Human Defence Systems

Question 1

Explain the mechanisms that stop pathogens entering the body via the trachea and bronchi.

Answer 1

Mucus traps pathogens.
Cilia waft mucus and pathogens up to the throat.
Mucus and pathogens get swallowed and destroyed by the stomach acid.

Question 2

Explain how lymphocytes aid phagocytosis.

Answer 2

Lymphocytes produce antibodies that bind to antigens on the pathogen.

This makes them clump together.

Phagocytes can more easily engulf and digest pathogens.

Question 3

What is the purpose of antitoxins?

Answer 3

Antitoxins neutralise toxins produced by pathogens.

Prevents toxins damaging cells and therefore prevents symptoms / illness.