Unit 3- Non Specific Defenses

Question 1

What is a pathogen?

Answer 1

A bacterium, virus or organism that can cause disease.

Question 2

Describe physical defences.

Answer 2

Epithelial cells are closely packed providing the first line of defence provided the remain intact.

Question 3

Describe chemical defences.

Answer 3

Chemical secretions against pathogens: tears, Silvia, mucus, stomach acid
(Cry, Spit, Cough up, Puke)

Question 4

Describe the inflammatory response.

Answer 4

Histamine is released by mast cells causing vasodilation and increased capillary permeability. Increased blood flow leads to an accumulation of phagocytes and clotting elements at the site of infection.

Question 5

Describe phagocytosis.

Answer 5

Phagocytes engulf pathogens and destroy them by digestive enzymes contained in lysosomes.

Question 6

What are cytokines.

Answer 6

Protein molecules that act as a signal to specific white blood cells causing them to accumulate at the site of infection.