Circulatory System - Blood

Question 1

What is the job of red blood cells?

Answer 1

To carry oxygen from the lungs to all the cells in the body.

Question 2

How are red blood cells adapted to their job?

Answer 2

1. Their shape is a biconcave disc which gives a large surface area for absorbing oxygen. 2. No nucleus so more room to carry oxygen.

Question 3

What is the name of the red pigment red blood cells contain? What do they do?

Answer 3

Haemoglobin. In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin. In body tissues, the reverse happens - oxyhaemoglobin splits up into haemoglobin and oxygen, to release oxygen to the cells.

Question 4

How do white blood cells defend against infection?

Answer 4

1. Some change shape to defend against unwanted microorganisms, in a process called phagocytosis.
2. Others produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins produced by the microorganisms.

Question 5

Do white blood cells have a nucleus?

Answer 5

Yes, unlike red blood cells.

Question 6

What are platelets? How do they help blood clot?

Answer 6

They are small fragments of cells (have no nucleus).

Help blood to clot at a wound to stop all your blood pouring out and stoop microorganisms getting in.

Question 7

Why do you need platelets?

Answer 7

Lack of platelets can cause excessive bleeding and bruising.

Question 8

What is plasma?

Answer 8

A liquid that carries 1. Red and white blood cells and platelets. 2. Nutrients like glucose and amino acids - these are soluble products of digestion which are absorbed from the gut and taken to the cells of the body. 3. Carbon dioxide from organs to lungs. 4. Urea from liver to kidneys. 5. Hormones. 6. Proteins. 7. Antibodies and antitoxins produced by white blood cells.