Chapter 8 Infection and Defects in Mechanisms of Defence

Question 1

Descriebe what infectivity id

Answer 1

The ability of a pathogen to invade and multiply in host

Question 2

Describe Virulence

Answer 2

The capacity of a pathogen to cause severe disease

Question 3

Describe pathogenixity

Answer 3

The ability of an agent to produce disease success depends on communicability infectivity, extent of tissue damage and virulence

Question 4

Describe toxicgenity

Answer 4

The ability to produce soluble toxins that influence the pathogens degree of virulence.

Question 5

Describe type 1 hypersensitivity reactions

Answer 5

Primarily triggered by IgE and related to environment. The main mediator of this reaction is histamine

Question 6

Describe type 2 hypersensitivity reactions

Answer 6

Generally against specific cells or tissues

Question 7

Describe Type 3 hypersensitivity reactions

Answer 7

These reactions are generally caused by antigen-antibody complexes that are formed in the circulation and deposited later in vessel walls or other tissues. They all specifically bind to an antigen

Question 8

Describe type 4 reactions

Answer 8

Theses are mediated by T cells and do not involve antibodies examples include tb test or graft rejection