Immune System Flashcards

Flashcards on the Immune System, Pathogens, Infection, and Immunity

Bacteria

Small, single-celled prokaryotes that use your body for food or produce toxins to make you sick.

Viruses

Small protein-encapsulated particles containing RNA or DNA genomes that need host cells to replicate; this can destroy cells or alter their behavior, which makes you sick.

Parasites

Fungi, protists, and worms that typically use your body for food, use you to replicate in, are toxic, or you are allergic to them or their spores.

Virulence

Ability to grow.

Invasiveness

Ability to enter.

Pathogenicity

Ability to harm.

Reservoir

The natural environment where the pathogen lives; can be human, animal, or environmental, such as soil or water.

Portal of Exit

How the pathogen leaves its natural reservoir; if the reservoir is human, the portal of exit may be saliva, mucous, blood, feces, nose discharge, etc.

Mode of Transmission

How a pathogen is transmitted to another; includes direct transmission (physical contact) and indirect transmission (insect or animal bites).

Portal of Entry

How a pathogen enters the body; can occur through penetration (cuts), inhalation (breathing in), or ingestion (eating).

Susceptible Host

The person at risk of infection; various factors influence the severity of infection, including immune health and speed of replication.

Innate immune system

Fast and non-specific immune system.

Adaptive immune system

Slower but highly specific immune system that can lead to long-term immunity against a pathogen.

Skin

Thick layer of dead cells in the epidermis that acts as a physical barrier.

Mucous membranes

Produce mucus that traps microbes.

Lysozyme

Enzyme in tears, sweat, and saliva that acts as a natural antibiotic.

Macrophages

Roam freely through your body to seek and destroy pathogens.

Neutrophils

Typically "called" to a site of infection to engulf and destroy pathogens; pus is typically composed of dead and alive neutrophils.

Natural Killer Cells

Leukocytes that recognize healthy and unhealthy body cells (infection or cancer).

Mast Cells

White blood cells found in mucous membranes and connective tissues that release cytokines that encourage inflammation.

Antigens

Chemicals on the surface of the pathogen that are recognized as foreign.

Antibodies

Proteins that can recognize specific antigens.

Lymphocytes

Special leukocytes that possess unique antibodies on their membranes.

Humoral Immunity

B cells

Cell-mediated Immunity

T cells

Memory Cells

Long-living cells that produce low levels of antibodies that circulate through the body.

Active Immunity

Immunity that involves the production of antibodies by the body itself and the transfer to memory cells; results in long-term immunity.

Natural Active Immunity

Creation of antibodies to a specific pathogen as a result of infection by the actual pathogen.

Artificial Active Immunity

Creation of antibodies to a specific pathogen as a result of exposure to a weakened pathogen; vaccination.

Passive Immunity

Immunity that involves the receiving of antibodies from another source; does not involve memory cells; only results in short-term immunity.

Natural Passive Immunity

Receiving natural antibodies from another organism, such as a mother to her newborn infant.

Artificial Passive Immunity

Receiving manufactured antibodies by external delivery methods, such as passive vaccines; transfusions & vaccines.

Vaccine

Induce long-term immunity to a specific pathogen by stimulating the production of immune memory cells; is a weakened form of the pathogen that contains antigens but cannot trigger the disease.

Herd Immunity

Vaccination not only gives immunity to the individual, but also indirectly protects non-vaccinated people.

Edward Jenner

An English physician who created the world’s first vaccine - to the smallpox virus in 1796.

Allergies

Exaggerated sensitivities to harmless antigens in the environment.

Allergens

Antigens that cause allergic reactions.

Histamines

Cytokines released by mast cells that cause the symptoms of allergy.