The Human Defense System

Question 1

What is the function of the non-specific defence system?

Answer 1

Prevents pathogens from entering the human body.

Question 2

How does the skin prevent pathogens from entering the body.

Answer 2

The outer layer consists of dead cells, so it is hard for pathogens to penetrate.
The skin secretes an oily substances ( sebum ) which kills bacteria.

Question 3

How does your nose prevent pathogens from entering the body?

Answer 3

The nose is lined with hairs that trap pathogens.

Question 4

What are the small, hair-like structures that line the trachea and bronchi, which prevent pathogens from entering further inside the body?

Answer 4

The trachea and bronchi are lined with cilia.
The cilia are covered in mucus, which is wafted up to the back of the throat - where it is swallowed.

Question 5

How does the stomach defend against pathogens?

Answer 5

The stomach contains hydrochloric acid, which kills pathogens.

Question 6

What are the 3 functions of white blood cells in the immune system?

Answer 6

• Phagocytosis
• Producing antibodies
• Producing antitoxins

Question 7

What is the name of the process in which white blood cells engulf and digest pathogens?

Answer 7

Phagocytosis.

Question 8

How do white blood cells produce antibodies?

Answer 8

When white blood cells detect a foreign antigen, they will produce proteins called antibodies.
Each type of antibody is specific to one type of antigen.
Antibodies remain in the blood for a long time and can be produced rapidly, so if a person comes into contact with the same pathogen, they will be immune.

Question 9

Why do white blood cells produce antitoxins?

Answer 9

Antitoxins neutralise the toxins produced by pathogens.