The Circulatory System

Question 1

How many chambers does the heart have

Answer 1

4

Question 2

3 main types of blood vessels

Answer 2

Arteries - blood away from heart
Veins - blood to heart
Capillaries - where the exchange between the blood and the cells takes place

Question 3

Where does the right side of the heart send blood

Answer 3

To the lungs

Question 4

Where does the left side of the heart send blood

Answer 4

Around the rest of the body

Question 5

Blood always flows from a region of what to what

Answer 5

Higher pressure to lower pressure

Question 6

What do valves do

Answer 6

Prevent blood from flowing backwards

Question 7

Do heart valves need energy to work

Answer 7

No it’s the blood pressing on the valve that makes them open and close

Question 8

What is the cardiac cycle (basic)

Answer 8

Sequence of events that occurs during one heartbeat

Question 9

Explain the cardiac cycle

Answer 9

1) blood flows into the two atria
2) the atria contracts to push the blood into the ventricles
3) the ventricles contract forcing blood into the aorta and the pulmonary artery
4) the blood flows down the arteries and leaves the heart. The whole cycle starts again

Question 10

Are the ventricles more powerful than the atria

Answer 10

Yes
The heart valves pop shut automatically

T to prevent back flow into the atria.

Question 11

Why are ventricle walls thicker

Answer 11

They need to push the blood further

Question 12

What happens to valves as soon as the ventricles relax

Answer 12

The valves at the top of the heart pop shut to prevent back flow of blood as the blood in the arteries is now under a bit of pressure

Question 13

What do most muscles require to contract

Answer 13

A nerve impulse from the central nervous system

Question 14

T or f
The heart produces its own electrical impulse

Answer 14

True

Question 15

Where is the hearts pacemaker

Answer 15

A group of specialised cells called the Sino-atrial node in the wall of the right atrium

Question 16

Where does the impulses form the hearts pacemaker spread across

Answer 16

The atria

Question 17

Why does the heart muscle need oxygen and glucose

Answer 17

So it can respite and release the energy it need to function

Question 18

What is the heart muscle supplied with blood from

Answer 18

The coronary arteries

Question 19

What do the two main coronary arteries come of

Answer 19

The aorta

Question 20

T or f
The coronary arteries are thick

Answer 20

False

Question 21

What are arteries subdivided into

Answer 21

Smaller vessels called arterioles

Question 22

What are arterioles subdivided into

Answer 22

Capillaries

Question 23

What do capillaries join up to form

Answer 23

Veins

Question 24

Describe arteries

Answer 24

Thick wall compared to diameter of the lumen

There’s an outer layer of fibrous tissue, them a thick layer of elastic tissue and smooth muscle
E. Then a very thin layer of folded endothelial tissue

Question 25

Explain what happens when the ventricles contract and blood enters the arteries at high pressure.

Answer 25

This stretches the folded endothelium and elastic wal S. When the ventricles relax, it’s the elastic recoil of the artery wall that keeps the blood pressure up. I,portantborgans like the kidneys wouldn’t be able to function if the blood pressure dropped too far between the heartbeats

Question 26

Describe arterioles

Answer 26

Narrower than arteries and they have a high proportion of smooth muscle fingers and a lower proportion of elastic tissue

Question 27

What happens when the circular muscle fibres of an arterioles contract

Answer 27

The diameter of the lumen is reduced so less blood flows through that vessel. This means that arterioles can control the amount of blood flowing into a particular organ

Question 28

Describe a capillary

Answer 28

The waLls consist of a single layer of endothelial cells Some capillaries have tiny gaps between the endothelial cells

Question 29

How are capillaries well suited to thei jobs

Answer 29

They have very thin walls and the gaps between the cells allow water and substances like glucose and oxygen to diffuse quickly from the blood into the cells. Waste products such as carbon dioxide and urea diffuse from the cells into the blood. Organs contain thousands of capillaries so altogether there’s a huge surface area for the exchange of substances Blood flows quiche slowly though capillaries. This allows more time for diffusion to occur

Question 30

Describe the vein

Answer 30

Large lumen and a relatively thin wall containing some elastic tissue and smooth muscle. Veins also have valves that prevent the blood flowing backwards

Question 31

When the leg muscle contracts what happens to the veins

Answer 31

They contract and bulge and press on the walls of the veins, pushing the blood up the veins . When the muscle relax, the valves close. This action helps the blood return to the heart

Question 32

What is the bloods main function

Answer 32

To transport materials to and from the cells

Question 33

Why do red blood cells have haemoglobim

Answer 33

It can carry oxygen

Question 34

What is made when oxygen combines with haemoglobin

Answer 34

Forms oxyhemoglobin