U3: C10: Immune System Flashcards
Innate vs adaptive comparison (def only)
- innate: first line of defense, kills anything that doesn’t look right, is not specific to pathogen or antigen 2. adaptive: highly specific for a particular pathogen or antigen
Innate immune players
1: skin: natural flora, keratin layers 2. mucus membrane: traps pathogens in mucus, and cilia moves it out 3. Phagocytes: engulf pathogens 4. Natural Killer cells: destroy infected cells 5. Antimicrobial proteins: tears, interferons, complement 6. fever/inflammation: WBCs are more active at higher temperature, and inflammation recruits wbcs to sites of infection by sending out chemical signals and making capillaries more permeable.
Antimicrobial Proteins
innate immune system 1. tears (lyse bacteria), 2. interferons (interfere with virus replication), 3. complement (punches holes in cell/pathogen membrane),
Adative immunity players
- Antigen presenting cells (APC): 2. Antigen recognizing cells (ARC): T and B cells 3. Cytotoxic T cells: kill infected cells 4. Helper T cells: activate macrophages, T and B cells 5. B cells: produce antibodies 6. Memory cells: made and are more efficient (don’t need T cell activation) in proliferating and making antibodies for same infection in future.
Memory cells
allow the body to mount a greater, and more sustained response against the same pathogen during 2ndary response.
Anitbody mechanism for destroying pathogens
Antibody binding to antigen brings about.. 1. neutralization: pathogen can’t adhere to host cell 2. opsonization: makes it easier for phagocytosis 3. complement activation: kills infected cell by punching holes in cell membrane
Antibody and Antigen structure 1. Antibody 2. Antigen 3. Light vs Heavy chain 4. Binding region
Antibody (lock), Antigen (key) each antibody is specific to the binding of an antigen 1. Y shaped, with heavy and light chains. the tips of the fork bind antigen. Fork = hypervariable region = unique to each antigen-specific antibody.l 2. Presented by… a. pathogen enters APC b. pieces of pathogen displayed at the surface of APCs c. T cell receptors recognize the presented antigen, and activates various immune responses. 3. light chain and heavy chain linked togehter by disulfide bonds 4. hypervariable region (light and heavy chain)
Extracellular pathogen
- macrophage engulfs pathogen 2. pieces of pathogen become antigen and gets presented at the macrophage’s cell surface 3. helper T cell recognize the presented antigen, and activates macrophages to destroy pathogen. Helper T cells also activate B cells to produce antibodies against the pathogen.
Intracellular pathogen
- pathogen invade host cell 2. pieces of pathogen gets presented on the host cell surface 3. cytotoxic T cells recognize the presented antigen, and signals the infected cell to self destruct
Leukocytes origins and divisions
http://mcat-review.org/leukocytes.gif
Lymphocytes
T cell: cytotoxic T cell, helper T cell B cell: plasma cell, memory cell Natural killer cells
Phagocytes
neutrophil, macrophage, dendritic cell
Antigen presenting cells
Macrophages, Dendritic cells, B cells
Tissue x 4
bone marrow, spleen, thymus, lymph nodes
bone marrow
all blood cells arise from stem cells from here, B lymphocytes differentiate in the bone marrow
spleen
provides a site for WBCs to reside and proliferate, removes pathogens from blood, and grave yard for RBCs and platlets
* filers blood and lymph and storage area for blood
thymus
T lymphocytes differentiate occurs here
*secretes thymosin- hormoe that stimulates pre-T cells to mature
lymph nodes
provide a site for WBCs to reside and proliferate, remove pathoges from lymph. Residing lymphocytes monitor lymph for foreign antigens, and initiate an immune response when exposed to foreign antigens
*filter lymph and help attack bacteria and viruses
macrophage
myeloid -> monocyte phagocytose pathogens and APC
neutrophils
myeloid -> polymorphonuclear leukocytes phagocytose pathogens and destroy it
mast cells
myeloid release histamine during allergic response, bring about inflammation
NK cells
lymphoid kills infected & abnormal cells
B lymphocytes 1. matures 2. plasma cell 3. memory cell
- bone marrow B cells only form 2 and 3 after exposure to antigen 2. secrete antibody 3. stick around in case the same antigen attaks in the future
dendritic cells
myeloid -> monocyte best APC
T lymphocytes 1. matures where 2. cytotoxic T cell 3. helper T cell
- thymus 2. recognize antigen on infected cells, and signal for apoptosis 3. recognize antigen on APCs, and signal for activation of B & T cells, and macrophages
____ are the functional cells of the immune syste. They consist of ____ (neutrophil, eosinophil, basophil) & ____ (lymphocytes & monocytes)
leukocytes, granulocytes, agranulocytes
humoral immunity is mediated by ____. Function..
B cells. B cell proliferate to make plasma cells (antibodies) and memory cells
Cell mediated immunity is mediated by ____. Function..
T cells. 3 major classes (helper T cells, supressor T cells, and killer T cells (cytotoxic) (also a memory T cell)
Active vs passive Immunization
Active: results in a sustained immune response mediated by B cells (antibodies formed from by b cells) Passive: short lived response (injection of antibodies)
Natural vs artifical immunization
natural: exposure to antigen in nature or trasfer of anitbodies from mother to fetus Artificial: is an active immunization that uses weakend or dead forms of microbes to generate an immune response without causing active infection
Which (humoral/ cell mediated) immune system combat these pathogens best? 1. bacterial infections 2. viral infections 3. fungal infecctions
- humoral (B) 2. cell mediated (T) 3. cell mediated (T)
Adaptive Immunity: memory response
