Immune system Flashcards
functions of the immune system
- defending against invading pathogens
- removing worn out cells and tissue damage
- preparing for wound healing/tissue repair
- immune surveillance
pathogens
-disease producing microorganisms
immune surveillance
-identification and destroying abnormal cell that have originated in the body
leukocytes
- carry out major actions of the immune system
- include neutrophils, eosinophils, basophils, monocytes, and lymphocytes
- reinforced by plasma protein
- cell up cellular debris, preparing for tissue repair
immunity
- the body’s ability to protect itself by resisting or eliminating potentially harmful foreign invaders
- innate and adaptive responses
innate response
- nonspecific, born with it
- responds that non-selectively defend against foreign material
- first line defense
- works immediately
includes: inflammation, interferon, NK cells and complement system
adaptive response
- specific (lymphocytes, b and t cells)
- selectively target particular invader
inflammation
- nonspecific response to foreign invasion/ tissue damage
- mediated by phagocytes
inflammation function
- isolate, destroy, inactivate the pathogen
- remove debris
- prepare for healing and repair
cardinal signs of inflammation (PRISH)
- dolor (pain)
- rubor (redness)
- function laesa (loss of function, inflammation) (might happen)
- tumor (swelling)
- calor (heat)
interferon
-released by virus-infected cells and inhibits viral multiplication in other cells
natural killer cells
-lyse and destroy virus infected cells and cancer cells
complement system
- directly destroys the foreign invaders by lysing their membranes
- enhances inflammation
adaptive immunity
- includes antibody- mediated immunity
- cell-mediated immunity
antibody-mediated immunity
- the production of antibodies by B-lymphocyte derivatives (plasma cells)
- each B-lymphocyte has surface receptors for the binding of one particular type of antigen
- antigen stimulates B-cells to convert into plasma cells that produce antibodies
- produce memory cells
cell-mediated immunity
- the production of activated T lymphocytes
- directly attack unwanted cells
T cells in thymus
- pre T cells then thymus
- self vs. non-self
- selection: positive and negative
- negative: cells get deleted
- positive: cells mature
B cell characteristics
- from bone marrow
- antibodies inserted in the plasma
- highly specific
- formation of memory cells
- antibody-mediated
- bacteria
- short life span
T cells characteristics
- from bone marrow
- matured in thymus
- highly specific
- bind with self-antigen, like virus-infected cells
- cell-mediated
- cytokines
- long life span
- lyse virus-infected and cancer cells
- CD4 and CD8
memory cells
- produce faster, stronger secondary response
- subsequent exposure to same antigen
- remain in system
antibody structure
- Y shaped molecules
- antigen binding sites on the tip of each arm
- determine which antigen the antibody can combine
- tail determines what the antibody does when it binds with the antigen
- IgM, IgG, IgE, IgA, IgD
antibody function
- do not directly destroy antigenic material
- effect through neutralization or agglutination or by intensifying innate immune response
- activate complement system, enhance phagocytosis, stimulate NK cells
agglutination
-clumping of antigenic cell
opsonization
-enhancement of phagocytosis
primary immune response
- initial contact with a microbial antigen
- delayed for several days until plasma cells are formed
- peaks: couple of weeks
- memory cells produced
- clonal selection theory
secondary immune response
- the same antigen reappears memory cells produce rapid, more potent, and longer lasting secondary response
- prevents/minimizes infection forming long-term immunity against a specific disease
IgG
- 80-85%, most common
- only one that crosses placenta
- IgG levels will do down, baby will make own antibodies, takes time
- secondary immune response
IgA
- mucosal areas
- saliva
- tears
- breast milk
IgD
- antigen receptor on B cells
- activates basophils and mast cells
- produce antimicrobial factors
IgE
-allergies and parasitic infections
IgM
- early stages of B cell-mediated (humoral) immunity before there is sufficient IgG
- primary immune response
cell-mediated immunity
- T cells bind directly with target
- antibodies are not produced
- activated by a foreign antigen when on “self” cell
- self- antigens aka major histocompatibility complex (MHC) molecules (markers)
class I MHC self-antigens
- cytotoxic T cell
- CD8+
class II MHC self- antigen
- helper T cell
- CD4+
types of T cells
- cytotoxic
- helper
- regulatory
cytotoxic T cells
- targets virally invaded cells and cancer cells
- releases perforin into the membrane
- releases granzymes
perforin
- cytotoxic T cells
- creates a hole punching complex that inserts into the cell
granzymes
- cytotoxic T cells
- trigger cell to undergo apoptosis
helper T cells
- bind with other immune cells
- release cytokines that enhance the activity of other cells
regulatory T cells
- secrete cytokines
- suppress other immune cells ensuring the immune system does not overact
immune disease
- immunodeficiency
- inappropriate immune attacks
immunodeficiency disease
- characterized by insufficient immune response
- congenital or acquired
- impairment of antibody- mediated, cell- mediated or both
- HIV leads to AIDS
inappropriate immune attacks
- characterized by excessive or inappropriate immune responses
- allergies: against harmless environmental substances
- two types: immediate and delayed hypersensitivities
severe combined immunodeficiency
- congenital condition
- person born without B and T cells
immediate hypersensitivities
- involving the production of IgE antibodies by B cells
- within 20 minutes
- antibody-mediated immunity
- B cells, IgE, mast cells, basophils, histamine
delayed hypersensitivities
- more slowly responding T cells against the allergen
- TB test
- 1-3 days
- cell- mediated immunity
- T cells
external defenses
- body surfaces exposed to the outside environment serve as mechanical barriers
- enter through digestive, urogenital or respiratory system
- nonspecific immune strategies
acquired immunity
- naturally acquired
- artificially acquired
naturally acquired
- active: infection, contact with pathogen
- passive: antibodies passed from the mother
artificially acquired
- active: vaccine of active virus
- passive: ready made antibodies, gamma globlin
