The Immune System

Lines of Defense

• 1. Skin and mucous membranes• 2.Celia in respiratory system• 3.Fever• 4.Mechanical actions (coughing,sneezing,etc.)• 5.White blood cells (lymphocytes)• 6.Interferon (fights viruses and cancers)

3 Factors to remember

• 1. Memory- response is quicker when the same antigen is introduced a second time

• 2. Specificity-Immunity is specific to 1 antigen. There are approximately 1 billion lymphocytes specific for approximately 1 million different antigens.

• 3. Recognition of non-self

Phagocytes

• These are feeding cells.• Macrophages are considered the “foot soldiers”

of the immune system• Duties of the macrophage:• A large feeding cell that can suddenly increase its

area in order to surround and enclose an enemy.• Shoots out a kind of sticky cytoplasm

(pseudopods) which adhere to bacteria in order to pull in its prey.

• Vacuums dead cells in system during an infection

• Releases interleuken 1 which alarms t cells• Produces growth factors which help to heal

tissue during infections• Produces enzymes which annihilate bacteria

Macrophage

Virus And Bacteria

Immune System on Alert

Cancer cell attacked by CD8 (Killer) cell

T cellsKiller t cell

T-cells attacking a cancer cell

Immunoglobulins

• Antibodies belong to a family of large molecules called Immunoglobulins

• IgG—coats microbes-crosses placenta• IgM-effective in killing bacteria—usually in blood

stream• IgE-protect against parasites-responsible for allergies• IgA-concentrates in body fluids-tears, respiratory

tract, digestive tract-guards entrances to the body-found in colustrum

• IgD-in umbilical cord

Anaphylactic Allergic Reaction