Blood

Question 1

What are the four main constituents of blood?

Answer 1

Red blood cells
White blood cells
Platelets
Plasma

Question 2

What is the function of red blood cells, and how are they adapted to this function?

Answer 2

Red blood cells carry oxygen from the lungs to the body cells.
They have a biconcave disc shape to increase surface area to absorb more oxygen.
They do not contain a nucleus so that there is more room to carry oxygen.
They contain the red pigment haemoglobin, which binds to oxygen to become oxyheamoglobin.

Question 3

What is the function of white blood cells?

Answer 3

White blood cells are part of the immune system ; defending against infection.
They can perform phagocytosis by engulfing and digesting pathogens.
They produce antitoxins to neutralise the toxins produced by microorganisms.
They produce antibodies that help to destroy harmful microorganisms.

Question 4

What is the function of platelets?

Answer 4

Platelets help to clot blood.
They are small fragments of cells, with no nucleus.
They prevent excess blood loss and also prevent harmful pathogens from entering the wound and causing infection.

Question 5

What is the plasma?

Answer 5

Plasma is a pale, straw-coloured liquid that carries the components of blood.
This includes :
Red blood cells, white blood cells and platelets.
Nutrients - glucose, amino acids.
Waste products - CO2, urea.
Hormones
Proteins
Antibodies and Antitoxins.