Blood & Circulation

Question 1

Why do multicellular organisms need a transport system?

Answer 1

To transport oxygen from the lungs to other parts of the body
To transport carbon dioxide from the body back to the lungs
To carry substances such as glucose and urea around the body
To distribute heat around the body

Question 2

What is blood made up of?

Answer 2

Red blood cells
White blood cells (phagocytes and lymphocytes)
Platelets
Plasma

Question 3

What is a double circulation system?

Answer 3

Two separate circuits - pulmonary and systematic

Blood passes through the heart twice

Question 4

Adaptations of red blood cells

Answer 4

Bi-concave disc (donut) shape to maximise surface area to carry oxygen
Contain haemoglobin - red protein that combines with oxygen
No nucleus so they can contain more haemoglobin
Contains iron

Question 5

What is a pathogen?

Answer 5

Disease-causing organism

Can be bacteria, virus, fungi or protoctist

Question 6

Characteristics of a lymphocyte

Answer 6

Large round nucleus

Clear cytoplasm

Question 7

Characteristics of a phagocyte

Answer 7

Lobed nucleus

Granular cytoplasm

Question 8

Antibody production

Answer 8

Lymphocytes produces antibodies which fit onto pathogen’s specific antigens
Antibodies cluster around pathogen and hold it still
Antibodies only fit onto specific antigen

Question 9

Phagocytosis

Answer 9

Pathogen (apoptotic cell) appears

Phagocyte engulfs pathogen

Question 10

How does vaccination work?

Answer 10

Vaccination contains small amount of pathogen
Lymphocytes make small amount of antibodies to attach onto antigen
Pathogen is killed by antibodies and engulfed by phagocyte
Lymphocytes produce memory cells
Memory cells recognise pathogen and can produce lots of antibodies quickly

Question 11

What are platelets

Answer 11

Very small fragments of blood cells

Question 12

How are clots formed?

Answer 12

Platelets contain fibrinogen which is converted to fibrin at the wound
Fibrous mesh is produced which traps platelets
Blocks the wound and forms a scab
Prevents loss of blood and prevents bacteria from entering the blood

Question 13

What is coronary heart disease?

Answer 13

When the coronary arteries (which supply blood to the heart) are narrowed due to a build up of fatty substances eg cholesterol (atherosclerosis).
Restricts blood flow
Can result in a (fatal) heart

Question 14

Characteristics of arteries:

Answer 14

Small lumen, thick elastic walls
Carry oxygenated blood away from heart in pulses
Lie further beneath surface of skin
Carry blood under high pressure

Question 15

Characteristics of veins:

Answer 15

Large lumen, thin walls
Carry deoxygenated blood to the heart
Have valves to prevent backflow
Lie further beneath surface of skin
Carry blood under low pressure

Question 16

Characteristics of capillaries:

Answer 16

Very small lumen, thin walls (only 1 cell thick)

Lie close to surface of the skin.

Question 17

What are factors increasing the risk of coronary heart disease?

Answer 17

Genetic/hereditary
Smoking (raises blood pressure)
Diet (large amounts of saturated fat)
Stress (raises blood pressure)
Lack of exercise