Circlulation

Question 1

Explain all the blood components-

Answer 1

WBC, RBC, platelets, plasma

WBC- contains a multi lobed nucleus. Part of the body’s defense system against microorganisms.
RBC- it is a biconcave disc shaped cell with no nucleus. RBC transports oxygen from the lungs to the organs. Contains a red pigment called as haemoglobin. Haemoglobin reacts with oxygen to produce oxyhemoglobin. In other organs oxyhemoglobin is split into oxygen and haemoglobin again.

Platelets- are small cell fragments with no nucleus. They help blood to clot at the site of a wound.

Plasma- liquid portion of the blood. Wbc, RBC, platelets are suspended in plasma. Plasma transports carbon dioxide from the organs to the lungs. Transports soluble substances from the small intestine to other organs.
Transports urea from the liver to the kidneys.

Question 2

How might more red blood cell
production help the marathon
runners?

Answer 2

More RBC means there will be more oxygen carrying capability, causing more oxygen to be delivered to muscles , so the rate of respiration in marathon runners would increase which increases the energy released.

Question 3

What are the three types of blood vessels-

Answer 3

Arteries- carry the blood away from the heart
Capillaries- involved with the exchange of material at the tissues
Veins- carry the blood to the heart

Question 4

Explain all the blood vessels functions-

Answer 4

Arteries- Are strong and elastic because they’re able to withstand high pressure from the blood pumping in the heart.
They have strong walls and arteries contain elastic fibres which allow them to stretch out and spring back.

Capillaries-
Are very tiny.
One cell thick (they’re thin) which produces a short diffusion pathway for oxygen and carbon dioxide.
They have permeable walls which allow substances to diffuse in and out.
They carry blood close to every cell in the body to exchange materials with them.

Veins-
Capillaries eventually join up to form veins.
Blood in the veins move at a lower pressure, so the veins walls do not have to be as thick as artery walls.
Veins have valves which allow blood to flow in one direction.

Question 5

How does blood clotting work?

Answer 5

Blood clotting refers to enzyme controlled reactions. Which results in a change from fibrogen to fibrins leading to a network of fibrins trapping in blood cells to form a clot.

Question 6

Explain the blood flow in the heart?

Answer 6

Deoxygenated blood enters the right atrium via the vena cava. The blood goes to the right ventricle. Right ventricle then pumps the blood out of the heart via the pulmonary artery, so that the blood can flow to the lungs to receive oxygen.

The oxygenated blood enters the left atrium via the pulmonary vein. The blood then flows to the left ventricle. Left ventricle pumps the blood out of the heart via the aorta, so that the blood can flow around the body.

Question 7

What is the function of a valve? 2 marker

Answer 7

Prevents the back flow of blood. Makes sure blood flows in one direction.

Question 8

What is coronary heart disease? And how is it caused? How will CHD have an effect on the coronary arteries?

Answer 8

CHD happens when layers of fatty material (plaque) to build up in the coronary arteries.
It is caused by the person being on a diet too high in saturated fat and cholesterol.
Due to CHD, the coronary arteries will narrow which leads to restricted blood flow.

Question 9

What will happen to the coronary arteries in partial blockage/ full blockage of plaque?

Answer 9

Partial blockage: restricted blood flow to the cardiac muscle cells which causes severe chest pain.
Full blockage: cells in that area of the coronary artery filled with fatty material will not be able to respire aerobically leading to a heart attack.

Question 10

How can CHD be treated?

Answer 10

By stents and statins.

Question 11

How is stents an effective strategy for treating CHD?

Answer 11

Stents are used to keep the coronary arteries open.
They’re high effective for reducing the risk of a heart disease because they widen the lumen to increase the blood flow to the coronary arteries.

Question 12

State the advantages and disadvantages of stents-

Answer 12

Advantages-
Simple procedure to insert a stent.
Dis- blood vessel can get damaged during surgery.

Adv-
Lasts a long time
Dis-
Risk of infection during surgery

Adv-
Effective in reducing the risk of a heart attack due being able to widen the lumen to increase blood flow.
Dis-
Can cause blood clots

Question 13

Describe how statins are also effective for fighting CHD-

Answer 13

Statins are drugs which are used to lower the level of cholesterol in the blood.

Statins block an enzyme in the liver which is needed to make cholesterol.
This slows down the buildup of cholesterol/ fatty materials in the blood reducing the risk of CHD

Question 14

State the advantages and disadvantages of statins-

Answer 14

Adv-
Statins reduce the levels of cholesterol/ fatty materials in the blood. Statins cause a small build up of cholesterol which reduces the risk of CHD.

Dis- these drugs need to be taken regularly or they will not be effective.

Adv-
Statins increase the levels of good cholesterol in the blood which decreases the levels of bad cholesterol.
Dis-
Side effects of statins include muscle and joint pain, kidney problems and neurological issues.

Question 15

How can the volume of blood pumping by the heart be reduced?

Answer 15

Because the valves can stiffen causing them not to open fully to allow boood to flow through.

Question 16

How can faulty heart valves be replaced?

Answer 16

by mechanical valves and biological valves from cows or pigs

Question 17

State eye advantages and disadvantages of mechanical valves and biological valves-

Answer 17

Mechanical valves-
Adv-
Long lasting, less need to replace
Dis- can cause blood clots. Need to take blood clotting medication throughout life hood.

Adv-
Highly effective. Less likely to leak.
Dis- need to be replaced after 12-15 years
Risk of immune rejection.

Question 18

State the advantages and disadvantages of artificial hearts-

Answer 18

Adv-
Shorter waiting times
Dis-
AH don’t work as well as real hearts

Adv-
Less chances that the patients immune system will reject it.
Dis-
Increased chance of blood clots which can lead to a stroke.

Question 19

Explain why a person with a leaking heart valve has
difficulty exercising-

Answer 19

The person has a faulty valve, it can cause backflow of blood which leads to less blood being pumped around the body, so there will be less oxygen delivered to the muscles and cells which causes less aerobic respiration, and less released in the body and so anaerobic respiration takes place causing a build up of lactic acid which causes muscle fatigue.

Question 20

Why can the blood group AB can receive blood from all blood types?

Answer 20

Because they have no antibodies, so they will not destroy any foreign antigen if it were to enter the body causing people with blood group AB to receive all blood types.

Question 21

How to prevent rejection of the transplanted organ?

Answer 21

The donor organ needs to be the same blood type as the patients/ receipent.
The recipient needs to be treated with immunosuppressant drugs so that their immune system does not destroy healthy cells and tissues.

Question 22

What blood group can give blood to all blood types? Why?

Answer 22

Group O because they have no antigens

Question 23

State the meaning of antigens and antibodies-

Answer 23

Antigens- red blood cells with special molecules on their cell membrane
Antibodies- made by WBC and they destroy all foreign antigens by attaching themselves to these antigens.