B4 - BLOOD VESSELS (Missed out)

Question 1

What are arteries ?

Answer 1

-They carry very high pressure blood form the heart to the organs in the body .

Question 2

One adaptation of the arteries ?

Answer 2

-Arteries have very thick muscular walls , this allow them to withtand the very high pressureo f the blood .

Question 3

Another adaptation of the artieres ?

Answer 3

-Blood travels through the arteries in surges , everytime the hear beats . (Felt in wrists ) .
-To cope with that , elastic fibres strench when the surge fo the blood pushes through nd hten recolis between the sugres which keeps the blood moving .
-Once in the organs , blood flows through the cappilaries .

Question 4

What are the capillaries ?

Answer 4

-When the blood passes through the capilaries , substances such s glucose nd oxygen diffuse from the blood to the cells .
-Carbondioxide diffuses from the cells , back to the blood .

Question 5

Adaptation of capillaries ?

Answer 5

-Capillaries have very thin walls , so he diffusion path isvery short.
-This allows substances to diffuse rapidly beween the blood and body cells .

Question 6

Where does the blood go after the cappilaries ?

Answer 6

-Once the blood psses thorhg the organs , it now makes it way back to he heart in the veins .
PROBLEM - the blood is now traveling slowly at low pressure , meaning that blood oculd stop or evene g backwards .

Question 7

Adapations of veins ?

Answer 7

-Vein shave thin walls ,t he blood pressure is low , so walls do not need to be thick .
-Many veisn contain VALVES , the jobs of the valves is to stop blood flowing backwards .

Question 8

Explanation on how the valves work ?

Answer 8

-When the blood is flowing int he correc direction , the valves are open , allwoing the blood htoruhgh .
-When the blood starts flowing backwardws - the valves start to SHUT .