Biology B3 Blood vessels Flashcards
what is the description for a diagram of an artery ?
Diameter of lumen should be drawn smaller than the vein.
Walls should be thicker than the vein.
what is the description for a diagram of an vein ?
It should be drawn with the widest diameter of lumen.
Wall should consist of a single layer of epithelial cells.
what is the description for a diagram of a capillaries ?
It should be drawn with the narrowest diameter of lumen. Walls should consist of a single layer of epithelial cells.
what is the direction of arteries ?
Arteries are away from the heart
what is the direction of veins ?
veins are towards the heart
what is the direction of capillaries ?
Capillaries are a link between arterioles and venules.
what pressure do arteries have ?
High pressure.
what pressure do veins have ?
low pressure
what pressure do capillaries have ?
Low pressure
what is the diameter of the lumen in arteries ?
Narrow , It also varies between pumping cycles
what is the diameter of lumen in veins ?
wide
what is the diameter of lumen in capillaries ?
Very narrow
what is the wall thickness of arteries ?
Thick
what is the wall thickness of veins ?
Thin
what is the wall thickness of capillaries ?
Very thin permeable walls. One cell thick
do arteries have vales ?
no
do veins have valves ?
Yes , to prevent the backflow of blood
do capillaries have valves ?
No
Describe how the structure fits the function of arteries ?
Arteries carry blood away from the hear at a high pressure . To maintain high pressures between pumping cycles , the walls or arteries are thick and contain elastic fibres.
Describe how structure fits function of capillaries ?
Capillaries are the site of exchange of materials between the body’s tissues and bloodstream.
Capillaries have very thin permeable walls consisting of a single layer of cells reduces the distance for diffusion to occur and increases the efficiency of gas exchange.
Capillaries have a narrow lumen allowing capillaries to fit into small spaces through the body’s tissues.
Describe how the structure fits the function of veins?
Veins carry blood towards the heart at low pressure therefore thick muscular walls are not needed .
Veins have valves to prevent backflow of blood . A wider lumen reduces resistance of blood flow.
