Transport In Humans

Question 1

What does blood consist of?

Answer 1

Red blood cells.
White blood cells.
Platelets.
Plasma.

Question 2

What is the structure of red blood cells?

Answer 2

Biconcave disc without a nucleus.

Question 3

What is the structure of white blood cells?

Answer 3

Large cells with a big nucleus.

Question 4

What is the structure of platelets?

Answer 4

Fragments of cells.

Question 5

What is the structure of plasma?

Answer 5

Straw coloured liquid.

Question 6

What is plasma important for in transport?

Answer 6

CO2 – transported from respiring cells to lungs.
Digested food and mineral ions - to requiring cells.
Urea – transported to kidneys.
Hormones – released from endocrine gland and delivered to target organs.
Heat energy.

Question 7

What adaptations of red blood cells make them suitable for transporting oxygen?

Answer 7

Haemoglobin – binds to oxygen - Oxyhaemoglobin
No nucleus – more space for haemoglobin.
Biconcave disc - large SA:VOL ratio to maximise diffusion of oxygen.

Question 8

What are the two types of white blood cell?

Answer 8

Phagocytes
Lymphocytes

Question 9

Describe the process of phagocytosis?

Answer 9

When phagocytes encounter the pathogenic cell, they will engulf it and release digestive enzymes to digest and destroy it.
This is a non-specific immune response.

Question 10

What are antibodies produced by?

Answer 10

Lymphocytes

Question 11

What are antibodies?

Answer 11

Y-shaped proteins with a shape that is specific to the antigens on the surface of the pathogen.
This is a specific type of immune response – antibodies produced only fit 1 type of antigen on a pathogen.

Question 12

How do antibodies function?

Answer 12

Antibodies attached to specific antigens on the pathogen – causing agglutination (clumping).
Pathogenic cells can’t move easily.
Chemicals are released that signal to phagocytes to destroy these.

Question 13

How do lymphocytes neutralise toxins?

Answer 13

Lymphocytes produce antitoxins.

Question 14

When does an organism have immunity from a disease?

Answer 14

When it has a sufficient level of antibodies to protect it.

Question 15

What is the immune response?

Answer 15

Pathogen enters bloodstream and multiplies.
A release of toxins and infection of body cells causes symptoms.
Phagocytes encounter pathogen & engulf/digest them in phagocytosis.
The pathogen encounters lymphocytes, which recognises its antigens.
The lymphocyte produces specific antibodies to combat that pathogen.
The lymphocyte clones itself to produce lots of lymphocytes.
Antibodies cause agglutination – phagocytes engulf and digest, the agglutinated pathogens.
After recovery, specific antibodies are retained as well as memory cells.
The same pathogen being encountered again, triggers a secondary immune response.

Question 16

What do memory cells do?

Answer 16

Memory cells produce larger quantities of the required antibody in a shorter time to fight off the pathogen - before the patient experiences any symptoms.

Question 17

What is an anti-toxin?

Answer 17

A protein that neutralises the toxins produced by bacteria.

Question 18

How do vaccines work?

Answer 18

A dead form of the pathogen is injected into the blood.
Lymphocytes recognise the antigens in the bloodstream.
Activated lymphocytes produce antibodies specific to the antigen.
Memory cells and antibodies remain circulating in the bloodstream - future antibody production to pathogen happens sooner / faster / greater quantity

Question 19

Describe how platelets are involved in blood clotting?

Answer 19

When the skin is broken – platelets arrive to stop the bleeding.
Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh around the wound – trapping red blood cells.
Clot dries and develops into a scab.

Question 20

Describe the pathway of blood through the heart?

Answer 20

Deoxygenated blood from the body flows through the vena cava into the right atrium.
Atrium contracts and the blood is forced through the tricuspid valves into the right ventricle.
The ventricle contracts and the blood is pushed through the semilunar valve into the pulmonary artery.
The blood travels to the lungs and moves through the capillaries past the alveoli where gas exchange takes place.
Oxygenated blood returns via the pulmonary vein to the left atrium.
The atrium contracts and forces the blood through the bicuspid valves into the left ventricle & the ventricle contracts.
The blood is forced through the semilunar valve and out through the aorta.

Question 21

What is the function of valves?

Answer 21

Valves prevent the backflow of blood.

Question 22

What is the function of the coronary arteries?

Answer 22

Coronary arteries supply the cardiac muscle tissue of the heart with oxygenated blood.
Because the heart needs a constant supply of oxygen for aerobic respiration to release energy to allow contraction of muscles.

Question 23

Why does the left ventricle have a thicker muscle wall?

Answer 23

So it can pump blood at a high enough pressure around the entire body.

Question 24

Explain how the heart rate changes under exercise?

Answer 24

During exercise, muscle cells respire more rapidly to provide energy for muscle contraction.
More respiration means more requirement for oxygen and glucose & an increase in production of waste products that need to be removed.
Heart rate increases to deliver oxygen/glucose and remove waste more frequently.
The volume of blood pumped out of the heart also increases to deliver bigger quantities of oxygen and glucose

Question 25

What is the effect of adrenaline on heart rate?

Answer 25

More adrenaline means a higher heart rate.

Question 26

Describe how oxygen debt is paid off?

Answer 26

Heart rate may remain higher after exercise, as oxygen is required in the muscles to breakdown lactic acid from anaerobic respiration.

Question 27

What happens in coronary heart disease?

Answer 27

Layers of fatty material (plaque) buildup inside the coronary arteries.
These fatty deposits are mainly formed from cholesterol.

Question 28

What are the two sources of cholesterol in the body?

Answer 28

Dietary cholesterol.
Cholesterol made by the liver.

Question 29

What happens if a coronary artery becomes blocked by fatty deposits?

Answer 29

The coronary artery loses elasticity and can’t stretch enough to accommodate blood being forced through.
Less blood flow through the arteries means there is less oxygen for the heart muscle.

Question 30

What happens in a partial blockage of the coronary arteries?

Answer 30

Restricted blood flow to the cardiac muscle cells – angina

Question 31

What happens in a complete blockage of the coronary arteries?

Answer 31

Cells in that area of the heart won’t be able to respire aerobically – heart attack.

Question 32

How can you treat coronary heart disease?

Answer 32

Increase the width of the lumen of the coronary arteries – stent.
Statins to lower blood cholesterol.

Question 33

What are risk factors of CHD?

Answer 33

Obesity – extra strain on the heart.
High blood pressure – greater force of blood against artery wall – damages vessels.
Higher cholesterol – speeds up buildup of fatty plaques in arteries.
Smoking – Chemicals in smoke cause increase in plaque buildup and blood pressure.

Question 34

What are the three types of blood vessel?

Answer 34

Arteries.
Veins.
Capillaries.

Question 35

Describe the features of the arteries?

Answer 35

Carry blood at a high-pressure away from the heart.
Thick muscular walls with elastic fibres & narrow lumen.
Blood flows fast.

Question 36

How are arteries adapted?

Answer 36

Thick muscular walls with elastic fibres withstand high-pressure of blood and maintain the blood pressure.
Narrow lumen also helps maintain high-pressure.

Question 37

What are the features of veins?

Answer 37

Carry blood at a low pressure to the heart.
Thin walls and large lumen.
Have valves.
Blood flows slowly.

Question 38

How are veins adapted?

Answer 38

Large lumen reduces resistance to blood flow under low pressure.
Veins prevent backflow of blood.

Question 39

What are features of the capillaries?

Answer 39

Carry blood at low pressure within tissues.
One cell thick walls and leaky.
Slow blood flow.

Question 40

How are capillaries adapted?

Answer 40

One cell thick walls (short diffusion distance) so substances can easily diffuse in and out.
Leaky walls allow blood plasma to leak out and form tissue fluid surrounding cells.