Circulatory system

Question 1

What does the blood contain?

Answer 1

Red blood cells, White blood cells, platelets, and plasma

Question 2

What is the red blood cell?

Answer 2

It is a disc-shaped cell lacking a nucleus, which carried oxygen.

Question 3

What is the white blood cell?

Answer 3

It is an irregular shaped cell with a nucleus, which is involved in immunity.

Question 4

What are platelets?

Answer 4

They are cell fragment involved in blood clotting. This prevents blood loss and the blood clot prevents the entry of microorganisms into the cut or wound.

Question 5

What is the plasma?

Answer 5

it is the liquid watery part that carried CO2, glucose and hormones.

Question 6

What is the role of blood plasma?

Answer 6

The watery plasma is used to transport soluble substances from one part of the body to another.

Question 7

Role of blood plasma in carbon dioxide:

Answer 7

Carbon dioxide is transported from respiring cells in the lungs, from where it is excreted from the body.

Question 8

Role of blood plasma in Digested food:

Answer 8

Digested food is transported form the small intestine, where it is absorbed to all the cells in the body.

Question 9

Role of blood plasma in Urea:

Answer 9

Urea from there liver cells are transported to the kidneys, from where it is exerted in the urine.

Question 10

Role of blood plasma in hormones:

Answer 10

Hormones are transported from the glands that secrete them to other parts of the body where they control processes.

Question 11

Role of blood plasma in heat energy:

Answer 11

Heat energy from organs where it is produced eg. the liver and contracting muscles, to the rest of the body.

Question 12

Adaptations of Red blood cells:

Answer 12

• Large surface area due to biconcave disc shape.
• Contain haemoglobin to bind to oxygen.
• No nucleus so more space for haemoglobin.
• Flexible and small size so can pass along narrow capillaries.

Question 13

What cause disease? Give examples:

Answer 13

Pathogens
- bacteria
- fungi
- viruses

Question 14

What response does the immune system have when pathogens invade the body.

Answer 14

When pathogens invade the body, the immune system, response by producing more white blood cells.

Question 15

What are the 2 types of white blood cells that destroy pathogens.

Answer 15

Phagocytes and lymphocytes

Question 16

What is a phagocyte?

Answer 16

These are irregular shaped white blood cells which ingest pathogens and destroy them by digesting them.

Question 17

What is a lymphocyte?

Answer 17

These are round white blood cells that release antibodies. Antibodies are protein molecules that are a specific shape and bind to a particular pathogen and then destroy it.

Question 18

What is a vaccination?

Answer 18

An injection of a killed or weakened pathogen is given as a vaccination.

Question 19

What do vaccinations do?

Answer 19

They stimulate the immune system to produce memory cells, which can recognise, the same pathogens in the future. This means that antibody production by lymphocytes is faster and in greater quantities. The pathogen is destroyed so quickly hat the person does not suffer any disease symptoms.

Question 20

How is blood pumped?

Answer 20

Blood is pumped by the heart into the arteries, then into capillaries and then into veins, which carry blood back into the heart.

Question 21

what is the function of an artery?

Answer 21

Arteries carry blood at a high pressure and help to maintain this high pressure so blood flow is rapid.

Question 22

what is the function of a vein?

Answer 22

Veins carry blood at a low pressure back to the heart mainly against gravity.

Question 23

what is the function of capillaries?

Answer 23

Capillaries allow exchange of materials between blood and the body cells.

Question 24

What is the structure of an artery?

Answer 24

1) Thick muscular wall to resist bursting at high pressure.
2) Small lumen (passageway of blood flow), so the high pressure can be maintained.
3)Elastic walls to allow expansion when the ventricles contract and recoil when the ventricles relax.

Question 25

What is the structure of a vein?

Answer 25

1) Thinner muscular wall as the blood pressure is low.
2) Large lumen so there is less resistance to blood flow.
3) Valves to prevent back flow of blood due to gravity.

Question 26

What is the structure of a capillary?

Answer 26

1) Very thin, permeable walls made of a single layer of cells, allowing soluble materials to diffuse through them.
2) Very small size so they can penetrate tissues and organs and supply all cells.