3.2 Circulatory System

Question 1

What organ moves blood around the body?

Answer 1

The heart (made from muscle tissue)

Question 2

Describe the journey of blood through a heart to the lungs?

Answer 2

Deoxygenated blood enters the right atrium through the vena cava
The right atrium contracts and blood is forced into the right ventricle through atrioventricular valves
The right ventricle contracts and the blood is pumper into the pulmonary artery
The pulmonary artery transports the blood to the lungs where CO2 diffuses out into the lungs and oxygen diffuses into red blood cells and binds to haemoglobin

Question 3

Describe the journey of blood through the heart from the lungs?

Answer 3

The blood now oxygenated at a lower pressure returns to the heart via the pulmonary vein and enters the left atrium
The left atrium contracts and the blood is forced into the left ventricle through the atrioventricular valves
The left ventricle contracts and the blood is forced under high pressure into the aorta and transported around the rest of the body

Question 4

Why are valves in the heart?

Answer 4

To prevent the back flow of blood

Question 5

What are heart strings used for in the heart?

Answer 5

They keep the valves in place

Question 6

Why is the septum in the heart?

Answer 6

It separates the oxygenated and deoxygenated blood

Question 7

What are coronary arteries and used for?

Answer 7

They lie on the surface of the heart and the heart immediately needs oxygenated blood to respire for energy to contract

Question 8

Why does the left ventricle have a thicker muscular heart wall?

Answer 8

It has to contract stronger to pump blood around the entire body

Question 9

What are the two separate circulatory systems?

Answer 9

One for the lungs and one for the rest of the organs

Question 10

What do arteries do?

Answer 10

Carries oxygenated blood away from the heart and to the organs (except the pulmonary artery)

Question 11

Name some properties of an artery?

Answer 11

Carries blood with high pressure
Thick layer of muscular and elastic tissue to with stand high blood pressure
Not permeable
Doesn’t contain valves

Question 12

What do veins do?

Answer 12

Carries deoxygenated blood from the organs back to the heart (except the pulmonary vein)

Question 13

Name some properties of a vein?

Answer 13

Carries blood with low pressure
Little muscular and elastic tissue (thinner walls)
Contains valves to prevent back flow of blood

Question 14

What do capillaries do?

Answer 14

Carry blood through organs allowing exchange of substances with all living cells

Question 15

Name some properties of capillaries?

Answer 15

Only 1 cell thick - short diffusion distance
Large network of them - large surface area
Only one red blood cell can fit through at one time

Question 16

Why is a stent used?

Answer 16

If arteries begin to narrow or are blocked blood flow is restricted so organ can become deprived of nutrients and oxygen

Question 17

What are stents used for?

Answer 17

To keep blood vessels open

Question 18

What are stents often used in and why?

Answer 18

Coronary arteries

They narrow due to fatty deposits cutting off blood to the heart

Question 19

What is the surgery called to insert a stent?

Answer 19

Angioplasty

Question 20

What is a stent made out of?

Answer 20

Metal mesh and it’s non-corrosive

Question 21

What are two differences between a foetal heart and an adult heart?

Answer 21

The foetal heart has:
The ductus venosus: connecting the pulmonary artery and the aorta
A hole between atriums

Question 22

How does the foetal heart change when born?

Answer 22

The ductus venosus closes upon the first breath as a result of increase in pressure and never reopens

The hole closes as a result of adrenaline causing high blood pressure when you are born

Question 23

Why is it important a foetal heart changes?

Answer 23

Oxygenated blood and deoxygenated blood need to be separated

It could cause fatigue if not enough oxygen gets to the muscles

Question 24

What is blood?

Answer 24

A tissue

Question 25

What does blood consist of?

Answer 25

Fluid called plasma
Red blood cells
White blood cells
Platelets

Question 26

What is the function of plasma?

Answer 26

It transports many substances:
CO2 from organs to lungs
Soluble products of digestion from small intestine to other organs (glucose and amino acids)
Urea from liver to kidney

Question 27

Name some properties of a red blood cell?

Answer 27

It is a biconcave disk (larger surface area)
No nucleus
Contains red pigment haemoglobin

Question 28

What is the function of a red blood cell?

Answer 28

The haemoglobin combined with the oxygen to form oxyhemoglobin in the lungs

Red blood cells transport this to the organs where the oxyhemoglobin can split back into the two components

Question 29

What is the reaction in red blood cells?

Answer 29

Oxygen + haemoglobin ⇌ oxyhemoglobin

Question 30

Describe a white blood cell and what it does?

Answer 30

Contains a nucleus
Part of the bodies defence system against pathogenic microorganisms
They engulf pathogens or produce antibodies and antitoxins

Question 31

What are platelets and what do they do?

Answer 31

Small fragments of cells
Don’t have a nucleus
They help clot blood at the site of a wound

Question 32

What does artificial blood not contain that blood from donors contain?

Answer 32

It doesn’t contain cells

Question 33

What are the advantages of artificial blood?

Answer 33

Doesn’t need refrigerating

Matching blood isn’t necessary

Question 34

What are the disadvantages of artificial blood?

Answer 34

Expensive
Doesn’t carry as much oxygen
Can be insoluble so doesn’t mix well with blood
Unpleasant side effects

Question 35

What are the advantages of an artificial heart?

Answer 35

It doesn’t need to match the persons tissue

No immunosuppressant drugs

Question 36

What are the disadvantages of an artificial heart?

Answer 36

Expensive
Can only be used for a short time
Issues with blood clotting
You have to spend a lot of time in hospital