Chapter 6: Transport in Humans

Question 1

What are the main components of blood?

Answer 1

Plasma
Red blood cells
White blood cells
Platelets

Question 2

Describe plasma.
(components+ function)

Answer 2

Components:
Mainly water, blood cells, excretory products (e.g. urea), substances (e.g. glucose, proteins etc.)

Function:
-Transports blood cells around the body,
-excretory products (e.g. urea) to excretory organs for removal
-nutrients from small intestines to other parts of the body

Question 3

Describe red blood cells.
(features+ function)

Answer 3

Features:
-Filled w/ haemoglobin->binds to oxygen
-Absence of nucleus->carry more haemoglobin to transport more oxygen
-Circular biconcave shape->increases surface area to volume ratio for faster uptake of oxygen
-Flexible->enables cells to squeeze through tiny blood capillaries

Function:
-Transport oxygen to cells in the body

Question 4

Describe white blood cells.
(features+ function)

Answer 4

Features:
-Colourless, no haemoglobin
-Irregular in shape, contains nucleus
-Mobile (move, change shape, squeeze thru tiniest capillaries)

Function:
-Protective function (defense)

Question 5

What are the 2 types of white blood cells?

Answer 5

Phagocyte
Lymphocyte

Question 6

What are the properties of phagocytes?
(+function)

Answer 6

-Lobed nucleus w/ granular cytoplasm

Function:
-Ingest, engulf and digest foreign particles (phagocytosis)

Question 7

What are the properties of lymphocytes?
(+function)

Answer 7

-Large, rounded nucleus w/ small amnt of non-granular cytoplasm

Function:
Produces antibodies to:
1. recognise and destroy pathogens
2. cause pathogens to clump tgt for easy ingestion (by phagocytes)
3. neutralise toxins produced by bacteria

Question 8

Describe platelets.
(features+function)

Answer 8

Features:
-Not true cells, membrane-bound fragments of cytoplasm

Function:
Helps in blood clotting

Question 9

Describe the process of blood clotting.

Answer 9

-Platelets contain thrombin, which helps convert soluble fibrinogen to insoluble fibrin threads
-Fibrin threads entangle the blood cells and form a clot (coagulation) to seal a wound

Question 10

What antigen and antibody does blood group A contain?

Answer 10

antigen: A
antibody: b

Question 11

What antigen and antibody does blood group B contain?

Answer 11

antigen: B
antibody: a

Question 12

What antigen and antibody does blood group AB contain?

Answer 12

antigen: A and B
antibody: -

Question 13

What antigen and antibody does blood group O contain?

Answer 13

antigen: -
antibody: a and b

Question 14

[Application]
What if type A blood is given to a person with type B blood?

Answer 14

-The antibody a in the plasma of the recipient will bind to the antigen A on the red blood cell of the donor’s blood.
-Agglutination of red blood cells will occur, blocking up small blood vessels and preventing the flow of blood.
-This leads to death.

During blood transfusion, consider effect of
Recipient’s plasma (antibodies) on
Donor’s RBC (antigens)

Question 15

What are the 3 types of blood vessels?

Answer 15

Arteries
Veins
Capillaries

Question 16

[Structure to Function]
How are arteries adapted to their function?

Answer 16

Function:
-Carry blood away from heart
-Transports oxygenated blood (except pulmonary artery) to other parts of the body

Structure:
-Thick, muscular walls-> withstand & prevent rupture during influx of blood at high pressure
-Elastic-> help artery wall to stretch and recoil
-Small lumen relative to diameter

Question 17

[Structure to Function]
How are veins adapted to their function?

Answer 17

Function:
-Carry blood towards heart
-Transports deoxygenated blood (except pulmonary vein) back to the heart

Structure:
-Thin walls with less elastic tissue-> blood is flowing to veins at low pressure
-Presence of valves-> blood pressure in veins is low, valves prevent backflow of blood
-Large lumen relative to diameter

Question 18

[Structure to Function]
How are capillaries adapted to their function?

Answer 18

Function:
-Allows exchange of materials between blood and tissue

Structure:
-Large capillary network (tiny and numerously branched)
->increases surface area to volume ratio for faster exchange of substances between blood and cells
->increases total cross-sectional area, lowering blood pressure and slowing the blood flow for more time for exchange of substances

-Endothelium consists of a single layer of flattened cells->shorten diffusion distance for faster exchange of substances between blood and cells

-Continuous blood flow->steep concentration gradient

Question 19

Describe the transfer of substances between capillaries and tissue cells.

Answer 19

-Useful materials and oxygen move from blood->capillaries->tissue fluid->cells (diffusion)

-Waste products released by cells->tissue fluid(diffusion)->capillary walls->blood->excretory organs for removal

Question 20

What are the two types of circulation involved in double circulation?

Answer 20

Pulmonary circulation
Systemic circulation

Question 21

Describe the path of pulmonary circulation.

Answer 21

From heart, pulmonary arteries carry deoxygenated blood to the lungs
Oxygenated blood is returned to the heart by pulmonary veins

Pulmonary circulation-> circulation between lungs and heart

Question 22

Describe the path of systemic circulation.

Answer 22

Oxygenated blood leaves heart to the rest of the body through arteries
Deoxygenated blood enters the heart through vena cava

Question 23

What is the difference between agglutination of blood and clotting of blood?

Answer 23

Agglutination is the clumping of red blood cells
Clotting of blood is the entangling of red blood cells in insoluble fibrin threads

Agglutination is caused by a reaction between antigen on red blood cells and antibody in plasma
Clotting of blood is caused by platelets causing the formation of insoluble fibrin threads