Immune system

Pathogens examples

Bacteria virus, fungus, protists,worms

What is the first line of defense (nonspecific)

Skin and mucus membranes

Second line of defense (nonspecific)

macrophages: white blood cells, inflammatory responses

Mast cells

Type of white blood cell assisting with allergic and inflammatory responses containing histamine

What does histamine do?

a chemical released by mast cells during allergic reactions that dilates blood vessels and. Increases permeability.

Macrophages

Engulf and digest pathogens

Nonspecific immune response

Mechanism activated without knowing the exact nature of the threat

Third line of defense

Specific and Adaptive immune defense (viral infections) specific cells used to target infection

Two types of adaptive immunity

Humoral and cell mediated

Cell mediated adaptive immunity

a type of immunity that activates T cells to cause apoptosis (self-destruction of infected cell)

Helper T cells function

to assist in activating cytotoxic T cells, helping coordinate the immune response.

Humoral immunity

a type of immunity that involves B cells producing antibodies to neutralize pathogens and mark them for destruction.

Most abundant type of Antibody

is Immunoglobulin G (IgG). protecting against infection

First antibody produced in response to infection.

Immunoglobulin M (IgM), which is produced shortly after the initial exposure to an antigen.

Active immunity

When antibodies are produced in response to presence of pathogen.

How is active immunity acquired?

Exposure to pathogens or by vaccine. Ex. Common cold/ measles vaccines.

Duration of active immunity?

Long lasting or lifetime

What is passive immunity?

Given antibodies from another source

How passive immunity is acquired?

naturally – breastmilk, placenta containing antibodies, artificially- blood products like immunoglobulin therapy

Duration of passive immunity

Immediate protection,but temporary

Example of passive immunity

Antibody injections, like rabies shot, or breastmilk igA