P: week 2 Flashcards
what is the non-specific physical & chemical defences?
barriers = skin, mucous membranes, stomach acid, lysozyme in tears
expulsion = coughing, sneezing, vom, diarrhea
what are the barriers to invasion?
- non-specific physical and chemical defences
- innate immunity (natural)
- adaptive immunity (acquired)
what cells are involved with innate immunity?
macrophages, neutrophils, eosinophils, basophils, monocytes
what is involved in adaptive immunity?
cellular(cytotoxic)
humoral(antibodies)
T and B lymphocytes
what do B lymphocytes become?
B lymph -> plasma cell -> antibodies
which granulocytes circulate within the blood?
neutrophils, eosinophils and basophils
role of neutrophils?
recruited to sites of inflammation and bacterial infection
role of eosinophils and basophils:
involved in allergic inflammation and protection against parasitic infection
what granulocytes are within the tissue?
mast cells
role of mast cells?
facilitate inflammatory response, involved in allergic and anaphylactic reactions
what do monocytes do?
monocytes DIFFERENTIATE into macrophages - can reside within the tissue or travel within blood stream
ROLE: assist in phagocytosis and activation of bactericidal mechanisms and antigen presentation
location of dendritic cells and what immune response they are involved in:
initially reside within the tissue in contact with the outside environment
INNATE immune
roles of immune system?
- defense against infection
- defense against tumors
- can injure cells & induce pathologic inflammation
- recognize & responds to tissue grafts & newly introduced proteins
role of antigen:
- identify antigen
- engulf
- move to local lymph node present to lymphocytes
where do B & T cells reside?
circulate between blood and lymphoid tissues
B lymphocyte + antigen = ??
antibody secreting plasma cells
T lymphocytes + antigen = ??
effector T cells
what are macrophages role in lymph nodes?
destroy microorganisms & debris
what are lymphocytes role in lymph nodes?
activated & mount attack against antigens
what are the lines of defense in order?
- Skin (keratinization, very tight desmosomes, hair, sweat low pH)
- Innate - Non-Specific = fast,
- Adaptive = slow, memory
steps in phagocytosis
- bacteria
- phagosome
- phagolysosome
- digested bacteria
- release into extracellular
what are the classes of antibodies?
ig G - good memory ig M - same response everytime ig A ig E ig D
what happens after first line of defence fails?
first line = skin inflammation follows aiming to: 1. eliminating the initial cause of cell injury 2. remove necrotic cells & tissue 3. initiate process of repair
how is fibrin formed? and what is its role?
formed following cleavage of plasma protein fibrinogen
fibrin sticks platelets together to form clots
what is acute inflammatory response characterised by?
presence of lots of neutrophils
bacterial invasion attracts lots of neutrophils
how do neutrophils remove bacteria?
- release free radicals
- release lysosomal enzymes
how do leukocytes get to the site of injury from blood?
- migration = move to the periphery of blood vessel
- rolling = interacting with adhesion molecules
- adhesion = binds to single receptor
- diapedesis(transmigration) = migrate through
- chemotaxis = follow chemical gradient to site of injury
what are the 4 types of exudate?
- purulent = puss consisting of neutrophils(once neutrophils are at injury donot enter back into blood but die at the site and become puss)
- fibrinous = greater permeability - more fibrin
- serous = little protein in inflammatory fluid, less severe eg. blister
- Haemorrhagic = out pouring of blood
what influences outcome of acute inflammation?
- tissue type
- extent of damage
- type and duration
major events in acute inflammation
- increased blood flow (vasodilation)
- increased permeability (widening of intercellular gaps between endothelial cells)
- migration of neutrophils (capillaries & venules -> interstitial space)
role of fibrin:
network of fibrin prevents migration of micro-organisms, produces a scaffold which assists in the migration of neutrophils and macrophages through the damaged area
- Blood Clotting
what is inflammatory exudate?
protein rich fluid and cells that have escaped from blood vessels due to an increase in vascular permeability(like in inflammation)
role of inflammatory exudate?
- carries proteins, fluid an cells from local blood vessels into damaged area to mediate local defences
- components of the exudate are able to destroy the infective causative agent
role and origin of chemical mediators in inflammation
locally produced at site of inflammation or circulate in plasma as INactive precursors
their role is to orchestrate the acute immune response
major signs of acute inflammation and its cause:
redness = vasodilation increased blood flow
heat = “ “ “ “
pain = pressure effects on nerve endings and chemical factors
swelling = accumulation of exudate (permeability)
loss of function = damage of tissue swelling and pain
what is the acute phase response of inflammation?
release of chemical mediators that orchestrate the local result also causes systemic effects like fever, decreased appetite, increase pulse, leukocytosis = increase WBC(bone)
describe the subtypes of acute inflammation:
- purulent = large quantities of pus(neutrophil, necrotic cells, oedema)
- complication of purulent inflammation = abscess, localised area of tissue necrosis with live and dead neutrophils, fibrosis can wall off - fibrinous = vessels permeable to fibrin
- serous = outpouring of thin fluid(blisters)
- haemorragic = outpouring of blood from significant vessel damage
which is NOT an inflammatory exudate?
fibrous, fibrinous?
fibrous
define chronic inflammation?
inflammation of prolonged duration(weeks or months) in which active inflammation, tissue destruction and attempts to repair are proceeding simultaneously
types of inflammatory mediators:
- Plasma Inflammatory Mediators
- complement proteins
- kinins - ## Cell-Derived Inflammatory Mediators
cells in surrounding tissues?
dendritic cells
mast cells (contains histamine granules)
macrophages
role of histamine?
histamine released from mast cells in surrounding tissue triggers vasodilation and increase vascular permeability => WBC come to site pf injury
what do the macrophages do?
release cytokines which have local and systematic effects(fever WBC)
monocytes leave blood and enter surrounding tissue to become?
macrophages
outline the differences between acute and chronic responses:
duration
vascular change occurs in acute but not chronic
contents of cellular infiltrate
odema occurs in acute but not chronic
tissue destruction & repair happens constantly in chronic but not acute
where are lymphocytes made and matured?
B = Bone marrow T = Thymus
Both are made in bone marrow but T lymphocytes mature in thymus
T cells = cell mediated immunity function of T helper cells:
- produce cytokines, promoting the differentiation of B cells
- activate macrophages and T cytotoxic cells
the “help” the B cells (y)
function of T cytotoxic cells:
produce cytotoxic granules
kill antigens by release of perforin or via apoptosis
what is an epitope?
specific piece of the antigen that antibodies bind to
what do the surface receptors of T lymphocytes recognise?
they recognise antigen epitopes
what do surface receptors of B lymphocytes recognise?
recognise soluble antigens and antigens
what can activated B lymphocytes differentiate into? and what promotes this
plasma cells
cytokines produced by T lymphocytes promote this differentiation
ALSO
some remain as B memory lymphocytes
how do plasma cells form?
differentiate from B cells -> plasmablasts -> plasma cells
characteristics of plasma cells?
- eccentric nucleus (not center)
- basophilic cytoplasm
- antibody production
what are common morphologic patterns of chronic inflammation?
- chronic non-suppurative inflammation
- chronic suppurative inflammation
- granulomatous inflammation
what does cell infiltration of chronic inflammation consist of?
macrophages lymphocytes plasma cells eosinophils multinucleated giant cells
