Ch. 8: The Immune System Flashcards
innate immunity
immunity defenses that is are
- always active
- nonspecific to invaders
NONSPECIFIC immunity
adaptive immunity
immunity defenses that target specific pathogens with immunologic memory
SPECIFIC immunity
where are leukocytes produced
the one marrow
B-cells
- produced in bone marrow
- activated in spleen/lymph nodes
- turn into plasma cells
- produce antibodies
humoral immunity
antibodies in the blood rather than the cells
B-CELLS
T-cells
- produced in the bone marrow
- mature in the thymus
cell mediated immunity
coordinate immune system and directly kill infected cells
T CELLS
lymph nodes
- filter lymph
- immune system responses can be mounted
- *not glands**
gut-associated lymphoid tissue (GALT)
immune tissue in close proximity to digestive system
- tonsils
- adenoids
- Peyer’s patches (small intenstine)
- aggregates in the appendix
what occurs during hematopoiesis
leukocytes are produced in the bone marrow
granulocytes
contain granules that are released via exocytosis as part of the immune response
- neutrophils
- eosinophils
- basophils
agranulocytes
- lymphocytes
- monocytes
defensins
antibacterial enzymes found on skin
lysoszyme
enzyme secreted by mucus membranes around the eye and oral cavity
complement system
nonspecific immunity response that punches holes in bacterial cell walls
interferons
proteins produced in cells infected with viruses that prevent viral replication and dispersion
resident population
permanent rather than transient cell group in a tissue
functions of a macrophage
- phagocytizes invader through endocytosis (envelope)
- digests invader using enzymes
- presents pieces of invader to other cells through MHC
MHC
major histocompatibility complex
protein that binds to an antigen and so it can be recognized by the adaptive immune system
cytokines
released by macrophages
stimulate inflammation and recruit immune cells
MHC - I
endogenous pathway: binds antigens that come from inside cells
all nucleated cells
MHC - II
exogenous pathway: binds antigens originate from outside cells
antigen-presenting cells: macrophages, dendritic cells, B-cells, some epithelial cells
antigen
substance that can be targeted by an antibody
Natural Killer (NK) cells
lymphocytes that recognize down regulation of MHC and induce apoptosis on viral infected cells
pattern recognition receptors (PRR)
recognize the category of invader for appropriate response
toll-like receptors (TLR) are the best-described
function of neutrophils
phagocytes that target bacteria using chemotaxis
detect chemicals bacteria give off and move up chemical gradient toward them
what does it mean to be opsonized
marked with an antibody from a B-cell
function of eosinophils
allergic reactions and parasites
release histamine –> inflammation and vasodilation –> immune cells move out of blood stream and into tissues
basophils
mast cells
release histamine –> inflammatory response
what produces antibodies/immunoglobulins
B-cells
what occurs after antibodies bind to antigens in free fluid
IN FLUIDS
- opsonization (attract other leukocytes for phagocytosis)
- aggluination (pathogens clump together to be phagocytized)
- block pathogen from invading tissues
what occurs after antibodies bind to antigens on the cell surface
B-CELL
- cell activates, proliferation and memory cells
MAST CELL
- degranulation
how many chains in antibodies
two heavy, two light held together with disulfide linkages
where is the antigen-binding region
the tip of the Y
clonal selection
mechanism for generating antibody specificity to antigen
isotype switching
process in which cells change which isotype of antibody they produce when stimulated by a specific cytokine
plasma cells
type of B-cell that produces a large amount of antibodies
memory b-cells
type of B-cell that stays in the lymph node and awaits reexposure to the same antigen
primary response
initial activation of antibodies to a new antigen. takes 7-10 days.
secondary response
rapid production of antibodies by memory cells when exposed to an antigen for the second time
positive selection
only allowing maturation of t-cells that can respond to the presentation of antigen on MHC
failing positive selection = t-cell can’t respond to antigens
negative selection
causing apoptosis in cells that are self-reactive
failing negative selection = t-cell can respond to self-antigens
thymosin
hormone in the thymus that facilitates maturation of t-cells
Helper T-cells
CD4+ T-cells
- coordinate immune response by secreting lymphokines
- respond to MHC-II antigens
lymphokines
secreted by helper t-cells
recruit other immune cells and increase their activity
Cytotoxic T-Cells
CD8+ T-cells
- directly kill virally infected cells by injecting chemicals that promote apopotosis
- respond to MHC-I antigens
Supressor T-Cells
Regulatory T-Cells
similar to helper t-cells, but also tone down immune response after infection has been contained
self-tolerance
turning off of self-reactive lymphocytes by suppressor t-cells to prevent autoimmune disease
memory t-cells
wait until exposure to a known antigen
first step of defense in bacterial infection
macrophages attack
first step of defense in viral infection
interferons released
self antigens
proteins and carbohydrates on the surface of every cell that signal (under nl conditions) that cell is domestic and should not be attacked
autoimmunity
attack on selfantigens
allergy reactions
attack on harmless foreign antigens
active immunity
immune system is stimulated to produce antibodies against specific pathogens, which are then stored in memory
passive immunity
transfer of antibodies to an individual
ex: transfer of antibodies across placenta during pregnancy
in what direction do lymphatic vessels become larger
as they move toward the center of the body
what (most) do lymphatic vessels join
thoracic duct
thoracic duct
duct in posterior chest that delivers lymph to circulatory system
how do lymphatic vessels contribute to fluid drainage
vessels drain fluid that remains in tissues back (due to osmotic pressure < hydrostatic pressure at venous end of capillaries) into the circulatory system
what do lacteals transport
fats packaged by the intestines
germinal centers
collections of B-cells in the lymph nodes
