Jill's SI on Immune System

Question 1

What are the major functions of the immune system?

Answer 1

1) To defend against pathogens such as bacteria, fungi and pathogens
2) To regulate self, i.e. destroy dead or cancerous cells and remove debris

Question 2

Where can lymphoid tissues be found?

Answer 2

Strategically placed throughout the body in areas in close contact with the environment

Ex: tonsils & adenoids located near nose & mouth to respond to inhaled pathogens

Question 3

What is the purpose of lymphoid tissues?

Answer 3

1) Act as a host for high concentrations of immune cells
2) captures antigens and pathogens
3) together: increase likelihood that a specific B or T cell will “find” its antigen

Question 4

What do lymph nodes and spleen filter

Answer 4

lymph fluid, blood

Question 5

Why does inflammation occur?

Answer 5

Trauma, infection, cell death, intrusion of foreign materials

Question 6

What are the ways to activate the compliment system

Answer 6

1) Classical - through antibody - antigen binding

2) Alternative - through recognition of cell wall components

Question 7

What are the results of complement activation?

Answer 7

1) cell lysis via MAC
2) inflammation via C5a and C3a
3) opsonization (coating) of cells with C3b, can encourage macrophages to phagocytose cell

Question 8

Downstream effects of antibody-antigen binding: inactivates by—

Answer 8

1) Neutralization - masks dangerous bacterial exotoxins, viruses
2) Agglutination - clumping by cell-bound antigens
3) Precipitation - clumping of soluble antigens
4) Complement activation - via classical pathway

Overall, leads to: enhanced phagocytosis, inflammation (and complement leads to cell lysis)