Human Defence System

Question 1

What are the parts of the non-specific defence systems?

Answer 1

Skin
Nose
Trachea & bronchi
Stomach

Question 2

What does the skin do in the prevention of pathogens entering the body?

Answer 2

Acts as a physical barrier

Glands secrete antimicrobial (oil) to kill microbes/pathogens

Question 3

What does the nose do in the prevention of pathogens entering the body?

Answer 3

Has hairs, sticky mucus and cilia which prevent pathogens entering through the nostrils to your lungs

Question 4

What does the trachea and bronchi do in the prevention of pathogens entering the body?

Answer 4

Respiratory system is lined with mucus to trap dust and pathogens. Cilia move the mucus upwards to be swallowed.

Question 5

What does the stomach do in the prevention of pathogens entering the body?

Answer 5

Produces hydrochloric acid which is pH1 so kills most ingested pathogens

Question 6

What happens if a pathogen is able to get past the non-specific defences and into the bloodstream?

Answer 6

The immune system tries to destroy with

Question 7

What is phagocytosis?

Answer 7

White blood cells (called phagocytes) engulf the pathogens and digest them.

Question 8

What does white blood cells producing antitoxins do?

Answer 8

Bacteria may produce toxins/poison.

White blood cells release specific antitoxins to neutralise the effect of the toxin.

Question 9

What do the white blood cells lymphocytes do?

Answer 9

White blood cells (called lymphocytes) identify the antigen on the pathogen.
-They make specific antibodies (a type of protein) to
destroy the pathogens. This can take time and so an
infection may occur.
-They also divide and differentiate into memory cells.
If a person is infected again by the same pathogen, the
memory cells make the antibodies much faster.