TEAS 7 immune system

anatomy

Function

A complex network of cells, tissues, organs, & proteins that protect body from infection, disease, and other threats

Pathogens

A bacterium, virus, fungi, protists, worms, or other microorganism that can cause disease

White blood cells

Macrophages

Neutrophils

Eosinophils

Basophils

B cells

T cells

External protection 1st line of defense

first line of defense

• SKIN, mucous membranes

Internal protection 2nd line of defense

Second line of defense

• Macrophages (phagocytic WBC) non specific defense, mast cells contain histamine

EX. prick finger on thorn » bacteria enters body » mast cells assist with inflammatory response

-Histamine: Causes blood vessels to dialate (wide) near injury and makes it more permable to allow macrophages to engulf & digest pathogens

Complement system: Non specific or specifc immune defense help, compliment factor works to draw macrophages to the area with bacteria

Internal protection 3rd line of defense

Third line of defense

• B & T cells (Lymphocytes)

Adaptive immunity

Immunity that develops when a persons immune system responds to a foreign substance or microorganisms, such as after infection or vaccination

• Antigen made to tell your immune system if something is harmful in the body

Cell mediated

Cytotoxic T cells: WBC that destroys infected cells by causing apoptosis (self destruction)

Helper T cells: Helps activate other WBCs, also involved in humoral immunity

Cytotoxic T cell activation

Process 1: An infected cell presents an antigen from the pathogen that has infected it. Cytotoxic T cell binds & cause apoptosis

Process 2: Macrophages release chemical signals. Helper T cells bind & then release signals. Stimulates cytotoxic T cells.

Antibodies

A blood protein produced in response to & counteract a specific antigens

Found in: mucus, saliva, breastmilk, skin, lungs

IgG: MOST abundant type, enhances phagocytosis, neutralizes toxins, trigger complement system

IgA: Mucosal immunity

IgM: First antibody produced in response to infection, Forming complexes with antigens & activating complement

IgE: Allergic reactions & parasitic infections

IgD: Less understood antibody role in initiating early immune responses

Humoral

B cells- make antibodies

• ^can be activated by helper T cells or memory cells

Helper T cells: helps activate other white blood cells

Memory cells: stores memories of pathogens

Memory B cells: Activates plasma B cells to make antibodies

Memory T cells: Activates cytotoxic T cells

Active immunity

Antibodies produced in reponse to the presence of a pathgen

How is it aquired:

• Direct exposure to disease or vaccine induced immuity

Duration:

• Long lasting and/or lifelong protection

EX. Catching a cold receiving measles vaccine

Passive immunity

Given antibodies from another source rather than their own

How is it aquired:

• Natural: Breast milk, placenta

• Artificial: Immunoglobulin

Duration:

• Immediate protection but temporary

EX. Infant gets antibodies from mother rabies shot from animal bite