastic tissue to stretch and recoil as the heart beats, which helps maintain the high pressure. The inner lining (endothelium) is folded, allowing the artery to expand — this also helps it to maintain the high pressure. All arteries carry oxygenated blood except for the pulmonary arteries, which take deoxygenated blood to the lungs.
• 1. Arteries branch into arterioles, which are much smaller than arteries.Like arteries, arterioles have a layer of smooth muscle, but they have less elastic tissue. The smooth muscle allows them to expand or contract, thus controlling the volume of blood flowing to tissues.
• 1. Arterioles branch into capillaries, which are the smallest of the blood vessels. Substances like glucose and oxygen are exchanged between cells and capillaries, so they're adapted for efficient diffusion, e.g. their walls are only one cell thick.
• 1. Capillaries connect to venules, which have very thin walls that can contain some muscle cells. Venules join together to form veins.
• 1. Veins take blood back to the heart under low pressure. They have a wider lumen than equivalent arteries, with very little elastic or muscle tissue. Veins contain valves to stop the blood flowing backwards. Blood flow through the veins is helped by contraction of the body muscles surrounding them. All veins carry deoxygenated blood (because oxygen has been used up by body cells), except for the pulmonary veins, which carry oxygenated blood to the heart from the lungs.
• Label:

  A) elastic tissue in wall

  B) thick muscle layer

  C) lumen (space in centre)

  D) folded endothelium

  
• Label:

  A) endothelium (one cell thick)

  
• what are the components of blood?

  erythrocytes, white blood cells, platelets, and plasma.
• What are the five blood vessels?

  • arteries
  • arterioles
  • veins
  • venules
  • capillaries
• Elastic fibers contain keratin and collagen
• Arteries have a lumen, endothelium, elastic fibers, smooth muscle and collagen fibres
• Arteries have a narrow lumen; high pressure
• Arteries are highly elastic to expand and recoil
• Arteries have a thin muscular wall to withstand the high force
• Arteries have more elastic fibres
• Arteries have no valves (except aortic and pulmonary semilumenar at start ) as they are already high pressure
• Arteries contain oxygenated blood ffrom the heart, except thre pulmonary artery
• Arteries have pulsatile blood flow (expansion and recoil)
• In arteries have a high pressure so the pulse can be felt
• Arteries have 3 layers
• Arteries have a high pressure
• Arteries have a further diffsion distance
• Arteries have an inner layer called the inner endothelium made of squamous cells
• Arteries have smooth muscle to reduce friction
• Arteries have a middle layer called the tunica media, containing smooth muscles cells, collagen and elastic fibres
• Arteries have an outer layer called the tunica externa, containing elatic fibers and collagen
• Veins have a lumen, endothelium, elastic fibers, smooth muscle and collagen fibers.
• Veins have a wide lumen; low pressure
• Veins have a thin wall - less elastic and less muscular
• Veins have valvles (semilunar) preventing backflow
• Veins carry deoxygenated blood to heart from tissues, except the pulmonary vein from the lung
• Veins are non-pulsatile- smooth flow of blood
• Veins carry blood back to the heart
• In the veins blood is at a low pressure and the walls dont need to be thick
• In the vein the lumen is relativly large lumen to ease the flow of blood
• In the veins the walls have a thinner layer of collagen, smooth muscles and elastic tissue. They dont need to strech and recoil. they are not activly constricting.
• Valves open and close because of contracting muscles
• The capillaries have a lumen, endothelium.
• Capillaries are described a leaky
• In capillaries erythrocytes fit through in a single line