The Immune System

Flashcards for reviewing the immune system lecture notes

Innate Immunity

Recognition and response rely on traits common to groups of pathogens

Adaptive Immunity

Recognition of traits specific to particular pathogens, using a vast array of receptors; slower response

Barrier Defenses

Skin, mucous membranes, secretions

Internal Defenses

Phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response

Humoral Response

Antibodies defend against infection in body fluids.

Cell-Mediated Response

Cytotoxic cells defend against infection in body cells.

Skin

Barrier to microbes; continuously shed, removing microbes

Mucous Membrane

Contain lysozymes; traps microbes

Phagocytosis

Ingestion of invading microorganisms by certain types of white blood cells

Phagocytes

Types of leukocytes that perform phagocytosis

Types of Phagocytic WBCs

Neutrophils, Macrophages, Eosinophils, Dendritic cells

Antimicrobial Proteins

Proteins that function by attacking microbes directly or by impeding reproduction

Interferons

Released by virally-infected cells; helps healthy cells resist infection

Inflammatory Response

Chemical signals released by macrophages (cytokines) and mast cells (histamines) cause capillaries to become more permeable

Natural Killer Cells

Attacks body cells that are virally infected or cancerous; releases chemicals that initiate apoptosis

Natural Killer Cells

Attacks body cells that are virally infected or cancerous; releases chemicals that initiate apoptosis

Key Characteristics of the Acquired Immune Response

The immune system must recognize an invader, launch an attack, and remember specific invaders

Antigen

Any foreign molecule that is specifically recognized by lymphocytes and elicits a response from them

Epitope

Accessible region of an antigen to which an antigen receptor or antibody binds

Two Main Types of Lymphocytes

B lymphocytes (B cells) and T lymphocytes (T cells)

Antibodies (or Immunoglobulins)

Y-shaped molecules made of light peptide chains and heavy peptide chains

Major Histocompatibility Complex (MHC)

T cells must bind to an antigen presented by infected cell or antigen-presenting cell

Class I MHC

Produced by infected body cells; presents to cytotoxic T cells

Class II MHC

Produced by antigen-presenting cells; Recognized by cytotoxic and helper T cells

Activated Helper T Cell

Secretes cytokines that stimulate other lymphocytes

Cytotoxic T Cells

Bind to virally-infected cells, cells infected by other internal parasites, cancer cells, and transplanted tissues

B Cells

Activated by cytokines secreted by helper T cells & antigens binding directly to B cells

Allergies

Exaggerated (hypersensitive) responses to antigens (called allergens)

Autoimmune Diseases

Conditions where antibodies and immune system cells mistakenly attack the body’s own cells