Blood And Circulation

Question 1

Function of plasma

Answer 1

To carry blood cells around the body and distribute heat around the body

Question 2

What’s in the plasma

Answer 2

1. Dissolved nutrients
2. Hormones
3. Carbon dioxide
4. Urea

Question 3

Function of red blood cells

Answer 3

To carry oxygen

Question 4

How do structures of red blood cells work to their advantage

Answer 4

1. No nucleus: more haemoglobin can be transported
2. Biconcave shape: allows efficient exchange of oxygen in and out of cells
3. Thin cell surface membranes: gives it short diffusion

Question 5

How do phagocytes work

Answer 5

1. They change their shape to produce extensions (pseudopodia)
2. The pseudopodia encloses microorganism in a vacuole
3. Digestive enzymes break down microorganism

Question 6

How do lymphocytes work?

Answer 6

1. Make chemicals called antibodies
2. Antibodies attach onto the antigens on pathogens
3. Destroy bacteria by; causing bacteria to stick together so that a phagocyte can ingest it, acting as a label for a phagocyte, causing bacteria to burst open, neutralising poisons that pathogens can have

Question 7

Function of platelets

Answer 7

1. If the skin is cut fibrin is made
2. Traps the red blood cells around the wound
3. This forms a clot which prevents further loss of blood and entry of pathogens

Question 8

Describe how the heart beats

Answer 8

1. Blood enters the atria
2. When the atria contracts the bicuspid and tricuspid valves are forced open allowing the blood to flow into the ventricles
3. When the ventricles are full they contract- increases pressure of blood closing the bicuspid and tricuspid valves
4. The pressure continues to increase and forces open the semi lunar valves and the blood leaves the heart

Question 9

What part does oxygenated blood enter and leave the heart

Answer 9

Enters: pulmonary vein
Exits: pulmonary artery

Question 10

What part does deoxygenated blood enter and leave the heart

Answer 10

Enters: vena cava
Exits: aorta

Question 11

Where does the pulmonary artery and aorta carry blood to

Answer 11

Pulmonary artery: lungs

Aorta: other parts of body

Question 12

Arteries function and structure

Answer 12

Function: to carry blood away from the heart
Structure: thick, muscular, elastic walls- stops walls breaking when heart beats; small lumen

Question 13

Veins structure and function

Answer 13

Function: to carry blood into the heart
Structure: thinner muscular walls, small lumen, valves- to prevent back flow

Question 14

Function and structure of capillaries

Answer 14

Function: takes blood to and from respiring tissues
Structure:thin permeable walls, one cell thick

Question 15

Difference between a single and a double circulatory system

Answer 15

Single: blood is pumped from heart to the gas exchanged organ and then directly to the rest of the body
Double: same as single except it goes back to the heart and then to the rest of the body

Question 16

What’s the composition of the blood

Answer 16

1. Red blood cells
2. White blood cells (lymphocytes and phagocytes)
3. Platelets
4. Plasma