Immune System

Immune System

A complex network of cells, tissues, and organs that work together to defend the body against harmful invaders.

Antigen

Substances that cause the body to elicit an immune response and produce antibodies to fight them off.

Antibody

Immunoglobulins (proteins) usually found in the blood that detect antigens and bind to them and destroy them.

Active Immunity

Immunity acquired by infection or artificial means such as vaccination.

Passive Immunity

Maternal antibodies transferred from mother to fetus (across placenta, or through breast milk)

Inflammation

Defense response to stimuli causing a protective vascular connective tissue reaction.

Histamine

First chemical mediator in an immune and inflammatory response.

Hypersensitivity

A pathologic immune response to an antigen, causing an exaggerated response to the environment that results in disease/damage to the host.

Airborne Transmission

Spread via aerosol particles.

Droplet Transmission

Spread by respiratory droplets from coughing, sneezing, talking.

Contact Transmission

Spread by direct or indirect transmission.

Neutralization (Antibodies)

Binding to the pathogen and render it ineffective.

Antibody Opsonization

Where a pathogen becomes marked for ingestion and destruction by a phagocyte.

Complement System

System that enhances the inflammatory response by increasing vascular permeability, promoting chemotaxis, encouraging phagocytosis, and helping breakdown foreign cells.

IgG

Most common antibody in blood, protective against viral and bacterial infections.

IgM

First antibody to increase during initial (primary) immune response.

IgE

Antibody present in allergic responses, causes the release of histamines.

IgA

Effective against respiratory and GI tract microbes.

IgD

Works with B cells.

Innate Immunity

Natural/Non-Specific immunity; 1st and 2nd line of defense, includes barriers, secretions, phagocytotic WBCs, inflammation, and fever.

Acquired Immunity

Developed/Specific immunity; 3rd line of defense, production of specific antibodies (B cell and T cell action) to be stored for memory.

Granulocytes

Present in non-specific immunity; includes neutrophils, eosinophils, and basophils.

Agranulocytes

Present in non-specific immunity; includes lymphocytes and monocytes.

T Cells

Present in specific immunity; includes cytolytic (“killer”) T cells (CD8 lymphocytes) and helper T cells (CD4 lymphocytes)

Cytolytic T Cells

Attack and destroy cells directly.

Helper T Cells

Activates cytolytic cells & stimulate B cells to mature; also promote hypersensitivity reactions for defense.

B Cells

B lymphocytes: make antibodies.

Memory B Cells

Stored, dormant B cells to be triggered for a future antigen-specific response.

Active Natural Immunity

Natural exposure to antigen (e.g. chickenpox; flu, measles), development of antibodies after recovery from sickness.

Active Acquired Immunity

Antigen purposefully introduced to body (vaccine immunization), stimulation of antibody production (booster shots).

Passive Natural Immunity

Maternal antibodies transferred from mother to fetus (across placenta, or through breast milk), protection of infant for first few months of life.

Passive Artificial Immunity

Antibodies passively (unintentionally) obtained through injection of serum, short-term protection.

Acute Inflammation

Inflammation lasting days to a week.

Chronic Inflammation

Inflammation lasting months to years.

Vasodilation (Inflammation)

Widening of blood vessels, occurs during inflammation.

Edema

Fluid in interstitial space, caused by histamine.

Bronchoconstriction

narrowing of the airways in the lungs, caused by histamine.

Pruritus

Itching, stimulated by sensory peripheral nerve endings due to histamine.

Type 1 Hypersensitivity

IgE mediated, immediate, allergic, anaphylactic hypersensitivity due to histamine production.

Type 2 Hypersensitivity

Tissue-specific, cytotoxic hypersensitivity reaction – destruction of tissues due to an antigen on the membrane.

Measles

An example of an antigen that spreads via airborne routes of transmission.

Tuberculosis (TB)

An example of an antigen that spreads via airborne routes of transmission.

Varicella (Chickenpox)

An example of an antigen that spreads via airborne routes of transmission.

Influenza Virus

An example of an antigen that spreads via droplet routes of transmission.

Pertussis (Whooping Cough)

An example of an antigen that spreads via droplet routes of transmission.

Meningococcal infection

An example of an antigen that spreads via droplet routes of transmission.

Direct Contact Transmission

Spread by blood or other blood-containing fluids entering a person’s mucous membrane or breaks in the skin.

Indirect Contact Transmission

Involves transfer of an infectious agent through a contaminated object (cups, utensils, blankets).

Inactivated Virus

Virus that is bound by antibodies.

Hypersensitivity Reactions

Sneezing, coughing, itching, etc.

Vaccine immunization

An example of active acquired immunity.

Immunosuppressive drug therapy

Medication given to prevent the immune system from attacking the transplanted organ.

AIDS

Acquired Immunodeficiency Syndrome, terminal stage of HIV infection.

HIV

Virus that causes AIDS.

Anaphylactic shock

A severe, potentially life-threatening allergic reaction, caused by Type 1 Hypersensitivity

Urticaria

Hives, caused by Type 1 Hypersensitivity

Rhinitis

Runny nose, caused by Type 1 Hypersensitivity

Hemolytic anemia

Example of Type 2 Hypersensitivity.

Laceration

An example of a trauma, which can cause inflammation.

Burns

Can result in inflammation.

Chemical Irritants

Can result in inflammation.

Infection

Can result in inflammation.

Autoimmunity

Can result in inflammation.

Tissue Typing

Tests conducted to ensure tissue compatibility in organ transplants.

Graft

Transplanted organ.