Transport In Humans

Question 1

What is blood composed of?

Answer 1

Plasma - water , proteins mineral salts, food substances and waste products , platelets , red blood cells, white blood cells

Question 2

What are platelets and what is its function?

Answer 2

Membrane-bound fragments of cytoplasm to help in blood clotting

Question 3

How is the red blood cell adapted for its function?

Answer 3

Adaptation: filled with red pigment haemoglobin
Function: binds with oxygen to form oxyhaemoglobin
Adaptation: circular biconcave shape
Function: increases surface area to volume ratio for faster uptake of oxygen
Adaptation: elastic
Function: cells can squeeze through tiny blood capillaries

Question 4

What are the functions of phagocytes

Answer 4

Engulf and ingests foreign particles such as bacteria (phagocytosis)

Question 5

What is the function of lymphocytes

Answer 5

Produces antibodies that can act as antitoxins, causes agglutination or kills bacteria directly

Question 6

what are the causes of coronary heart disease?

Answer 6

smoking, a sedentary lifestyle, emotional stress and a high-fat diet rich in cholesterol and saturated animal fats

Question 7

how do you prevent coronary heart disease?

Answer 7

a healthy diet with reduced intake of animal fats which can be replaced with polyunsaturated plant fats and rich in vegetables and fruits, management of stress in an appropriate way, regular exercise and avoidance of smoking

Question 8

what is coronary heart disease?

Answer 8

the build up of fatty substances on the inner walls of the coronary arteries causing the lumen of the arteries to narrow , reducing blood flow to the heart. The heart muscle cells receive reduced oxygen supply and this may lead to a heart attack

Question 9

how are blood types named

Answer 9

Through the antigen present on the red blood cell ( A, B, no antigen or both )

Question 10

what is considered during a blood transfusion?

Answer 10

the effect of the recipients plasma on the donors red blood cell

Question 11

what are the functions of blood?

Answer 11

Acts as a transport medium for carrying various substances from one part of the body to the other ( excretory products, digested food substances)
- Protects the body against disease-causing organisms (wbc and platelets)
- prevents excessive blood loss by blood clotting or agglutination at wounds

Question 12

How is oxygen transported to the body cells

Answer 12

as blood passes through the lungs ,oxygen diffuses from the air sacs into the lungs into the blood. Haemoglobin in the blood combines with oxygen to form oxyhaemoglobin. Blood transports oxygen to all tissues in the body and the oxyhaemoglobin releases oxygen to the body cells at the tissue cells

Question 13

how does clotting occur\ what happens after one cuts themselves

Answer 13

The damaged tissues and platelets produce thrombokinase which converts inactive prothrombin to active thrombin in the presence of calcium ions. the thrombin then converts soluble fibrinogen to insoluble fibrin threads that entangle blood cells and forms a clot

Question 14

how to reduce the risk of tissue rejection?

Answer 14

ensure there is a tissue match \ use immunosuppressive drugs

Question 15

production and function of antibodies

Answer 15

produced by lymphocytes.
Antibodies act by destroying the bacteria ; attaching to them, causing the bacterial surface membrane to rupture
Causing the bacteria to clump together / agglutinate so that they can be easily ingested by the phagocytes
Neutralising the harmful substances (toxins) produced by bacteria
antibodies bind to bacteria and cause their surface membranes to rupture. bacterial cells clump together in the presence of antibodies and the toxins produced are neutralised by antibodies

Question 16

What is the function of arteries?

Answer 16

transports oxygenated blood away from the heart to the rest of the body

Question 17

characteristics and adaptations of arteries

Answer 17

Small lumen, thick muscular walls to prevent rupture during influx of oxygenated blood at high pressures.

Question 18

What is the function of veins?

Answer 18

transports deoxygenated blood back to the heart

Question 19

characteristics and adaptations of veins

Answer 19

thin walls with less elastic tissue as blood flowing in veins is lower. Valves to prevent backflow of blood.

Question 20

function of capillaries

Answer 20

allows for the exchange of materials between blood and tissue

Question 21

characteristics and function of capillaries?

Answer 21

large capillary network to increase surface area to volume ratio for faster exchange of substances between blood and cells

endothelium is one cell thick to allow permeability to H2O and other substances and increase the rate of diffusion

Question 22

how is waste products removed from the cell?

Answer 22

waste products released by cells -> tissue fluid through diffusion -> capillary walls -> blood -> excretory organs for removal

Question 23

what are the advantages of double circulation

Answer 23

blood enters the pulmonary circulation at a low pressure, ensuring sufficient time for blood to be fully oxygenated before returning to the heart

The heart pumps oxygenated blood at high pressure to the rest of the body so oxygenated blood is distributed to the body tissues more quickly, helping maintain high metabolic rate in mammals

Question 24

what is pulmonary circulation?

Answer 24

blood circulation linking the heart to the lungs

Question 25

what is systemic circulation?

Answer 25

circulation of blood linking the heart to he rest of the body , except the lungs

Question 26

what is the pathway of the blood through the body?

Answer 26

Deoxygenated blood returns to the heart via the vena cava
the right atrium contracts and blood is forced to enter the right ventricle.
the right ventricle contracts and blood leaves through the pulmonary artery
blood leaves the heart and enters the lungs via the pulmonary artery. oxygenated blood is forced to the left atrium via the pulmonary veins.
The left ventricle contracts and blood is forced towards the aorta.
blood leaves the heart via the aorta and is pumped to the rest of the body.

Question 27

which artery transports oxygenated blood to the kidney?

Answer 27

renal artery

Question 28

which artery transports oxygenated blood to the liver?

Answer 28

hepatic artery

Question 29

What is phagocytosis?

Answer 29

The process of engulfing / ingesting foreign particles like bacteria by the white blood cells

Question 30

How can you prevent tissue rejection?

Answer 30

Ensure that there is a tissue match - > the tissues of both the donor and recipient must be as genetically close as possible.

Use immunosuppressive drugs that inhibits responses of the recipients immune system. Although this could lead to problems like
Lowering the resistance of the recipient to many kinds of infection
The recipient has to continue takin drugs for the rest of their life

Question 31

What are the advantages of red blood cells changing their shape as they flow through narrow blood capillaries?

Answer 31

The diameter of the RBCs are reduced so it can easily pass through the lumen of the capillaries
The cell increases its surface area to speed up absorption / release of oxygen
The rate of blood flow is reduced thus giving more time for , thus increasing the efficiency of exchange of materials between the blood and the tissue cells

Question 32

Why are the ventricles thicker than that of the atria?

Answer 32

The atria only forces blood into the ventricles and thus does not require high pressure while the ventricles have comparatively thicker muscular walls ( especially the left ventricle) as it has to pump blood around the whole body