Fighting Disease

Question 1

List five feature of the human body that protects it from illness

Answer 1

1. The skin acts as a barrier to pathogens. It also secretes antimicrobial substances which kill pathogens.
2. Hairs and mucus in your nose trap particles that could contain pathogens.
3. The trachea and bronchi secrete mucus to trap pathogens.
4. The trachea and bronchi are lined with cilia. These are hair-like structures, which waft the mucus up to the back of the throat where it can be swallowed.
5. The stomach produces hydrochloric acid. This kills pathogens that make it that far from the mouth.

Question 2

What system in your body attacks pathogens if they make it into your body?

Answer 2

The immune system.

Question 3

What is the most important part of your immune system in regards to defending against pathogens?

Answer 3

White blood cells. They travel around in your blood and in every other part of you, constantly patrolling for microbes. When they come across an invading microbe they have three lines of attack.

Question 4

What three ways do white blood cells attack pathogens?

Answer 4

1. Consuming them. White blood cells can engulf foreign cells and digest them. This is called phagocytosis.
2. Producing antibodies.
   Every invading pathogen has unique molecules (antigens) on its surface. When some types of WBC come across a foreign antigen they will start to produce proteins called antibodies to lock onto the invading cells so that they can be found and destroyed by other WBC. The antibodies produced are specific to that type of antigen - they won’t lock on to any others.
   Antibodies are then produced rapidly and carried around the body to find all similar bacteria or viruses.
   If the person is infected with the same pathogen again the WBC will rapidly produce the antibodies to kill it - the person is naturally immune to that pathogen and won’t get ill.
3. Producing antitoxins - these counteract toxins produced by the invading bacteria.