Circulatory system and the Blood

Question 1

What main 4 components make up the blood?

Answer 1

Plasma, platelets, white blood cells, red blood cells

Question 2

What is a plasma?

Answer 2

A pale yellow liquid which carries things around the body.

Question 3

What does the plasma transport?

Answer 3

CO2
Urea
Hormones
Nutrients
Amino acids
Heat energy

Question 4

What are platelets?

Answer 4

Small fragments of cells that help blood clot.

Question 5

Explain the process of blood clotting.

Answer 5

They release chemicals when the blood is exposed to air, which cause soluble fibrinogen to be converted to insoluble fibrin. Fibrin forms a mesh, which traps platelets and red blood cells to form a clot.

Question 6

What are the types of white blood cells?

Answer 6

Phagocytes
Lymphocytes

Question 7

What is the function of red blood cells?

Answer 7

Transport oxygen around the body
Bind to haemoglobin

Question 8

How are red blood cells specialised for their job?

Answer 8

They contain haemoglobin which combines with oxygen to form oxyhaemoglobin which transports oxygen to respiring cells.
They have no nucleus so more haemoglobin can be packed into each cells so more oxygen can be transported.
Biconcave shape

Question 9

How does the biconcave shape help a red blood cell?

Answer 9

Increases their surface area: volume ratio and decreases the distance to the centre of the cell which increases the rate of diffusion.

Question 10

What are phagocytes?

Answer 10

Larger cells with a multi-lobed nucleus
Engulf and digest pathogens

Question 11

What are lymphocytes?

Answer 11

Cells with a very large nucleus
Make and release antibodies, which bind to and destroy pathogens.

Question 12

What is a pathogen?

Answer 12

A microorganism that can cause disease.

Question 13

How do phagocytes fight pathogens?

Answer 13

Phagocytes detect things that are foreign body. They then engulf the pathogens and digest them.
Phagocytes are non-specific - they attack anything that’s not meant to be there.

Question 14

How do lymphocytes fight pathogens?

Answer 14

When lymphocytes come across a foreign antigen they start to produce antibodies.
These lock on to the invading pathogens and mark them out for destruction by other white blood cells.
Antibodies are then produced rapidly and flow around the body to mark all similar pathogens.
Memory cells are also produced in response to a foreign antigen. They can reproduce very fast if the same antigen enters the body again.

Question 15

How do vaccinations protect from future infections?

Answer 15

Vaccinations involve injecting dead or inactive pathogens into the body. They are harmless but still have antigens so the body can produce antibodies to attack them.
Memory cells will be produced so if a similar pathogen enters the body again the body knows how to combat it.

Question 16

What are the three types of blood vessels?

Answer 16

Arteries
Capillaries
Veins

Question 17

What is the function of the artery?

Answer 17

Can transport blood at high pressure without bursting
Allows artery to stretch and recoil to keep blood flowing at high pressure.
Helps to control flow of blood by widening and narrowing.

Question 18

What is the function of capillaries?

Answer 18

Short diffusion distance of substance from blood into tissues

Question 19

What is the function of the vein?

Answer 19

Blood is flowing at lower pressure so thick wall not needed
Prevents blood flowing backwards.

Question 20

What is the structure of the artery?

Answer 20

Thick outer wall
Thick layer of elastic tissue
Thick layer of muscular tissue

Question 21

What is the structure of a vein?

Answer 21

Fairly thin outer wall
Thin layer of muscle and elastic tissue
Semilunar valves

Question 22

What is the structure of a capillary?

Answer 22

Wall is one cell thick

Question 23

The right atrium of the heart receives ________________ blood from the body through the _______ ______

Answer 23

deoxygenated
vena cava

Question 24

The deoxygenated blood from the right atrium moves through to…

Answer 24

the right ventricle which pumps it to the lungs via the pulmonary artery.

Question 25

The _____ atrium receives ____________ blood from the lungs through the _____________ _____.

Answer 25

left
oxygenated
pulmonary vein

Question 26

The oxygenated blood then moves through to the ______ ventricle which pumps it around the the body via the _______.

Answer 26

left
aorta

Question 27

Why is the left ventricle thicker than the right ventricle?

Answer 27

Because it needs more muscle to pump blood around the whole body whereas the right ventricle only has to pump it into the lungs.

Question 28

What do the valves in the heart do?

Answer 28

They prevent backflow

Question 29

How does exercise effect the heart rate?

Answer 29

When exercise starts the muscles produce more CO2 in aerobic respiration
Sensors in the aorta and carotid artery detect this increase
They send nerve impulses to the medulla
The medulla responds by nerve impulses along the accelerator nerve
The accelerator nerve increases the heart rate
More blood is supplied to the muscles to meet the demands of increased aerobic respiration

Question 30

What factors lead to CHD?

Answer 30

Smoking which makes it more likely fatty deposits will form.
A diet high in saturated fat
Not exercising enough which leads to high blood pressure.

Question 31

What is CHD?

Answer 31

This is when the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up.
This causes the arteries to become narrow, so blood flow is restricted and there’s a lack of oxygen to the heart muscle and then a heart attack.