organisation - arteries, veins and capillaries

Question 1

what do arteries carry?

Answer 1

very high pressure blood from the heart to the organs in the body

Question 2

what are the adaptations of arteries?

Answer 2

• very thick muscular walls allowing them to withstand the very high pressure of the blood
• elastic fibres that stretch and recoil

Question 3

how does blood travel through the arteries?

Answer 3

in surges every time the heart beats

Question 4

what do arteries have elastic fibres?

Answer 4

they stretch when surge of the blood passes through and then recoil in between surges keeping the blood moving

Question 5

what happens as blood passes in the capillaries?

Answer 5

substances such as glucose and oxygen diffuse from blood to the cells. carbon dioxide fifes from the cells back into the blood

Question 6

adaptations of capillaries

Answer 6

• very thin walls so diffusion path very short. allowing substances to diffuse rapidly through the cells and blood

Question 7

what is the risk when blood issues travelling from organs back to the heart?

Answer 7

blood is travelling slowly at a low pressure. this means it could stop or even go backwards

Question 8

what is the structure of the veins?

Answer 8

• thin wall as blood is at a low pressures so does not need to be thick
  -contains valves: when blood flowing correct direction they open allowing blood to flow through but when it goes backwards they shut