Immune System-Brianna Mayorga p.6
Location of Lymphatic Organs & their Functions
Purpose & Examples of 1st, 2nd, & 3rd Lines of Defense
Innate Immune Defense & Adaptive Immune Defense
Humoral Response & Cellular Response
Antigens & Antibodies
Passive VS Active Immunity
Cells in Immune System & their Functions
Disorders Associated with the Immune System
Innate ( nonspecific) defense system: first & second lines of defense; first- external body membranes ( skin & mucosae); second- antimicrobial proteins, phagocytes, & other cells ( inhibit spread of invaders)
Adaptive ( specific) defense system: third line of defense; attacks particular foreign substances ( takes longer to react)
Phagocytes: white blood cells that ingest and digest foreign invaders
Neutrophils: most abundant type of phagocyte; dies fighting; when exposed to infected material becomes phagocytic
Macrophages: develop from monocytes which are chief phagocytic cells; from the bone marrow
Natural Killer Cells: non phagocytic cells; lymphocytes that police blood & lymph; kills by inducing apoptosis; secretes potent chemicals which generates inflammatory responses
Inflammation: triggered whenever body tissues are injured; due to trauma, heat, irritating chemicals, & infections
Pus: dead neutrophils, tissue/cells, & living/dead pathogens
1st line of defense: surface barriers such as skin a mucous membrane; produce protective chemicals that inhibit or destroy microorganisms; (chemicals produced: acid, enzymes, & mucin); example: hairs in nose trap inhaled particles
2nd line of defense: if microorganisms invade deeper then phagocytes( digest & ingest foreign invaders), natural killer cells( kills cancer & virus-infected cells before the immune system is activated), inflammatory response( whenever body tissues are injured), antimicrobial proteins( proteins released by virus cells then act as messengers to protect unaffected cells), & fever( systemic response initiated by pyrogens); many of these have pattern recognition receptors which bind to structures and disarm them before they do any harm
Humoral: antibodies, produced by lymphocytes, circulate freely in body fluids; bind temporarily to target cell; mark for destruction
Cellular: lymphocytes act against target cell; directly( by killing infected cells); indirectly( releases chemicals that enhance inflammatory response, activates lymphocytes &/or macrophages)
Antigens: substances that can mobilize adaptive defenses & provoke an immune response; targets all of adaptive immune responses; complex molecules not normally found in the body
Self-antigens: cells covered with variety of proteins on surface that are of antigens to self; one set of self-proteins are (MHC proteins)
Lymphocytes
T lymphocytes ( T cells)- cellular immunity
B lymphocytes ( B cells)- humoral immunity
Antigen-presenting cells: do not respond to specific antigens; essential auxillary roles in immunity
Dendritic cells: in CT & epidermis; mobile sentinels of boundary tissues; most effective antigen presenter known
Macrophages: develop from monocytes which are chief phagocytic cells; from the bone marrow
B lymphocytes: present antigens to helper T cell to assist own activation
Active: when B cells encounter antigens & produce specific antibodies against them ( 2 types: naturally & artificially acquired)
Naturally: formed in response to actual bacterial or viral infection
Artificially: formed in response to vaccine of dead or attenuated pathogens
Passive: when ready-made antibodies are introduced into body; protection ends when antibodies degrade
Naturally: antibodies delivered to fetus via placenta or to infant through milk
Artificially: injection of serum
3rd line of defense: specific defensive system that eliminates almost any pathogen or abnormal cell in body
Antibodies: proteins secreted by plasma cells; binds specific with antigen detected B cells
T cells: provide defense against intracellular antigens; can directly kill cells that have been infected
CD4 cells: some become helper T cells which can activate B cells; some become regulatory T cells which moderate immune responses
CD8 cells: can become cytotoxic T cells which are capable of destroying cells like foreign antigens
Immunodeficiency: congenital or acquired conditions that impair function or productions of immune cells
Severe combined immunodeficiency syndrome: genetic defect with marked deficit in B & T cells
Hodgkin's disease: acquired immunodeficiency that causes cancer of B cells
Acquired immune deficiency syndrome( AIDS) / Human immunodeficiency virus: cripples immune system by interfering with activity of the helper T cells
Autoimmune disease: when immune system loses ability to distinguish self from foreign
Autoimmunity: antibodies & sensitized T cells that destroys body tissues
