human transport 💗 Flashcards
1
Q
what is function of an artery?
A
carry blood Away from the heart.
2
Q
how does the structure of an artery relate to its function?
A
- small lumen - blood is under high pressure so can flow faster.
- thick muscle/elastic wall - allows artery to stretch under high pressure. muscles can contract to push the blood along.
3
Q
what is the function of a vein?
A
carry blood INto the heart.
4
Q
how does the structure of a vein relate to its function?
A
- large lumen - allows more blood to flow with less vessel resistance. less of a need to maintain high pressure.
- valves - prevent backflow.
- thin muscle/elastic wall - less pressure.
5
Q
what is the function of a capillary?
A
essential for exchange of materials/substances between the blood and body tissues/cells.
6
Q
how does the structure of a capillary relate to its function?
A
- narrow lumen - large S.A:Vol ratio for more efficient exchange.
- cell wall 1 cell thick - short diffusion distance for efficient exchange by diffusion.
