The Circulatory System

Question 1

What are the three main components that make up the circulatory system?

Answer 1

-The blood
-The blood vessels
-The heart

Question 2

What are the two functions of the circulatory system?

Answer 2

1. Transport substances around the body
2. Provides protection against disease

Question 3

What four components make up our blood?

Answer 3

-Red blood cells
-White blood cells
-Plasma
-Platelets

Question 4

What is the function of red blood cells?

Answer 4

Carry oxygen around the body.

Question 5

How are red blood cells adapted to their function/role of carrying oxygen around the blood?

Answer 5

-They contain the pigment haemoglobin (rich in IRON). This is the part of the cell that the oxygen molecules attach to.
-They are BICONCAVE in shape. This gives the cell a large surface area for diffusion. It also makes the cells thin, which reduces the diffusion pathway (oxygen can easily diffuse in).
-They have NO NUCLEUS. This means that more haemoglobin can be carried in each cell.

Question 6

What happens if red blood cells are placed in water? Why?

Answer 6

They will swell and eventually burst as water is taken into the cell by osmosis. This is because they have no cell walls and this process is known as CELL LYSIS.

Question 7

What part of the body closely controls the concentration of body fluids?

Answer 7

The kidneys.

Question 8

What is the function of the white blood cells?

Answer 8

To protect the body from the disease.

Question 9

What are the two types of white blood cells and what do they do?

Answer 9

1. Phagocytes: Engulf and digest micro-organisms (pathogen) in a process called PHAGOCYTOSIS.
2. Lymphocytes: Produce antibodies

Question 10

What is the function of platelets?

Answer 10

They are important in blood clotting.

Question 11

How do platelets work?

Answer 11

The convert soluble protein FIBRINOGEN into INsoluble FIBRIN which then forms a mesh-like structure. This mesh traps blood cells and forms a scab.

Question 12

Why is a scab formed?

Answer 12

-To prevent excess loss of blood
-To prevent entry of pathogens

Question 13

What is the function of the plasma? (BAWHA)

Answer 13

Transport man substances around the body such as:
1. Blood cells
2. Absorbed food molecules-glucose, amino acids
3. Waste products of metabolism-carbon dioxide and urea
4. Hormones
5. Antibodies

Question 14

Give 3 differences between red and white blood cells:

Answer 14

1. White blood cells have a nucleus (red don’t)
2. Red blood cells are biconcave in shape
3. There are two types of white blood cells
4. Red blood cells are heavier than