A&P3 Exam 3 IMMUNITY

What is immunity?

The process that protects the body from injury and pathogens.

What is the immune system made of?

Proteins and cells; it does not have its own organs or tissues.

What are the three lines of defense?

1. Surface barriers 2. Cells and proteins of innate immunity 3. Cells and proteins of adaptive immunity.

What is innate immunity?

Nonspecific immunity that responds quickly to all pathogens the same way.

What is adaptive immunity?

Specific immunity that responds to specific antigens using T cells and B cells.

What is the difference between innate and adaptive immunity?

Innate = fast, nonspecific, initial response. Adaptive = slower, specific, develops memory.

What is immunological memory?

Lymphocytes and antibodies remember antigens for faster responses to future exposures.

What is cell-mediated immunity?

Adaptive immunity carried out by T cells.

What is antibody-mediated immunity?

Adaptive immunity carried out by B cells and antibodies.

What are surface barriers?

The first line of defense that prevents pathogens from entering the body.

What are the four surface barriers?

Skin, mucus membranes, protective secretions, and normal flora.

What does skin do?

Provides an external physical barrier against pathogens and mechanical trauma.

What do mucus membranes do?

Trap pathogens using sticky mucus; examples include the nasal cavity and respiratory tract.

What are protective secretions?

Stomach acid, enzymes in mucus, tears and saliva, and antimicrobial substances in sweat and sebum.

What is the function of sebaceous glands?

Secrete sebum, which deters pathogen growth.

What is normal flora?

Microorganisms that compete with pathogens and kill or deter the growth of other bacteria.

What is a hemopoietic stem cell?

A stem cell that develops into the different types of blood and immune cells.

What are the two stem cell lineages?

Myeloid stem cells and lymphoid stem cells.

Which cells develop from myeloid stem cells?

Mast cells, basophils, neutrophils, eosinophils, monocytes, macrophages, and dendritic cells.

Which cells develop from lymphoid stem cells?

Natural killer cells, T lymphocytes, and B lymphocytes.

What are phagocytes?

Cells that ingest foreign, infected, or damaged cells.

What is cytotoxic activity?

Releasing toxins to destroy cells or pathogens too large to phagocytize.

What are antigen-presenting cells (APCs)?

Cells that display part of an ingested pathogen's antigen on their cell membrane.

What are neutrophils?

Phagocytes that fight bacterial infections and are recruited early during inflammation.

What are eosinophils?

Cells that fight parasitic infections using cytotoxic effects.

What are macrophages?

Phagocytes that are activated early, ingest pathogens, and act as cytotoxic cells and APCs.

What are dendritic cells?

Specialized monocytes that act as APCs and trigger cell-mediated adaptive immunity.

What are basophils?

Non-phagocytes involved in inflammation and allergic responses.

What are mast cells?

Non-phagocytes involved in inflammation and allergic responses; recruit neutrophils and macrophages.

What are natural killer (NK) cells?

Non-phagocytes that destroy cancerous and virus-infected cells using cytotoxic secretions.

What else do NK cells do?

Activate macrophages.

What is the complement system?

Antimicrobial proteins that circulate inactive and are activated by enzymes.

What are the functions of the complement system?

Enhance inflammation and phagocytosis, neutralize pathogens, clear immune complexes, and cause cell lysis.

What is cell lysis?

The destruction or breakdown of a cell.

What are cytokines?

Chemical messengers that coordinate and regulate the immune response.

What do cytokines do?

Enhance immune responses, attract and stimulate phagocytes, inhibit viral replication, and induce flu-like symptoms.

What are interferons?

Cytokines that inhibit viral replication in neighboring cells and activate NK cells.

What are interleukins?

Cytokines involved in communication between immune cells; they help stimulate immune cell activity.

What causes an inflammatory response?

Cell damage or infection.

What happens first during inflammation?

Mast cells release inflammatory mediators.

What are inflammatory mediators?

Chemicals released by mast cells that coordinate the inflammatory response.

What are the three effects of inflammatory mediators?

Vasodilation, increased capillary permeability, and phagocyte recruitment.

What is vasodilation?

Widening of blood vessels to increase blood flow to the damaged area.

What is increased capillary permeability?

Capillaries become leakier, allowing fluid and immune cells to enter damaged tissue.

What are the four symptoms of inflammation?

Redness, swelling, heat, and pain.

What happens during the phagocyte response to inflammation?

Macrophages are activated and recruit neutrophils and monocytes.

How do neutrophils and monocytes differ?

Neutrophils rapidly increase; monocytes mature into macrophages, which are slower, live longer, and more aggressive.

What are lymphocytes?

Immune cells involved in adaptive immunity, including T cells and B cells.

Where are T cells produced and where do they mature?

Produced in bone marrow and mature in the thymus.

What type of immunity do T cells provide?

Cell-mediated immunity.

What happens to self-reactive T cells?

Self-reactive and non-immunocompetent cells are destroyed in the thymus.

What are naive T cells?

Unactivated T cells that circulate in blood and lymphoid tissues until they bind a specific antigen.

What are helper T cells (TH)?

T cells that activate and coordinate the immune response.

How are helper T cells activated?

Naive TH cells bind an antigen presented by an APC, undergo clonal selection, and differentiate.

What are memory TH cells?

Provide cell-mediated immunological memory for faster responses to future exposures.

What are effector TH cells?

Activated helper T cells that secrete cytokines; they are not phagocytic or cytotoxic.

What do effector TH cells stimulate?

Macrophages, activation and proliferation of TC cells, and stimulation and proliferation of B cells.

How do helper T cells and macrophages work together?

TH cells stimulate macrophages with cytokines; macrophages release cytokines that activate TH cells.

What are cytotoxic T cells (TC)?

T cells that destroy cancerous, foreign, and infected cells using cytotoxic effects.

How are cytotoxic T cells activated?

Through the same activation, clonal selection, and differentiation process as helper T cells.

What are effector TC cells?

Short-lived, active cytotoxic T cells that destroy target cells.

What are memory TC cells?

T cells that provide immunological memory.

What are B cells?

Lymphocytes that provide antibody-mediated immunity; produced and mature in bone marrow.

What happens to self-reactive B cells?

They are destroyed in the bone marrow.

How are B cells activated?

A B-cell receptor binds a specific antigen, then the B cell binds to a helper T cell and undergoes clonal selection.

What are plasma cells?

Differentiated B cells that secrete antibodies.

What are memory B cells?

B cells that produce antibodies upon subsequent exposure to the same antigen. (B cells that remember a pathogen and help make antibodies faster when it enters the body again.)

What are immunoglobulins?

Antibodies produced by plasma cells that bind specific antigens.

What are the four immunoglobulins on the slides?

IgG, IgA, IgM, and IgE.

What is IgG?

The only antibody that crosses the placenta; important in the secondary immune response.

What is IgA?

Found in breast milk and provides passive immunity to nursing infants.

What is IgM?

The first antibody to be secreted.

What is IgE?

Associated with parasitic infections and allergic reactions.

What is agglutination?

Clumping of cells.

What is precipitation?

Clumping of antigens.

What is opsonization?

Antibodies bind pathogens and activate phagocytosis.

What is neutralization?

Antibodies bind toxins and make them inactive.

What are the other antibody functions?

Complement protein activation and stimulation of inflammation.

What is the primary immune response?

The response to the first exposure to an antigen; slower and produces fewer antibodies.

What is the secondary immune response?

The response to a subsequent exposure to the same antigen; faster and produces more antibodies.

Why is the secondary immune response faster?

Memory B cells recognize the antigen from a previous exposure and produce antibodies more quickly.

What is active immunity?

The body's cells actively respond to an antigen; memory cells and antibodies form, and immunity can last a lifetime.

What is passive immunity?

Antibodies are passed to a person from another source; immunity is temporary.

What is natural active immunity?

Developed through natural exposure to an infection.

What is artificial active immunity?

Developed through vaccination.

What is natural passive immunity?

Antibodies passed from mother to baby through the placenta or breast milk.

What is artificial passive immunity?

Receiving antibodies through immunoglobulin injections.