Elements of the Immune System and Their Roles in Defense - Vocabulary

Vocabulary flashcards covering key terms from the lecture notes on the immune system.

Immunology

The study of the body's defense against infection.

Immunity

The protection the body gains after fighting a causative microorganism.

Vaccination

A procedure that prevents severe disease by exposing healthy people to an infectious agent in a form that does not cause disease.

Variolation

The introduction of material from smallpox pustules to healthy people.

Edward Jenner

A physician who deliberately infected people with cowpox to confer immunity to smallpox.

Vaccination origin

The practice of cowpox inoculation gave rise to the term vaccination (from Latin vacca, cow).

Louis Pasteur

Developed the first live attenuated vaccines (fowl cholera, rabies).

Live attenuated vaccines

Weakened strains of pathogens used to stimulate immunity.

Immunization

The stimulation of an immune response by deliberate inoculation with an attenuated pathogen.

Commensal microorganisms

Microbes that reside in the body without harming health.

Microbiota

The complete community of microbial species that inhabit the body.

Pathogen

Any microorganism that causes disease.

Virus

A microscopic infectious agent that replicates inside living cells.

Bacteria

Single-celled microorganisms; some cause disease.

Fungi

Eukaryotic organisms; some are pathogenic.

Parasites

Organisms that derive nutrients from a host and may cause disease.

Opportunistic pathogen

Microorganisms that are usually harmless but cause disease when the immune system is weakened.

SARS-CoV-2

Virus that causes COVID-19 infection.

HIV

Virus that attacks the immune system.

Staphylococcus aureus

A common bacterial pathogen.

Streptococcus pneumoniae

Bacterial cause of pneumonia.

Salmonella enterica

Bacterial cause of gastroenteritis.

Mycobacterium tuberculosis

Bacterium that causes tuberculosis.

Listeria monocytogenes

Bacterial pathogen often associated with foodborne illness.

Pneumocystis jirovecii

Opportunistic organism causing pneumonia in immunocompromised individuals.

Epidermophyton floccosum

Fungus causing skin infections.

Candida albicans

Fungus that can cause candidiasis.

Trypanosoma brucei

Protozoan parasite causing African sleeping sickness.

Schistosoma mansoni

Parasitic worm causing schistosomiasis.

Physical barriers

The body's first line of defense, including skin and mucous membranes.

Strong barriers

Skin, hair, and nails.

Fragile barriers

Mucosal membranes.

Innate immunity

The immediate, nonspecific defense against pathogens.

Adaptive immunity

The specific, learned immune response to pathogens.

Diversity

The variety of antigen receptors in the immune system.

Tolerance

The ability to avoid reacting to self-antigens.

Effector choice

The selection of effector mechanisms in an immune response.

Memory

Immunologic memory of past pathogens enabling faster responses on re-exposure.

Macrophages

Phagocytic cells derived from monocytes that engulf pathogens and secrete cytokines.

Polymorphonuclears

Neutrophils and other granulocytes that respond early to infection.

Mast cells

Cells that release histamine and other mediators during inflammation and defense against parasites.

Innate lymphocytes

NK cells and ILCs (ILC1, ILC2, ILC3) involved in innate immunity.

B lymphocytes

Lymphocytes that produce antibodies.

T lymphocytes

Lymphocytes that help B cells and kill infected cells; include helper and cytotoxic subsets.

Dendritic cell

Antigen-presenting cells that activate T cells and initiate adaptive immunity.

Plasma cell

Terminally differentiated B cell that secretes antibodies.

Monocyte

Circulating precursor to macrophages.

Phagocytosis

Engulfment and destruction of pathogens by cells.

Neutrophil

A type of polymorphonuclear leukocyte; a key first responder in infection.

Natural killer cell

Lymphocyte that kills virus-infected cells and some tumor cells.