Body Systems - 3.3 Circulation

Question 1

What does your circulatory system consist of?

Answer 1

• Heart (engine room, pumping continuously to keep blood moving)
• Blood vessels
• Blood

Question 2

Why are the blood vessels important?

Answer 2

Blood carries all materials needed by the body through the blood vessels, which are all the roads along which blood flows.

Question 3

What are the three types of blood vessels in the body?

Answer 3

• Arteries
• Veins
• Capillaries

Question 4

What do the arteries do?

Answer 4

Arteries carry blood from the heart, moving it under pressure with each heartbeat.

Question 5

How do arteries withstand the pressure from the beats of the heart?

Answer 5

Its walls are tough and elastic, bouncing back into shape after every beat.

Question 6

What happens if an artery is cut?

Answer 6

The high pressure within it causes blood to spurt out quickly, so all major arteries are protected deep in the body.

Question 7

What is the expansion and contraction of your arteries?

Answer 7

Your pulse.

Question 8

What are capillaries?

Answer 8

Small blood vessels that branch out from arteries, they reach nearly every cell of the body and are only one cell thick.

Question 9

What is good about the capillaries thin walls?

Answer 9

It allows dissolved materials to pass through them.

Question 10

What do capillaries do?

Answer 10

Cells absorb nutrients and release waste into capillaries, which the heart pumps to remove.

Question 11

What are veins?

Answer 11

Large blood vessels that are formed from capillaries.

Question 12

What do veins do?

Answer 12

Veins return blood to the heart; they have thin walls as pressure is lost in capillaries.

Question 13

How is blood pushed back up to the heart?

Answer 13

By the contraction of the muscles of your body pressing against the veins.

Question 14

What are valves?

Answer 14

Things along the length of the veins that make sure your blood flows in one direction.

Question 15

What do valves do?

Answer 15

Open when blood is flowing toward the heart and close when it is flowing away.

Question 16

What happens in your veins if you sit still for long periods of time?

Answer 16

The flow of the blood slows and pools, it may thicken and form a dangerous blood clot called a thrombosis.

Question 17

What happens when you bump yourself hard?

Answer 17

Some tiny capillaries near the skin burst and blood leaks out into the surrounding tissue, a red mark appears where the blood has leaked. (bruises)

Question 18

What happens as a bruise heals?

Answer 18

It fades to purple, then yellow as the blood is broken down and cleared away from the body.

Question 19

What size and where is your heart?

Answer 19

It is about the size of your fist and situated in the middle of your chest, behind the breastbone.

Question 20

What type of muscles is your heart made of and what does it do?

Answer 20

The cardiac muscle which does not get tired, it works continuously in response to the pacemaker.

Question 21

Why is the circulatory system referred to as the double system?

Answer 21

As there are two separate circuits which the blood flows, both of them start with the heart.

Question 22

How does the blood flow in one of the circuits of the system?

Answer 22

From the heart to the body and back to the heart. This circuit carries nutrients and oxygen to the cells and at the cells, collects waste.

Question 23

What needs to happen for the circulatory system to work?

Answer 23

The blood rich in oxygen (oxygenated) and blood with carbon dioxide (deoxygenated) must be kept separate where the two systems meet in the heart.

Question 24

How many chambers does your heart have and what do they do?

Answer 24

Four, two collect blood from the lungs and pump it round the body and the other two collect blood from the body and pump it to the lungs.

Question 25

Can you name all the different parts of the heart?

Answer 25

• Right atrium
• Right ventricle (pump chamber)
• Left atrium
• Left ventricle (pump chamber)
• Vena cava (main vein)
• Pulmonary artery (to lungs)
• Pulmonary vein (from lungs)
• Aorta (main artery)

Question 26

What are the three main phases of a heartbeat?

Answer 26

1. The two atria contract, pushing blood into the ventricles.
2. The ventricles contract, forcing blood out of the heart to the body and lungs.
3. The heart muscles relax and the atria fill with blood.

Question 27

What happens when the atria or ventricles contract?

Answer 27

Valves open or close to make sure blood flows in the right direction.

Question 28

What do coronary arteries do?

Answer 28

Supply the muscles of the heart with blood.

Question 29

What is the significance of the inner walls of the arteries?

Answer 29

Arteries are smooth for easy blood flow, but plaque buildup narrows them, reducing oxygen to the heart.

Question 30

What problems will a lack of oxygen to the heart cause?

Answer 30

A condition called ‘angina’, a person suffering from an angina attack experiences severe chest pain.

Question 31

What happens if arteries become completely blocked by plaque?

Answer 31

The part of the heart the arteries supply with oxygen dies and a heart attack occurs.

Question 32

What is plaque made up of?

Answer 32

Various substances that occur naturally in the blood, including calcium, cholesterol and fibrin.

Question 33

Blood…

Answer 33

…is the only organ in the body that is a liquid, the average adult has about 5L of blood.

Question 34

Why is blood important?

Answer 34

• Carries oxygen, nutrients and water to the cells and carbon dioxide and other wastes away
• It helps maintain your body temperature by spreading heat around your body.

Question 35

What are the four things in blood?

Answer 35

• Red blood cells
• White blood cells
• Platelets
• Plasma

Question 36

Where are red blood cells made?

Answer 36

Bone marrow in long bones such as the femur (thigh bone) and ribs. They contain a chemical called ‘haemoglobin’.

Question 37

What does haemoglobin do?

Answer 37

It is a pigment that gives red blood cells their red colour, they contain iron and carry oxygen around the body. There is 300 million in a drop of blood.

Question 38

What is the name of oxygen that is carried to cells?

Answer 38

Oxyhaemoglobin.

Question 39

What do white blood cells do?

Answer 39

They are bigger than red blood cells and 400,000 of them are in a drop of blood, they are part of the immune system that helps fight disease.

Question 40

What are platelets and what do they do?

Answer 40

Broken up bits of cells produced in the bone marrow, they help blood to clot.

Question 41

What happens if you have too little or too many platelets?

Answer 41

Too much can cause blood to clot in the blood vessels, but too little can cause you to bleed excessively.

Question 42

What will a blood clot in the blood vessels of the heart or brain do?

Answer 42

Heart: can cause angina or a heart attack.

Brain: can cause a stroke, where a part of the brain is starved of oxygen and dies.

Question 43

What is plasma?

Answer 43

A clear yellowish liquid that is 90% water and 10% dissolved materials such as nutrients and wastes. Red blood cells, white blood cells & platelets are all suspended in plasma.