2.3 highways and byways

Question 1

in the arteries, where\from where does blood flow? how?

Answer 1

away from the heart. because of the force of the heartbeat

Question 2

what do arteries must be capable of?

Answer 2

handling the high pressure with which the heart pumps the blood away

pumps = שואב

Question 3

what do arteries have because of high blood pressure?

Answer 3

thick elastic walls made of muscle tissue

Question 4

What happens to the blood when entering the veins? What does it cause?

Answer 4

When blood enters the veins it has much lower pressure than the blood in the arteries. That’s why veins are less muscular but wider.

Question 5

how does the blood keep flowing towards the heart and does not fall back under low pressure?

Answer 5

The veins are equipped with one-way valves.

Question 6

What are the vein’s one way valves similar to?

Answer 6

the valves inside the heart.

Question 7

What do the valves do when blood tries to flow backwards?

Answer 7

They close

Question 8

What is the blood flow in your veins also helped by?

Answer 8

Your skeletal muscles

Question 9

What happens when your skeletal muscles contract?

Answer 9

the veins inside them are squeezed and blood moves towards the heart

Question 10

what is your left atrium connected to?

Answer 10

your pulmonary veins

Question 11

what does your right atrium connect with?

Answer 11

the superior vena cava and inferior vena cava

Question 12

what does the superior vena cava do?

Answer 12

returns blood from your head

Question 13

what does the inferior vena cava do?

Answer 13

returns blood from your abdomen and lower body

Question 14

Can blood be forced to flow in the wrong direction?

Answer 14

no

Question 15

are arteries and veins connected to each other? if yes, how?

Answer 15

Yes, By tiny blood vessels called capillaries.

Question 16

What’s the pressure inside capillaries?

low or high

Answer 16

Very low

Question 17

How thick are the walls of capillaries?

Answer 17

just one cell layer thick

Question 18

Are capillaries narrow or wide?

in diameter

Answer 18

very narrow. about 0.001mm in diameter

Question 19

what do you see when you look at the corners of your eyes?

Answer 19

the capillaries as tiny red lines on the sclera

Question 20

what happens because the walls of capillaries are so thin?

Answer 20

oxygen, water and nutrients easily flow out of them and into the tissues and cells that srronds them

Question 21

how are carbon dioxide and wet removed?

Answer 21

they flow out of the cells and into the capillaries