Immune System

Question 1

What is the 1st line of defense?

Answer 1

Intact skin and mucous membranes

Question 2

What is the 2nd line of defense?

Answer 2

Innate Immunity: neutrophils/macrophages + complement proteins)

Question 3

What is the 3rd line of defense?

Answer 3

Acquired/Adaptive-Immunity (T-cells + antibodies proteins)

Question 4

Differences between innate VS. acquired immunity.

Answer 4

• No memory VS. memory
• Non-specific VS. highly specific
• Effective prior to exposure VS. after exposure
• No change in effectiveness after exposure VS. increase in effectiveness

Question 5

What are the 2 main components of acquired/adaptive immunity?

Answer 5

Humoral VS. Cell-mediated

Question 6

What is Humoral immunity mediated by?

Answer 6

Antibodies (immunoglobulins) produced by plasma cells (derived from B-cells)

B-cells (assisted by Helper T-cells) –> plasma cells –> antibodies (Ab’s)

Question 7

What is Cell-mediated immunity?

Answer 7

T-lymphocytes (helper + cytotoxic T-cells)

Question 8

What is the function of the Helper T-cell?

Answer 8

Along with macrophages, protect against bacteria/fungi/protozoa + help B-cells differentiate into plasma cells (which produce Ab’s)

Question 9

What is the Function of the Cytotoxic T-cell?

Answer 9

Defend against virus-infected cells

Question 10

Describe the process of Adaptive immunity with a virus.

Answer 10

Virus engulfed by macrophage.

Antigen presenting cell (macrophage) with a Class II MHC protein signals Helper T cell with the same antigen receptor.

TH cell is activated and releases cytokines.

IL-2 (type of cytokine) is a T-cell growth factor and it expands the population of TH cells specific for this antigen.

Cytotoxic T-cells and B-cells (memory and plasma) are also activated.

Question 11

What happens microscopically during inflammation?

Answer 11

Redness due to dilation of blood vessels. Inflammation from plasma entering tissue from the permeated blood vessels.

Question 12

What are the 2 forms of inflammation?

Answer 12

Pyogenic: pus producing, primarily involves humoral immunity (antibodies) and neutrophils

Granulomatous: primarily involves cell-mediated immunity (T-cells) and macrophages

Question 13

What are the functions of complement?

Answer 13

Increase vascular permeability causing edema and attracting neutrophils. Enhance phagocytosis and lysis of bacteria.

Question 14

What are the advantages of the immune system?

Answer 14

Protect against infection + mediates recovery from infection.

Question 15

What are the disadvantages of the immune system?

Answer 15

Hypersensitivity. Autoimmune disease. Symptoms of disease when infected cells are attracted.

Question 16

In immunopathogenesis, what causes the disease?

Answer 16

Immune response, not an organism.

Question 17

How does immunopathogenesis occur?

Answer 17

Antibody against the organism cross reacts with the host tissue. Cytotoxic T-cell kills the virus infected cells that would have died as a result of the virus itself.

Question 18

What are the 2 types of immunization?

Answer 18

Active: Immunize with the actual microbe which may be killed or a live, attenuate (weakened) microbe

Passive: Immunize with antibodies previously made in another person/animal

Question 19

What are the advantages of active immunization? Disadvantages?

Answer 19

Long Lasting; 7-10 days to become effective (not immediately protective)

Question 20

What are the advantages of passive immunization? Disadvantages?

Answer 20

Protects immediately; lasts short time (1 month) + only protects against infections for which antibodies are effective (no cell-mediated immune response)