Defense mechanisms

Question 1

What is an infection?

Answer 1

It is an interaction between a pathogen and our body’s defense mechanism.

Question 2

What is immunity?

Answer 2

Immunity is when our defense mechanism can kill a pathogen before it causes any harm due to specific memory cells present complementary to that same pathogen.

Question 3

What are the two types of defense mechanisms and their examples?

Answer 3

1. Non-specific: physical barriers and phagocytosis

2. Specific: Cell-mediated(T) and humoral response(B).

Question 4

Give differences between non-specific and specific mechanisms.

Answer 4

Non-specific
- immediate 
- shorter-lasting 
- same for all pathogens; non-specific 
Specific 
- Slower 
- longer lasting 
- specific

Question 5

How do white blood cells differentiate between self/non-self cells?

Answer 5

• Every cell has antigens

- Antigens are proteins on cell-surfaces with a specific tertiary site which makes every cell unique.

Question 6

What type of cells can white blood cells distinguish between?

Answer 6

1. Pathogens
2. Toxins
3. Non-self cells from the same species.
4. Cancer cells

Question 7

What is apoptosis?

Answer 7

Programmed death of a cell (lymphocytes complementary to body’s own cells that show an immune response to self-antigens)