2.5 structure and function of blood vessels

Question 1

what is the function of the elastic fibres in arterial walls

Answer 1

they stretch, pulsate and recoil to accommodate the surge of high pressure blood following the contraction of the heart.

Question 2

state the layers of the arterial wall

Answer 2

central lumen, endothelium, smooth muscle containing elastic fibres and connective tisue containing elastic fibres

Question 3

what is vasodilation

Answer 3

The relaxation of the smooth muscle to increase the diameter of the central lumen to increase blood flow to the capillaries

Question 4

what is vasoconstriction

Answer 4

The contraction of the smooth muscle to narrow the central lumen decreasing blood flow to the capillaries

Question 4

Describe 3 differences between arteries and veins

Answer 4

Central lumen - Thicker in veins than arteries dur to amount of blood.
muscular wall - arteries is thicker due to pressure of blood.
elastic fibres - artery walls are more elastic to allow pulsate, stretch and recoil to accommodate surge of blood.
veins have valves to stop backflow of blood.

Question 5

what does tissue fluid supply cells with

Answer 5

Glucose, oxygen and other substances

Question 6

what happens to excess tissue fluid

Answer 6

it is absorbed by lymphatic cells and becomes known as lymph. After lymph goes through the lymphatic system it is returned to the circulatory system.

Question 7

Describe the function of capillaries.

Answer 7

They allow the exchange of substances between the blood and body’s cells by diffusion through their thin walls (1 cell thick)