B4 - (Part 1) Organising Animals

Question 1

What are the components of blood?

Answer 1

Platelets, plasma, red blood cells and white blood cells

Question 2

How to differentiate between the different types of wbc under a microscope

Answer 2

Phagocytes have a lumpy nucleus
Lymphocytes have a very large nucleus

Question 3

What is plasma and what is its function

Answer 3

• It is the liquid part of the blood
• Its function is to carry the blood cells, CO₂, nutrients, urea

Question 4

Structure and adaptations of a red blood cell

Answer 4

• No nucleus to carry more haemoglobin + O₂
• Biconcave so large SA:V so quick O₂ diffusion
• Small to squeeze through capillaries

Question 5

Function of red blood cells

Answer 5

• Carry oxygen due to haemoglobin which has iron which bind to O₂

Question 6

Function of phagocytes and lymphocytes

Answer 6

• Phagocytes - Engulf pathogens through phagocytosis
• Lympocytes - produces antibodies which target pathogens

Question 7

Structure and function of platelets

Answer 7

• Structure - small fragments of cells without a nucleus
• Function - help the blood to clot to stop blood loss

Question 8

Structure of arteries and why

Answer 8

• Thick, strong outer wall and thick layer of fibres and muscle as blood is under high pressure
• Small lumen (gap) to maintain high pressure

Question 9

Structure of veins and why

Answer 9

• Thin outer wall and thin layer of fibres and muscle to be squeezed by skeletal muscles
• Large lumen as blood is under low pressure

Question 10

Function of valves and where they are found

Answer 10

• Valves stop the backflow of blood
• They are only found in the veins

Question 11

Structure of capillaries and why

Answer 11

• Small lumen and wall made of a single layer of cells
• This allows there to be lots of capillaries
• It also allows substances to easily diffuse in and out of them

Question 12

Explain the different parts of the double circulatory system

Answer 12

• The pulmonary system carries low pressure blood to and from the lungs
• The systemic system carries high pressure blood to and from the body

Question 13

What causes the heart to pump blood?

Answer 13

• The pacemaker in the right atrium sends an electrical impulse atria and the ventricles which contract

Question 14

How does the heart recieve its own blood supply?

Answer 14

Through the coronary artery, located on the surface of the heart which supplies oxygen and glucose and removes CO₂

Question 15

What is coronary heart disease and how is it dangerous?

Answer 15

• Where the coronary artery gets clogged up with fatty deposit
• This reduces blood flow, O₂ supply to heart leading to less respiration, less heart muscle contraction

Question 16

Ways to fix or prevent coronary heart disease

Answer 16

• Stents - mesh that keeps artery open
• Statins - drugs to lower cholestrol
• Bypass surgery

Question 17

Complications with stents

Answer 17

• Wire mesh could be sharp + cut blood vessels
• Risk of infection
• Metal so could cause blood clots

Question 18

What are artificial pacemakers used for

Answer 18

To correct irregularities in the heart rate if the pacemaker isn’t working

Question 19

Consequences of faulty valves

Answer 19

• Breathless as not enough oxygenated blood going round
• Can be fatal

Question 20

Different types of valve replacements

Answer 20

• Biological valves
• Mechanical valves

Question 21

Advantage and disadvantage of mechincal valve replacements

Answer 21

• Last a lifetime
• Need to take anticoagulants

Question 22

Advantages and disadvantages of biological valve replacements

Answer 22

• No need to take anticoagulants
• Don’t last for long
• Religious concerns

Question 23

What is an artificial heart and its advantages

Answer 23

• A mechanical heart given whilst waiting for a permanent transplant
• Gives the heart a rest and time to recover

Question 24

Disadvantages of artificial hearts

Answer 24

• Metal so risk of blood clotting
• Very costly
• Not a permanent replacement

Question 25

Adaptions of the alveoli (3)

Answer 25

• Large surface area for more diffusion
• Good blood supply to manitain conc. gradient
• Thin walls for short diffusion distance

Question 26

What happens in the gas exchange system when you breathe in

Answer 26

• Intercostal muscles contract moving ribs up and out
• Diaphragm contracts and moves down
• Pressure decreases inside chest so air rushes in

Question 27

What happens in the gas exchange system when you breathe out

Answer 27

• Intercostal muscles relax moving ribs down and in
• Diaphragm relaxes and moves up
• Pressure increases inside chest so air rushes out