The Immune System Study Guide

Flashcards covering key vocabulary and concepts related to the immune system, including its defenses, cells, and processes.

First Line of Defense

Mechanical barriers including skin and mucous membranes along with protective chemicals like sweat and mucous.

Second Line of Defense

Internal defenses such as phagocytes, natural killer cells, inflammation, and antimicrobial proteins.

Adaptive Immune System

The third line of defense characterized by a specific immune response to particular pathogens.

Opsonization

The process by which pathogens are marked for ingestion by phagocytes by binding to antibodies or complement proteins.

Respiratory Burst

A rapid release of reactive oxygen species from immune cells necessary to destroy engulfed pathogens.

Natural Killer Cells

Cells that directly kill virus-infected cells and tumor cells by releasing perforins and granzymes.

Cardinal Signs of Acute Inflammation

Redness, heat, swelling, pain, and loss of function at the affected area.

Leukocytosis

Increased production of white blood cells during phagocyte mobilization.

Interferons

Signaling proteins released by virus-infected cells to warn neighboring cells and enhance the immune response.

Complement System Functions

Includes enhancing phagocytosis, lysing pathogens directly, and stimulating inflammation.

Immunocompetence

The ability of lymphocytes to recognize and bind to specific antigens.

Self-Tolerance

The ability of the immune system to differentiate between self-antigens and non-self-antigens.

Positive Selection of T cells

Survival of T cells that can recognize self-MHC molecules.

Negative Selection of T cells

Elimination of T cells that bind strongly to self-antigens to prevent autoimmunity.

Primary Immune Response

Occurs upon first exposure to an antigen, characterized by a slow response and initial IgM antibodies.

Secondary Immune Response

Occurs upon subsequent exposures to the same antigen, characterized by a faster response and predominance of IgG antibodies.

Active Humoral Immunity

Results from exposure to antigens, such as natural infection or artificial vaccination.

Passive Humoral Immunity

Results from the transfer of antibodies, such as through breast milk or therapeutic antibody infusions.

Helper T Cells (CD4+)

Cells that assist other immune cells, crucial for regulating immune responses.

Cytotoxic T Cells (CD8+)

Cells that directly kill infected or cancerous cells.

Antigen Presenting Cells (APCs)

Capture and present antigens on their surface using MHC proteins to activate T cells.

MHC Class I Proteins

Found on almost all nucleated cells, presenting endogenous antigens.

MHC Class II Proteins

Found on professional antigen-presenting cells, presenting exogenous antigens.

Cytotoxic Granules

Contain perforins and granzymes released by cytotoxic T cells to destroy infected cells.

Regulatory T Cells (Tregs)

Cells that maintain immune tolerance by suppressing excessive immune responses.

Autoimmune Diseases

Conditions that occur when the immune system mistakenly attacks self-antigens.

Hypersensitivities

Allergic reactions that can be immediate, subacute, or delayed.