introduction to clinical sciences Flashcards
autopsy types
hospital <10%
medico-legal >90%
acute vs chronic inflammation cells
acute – neutrophil polymoprhs
chronic – macrophages + lymphocytes
lifespan of neutrophils, macrophages and lymphocyes
neutrophils- hours
macrophages - weeks - months
lymphocytes - weeks-years
endothelial cells’ reaction when inflammed
sticky- other cells stick to it
gaps- increased vascular permeability – protein leaves– swelling
granuloma =
occurs in chronic inflammation
macrophages (endotheloid cells) surrounded by lymphocytes
harmful stuff walled off
options for damaged tissue
RESOLUTION = damaging factor removed. the tissue is undamaged or able to regenerate
REPAIR = damaging factor remains. the tissue is damaged and can not regenerate
– fibrous tissue replaces damaged tissue. fibroblasts –> collagen
REGENERATION. - healed
which cells are able to regenerate
pneumocytes
hepatocytes (but contined damage leads to cirrhosis - much fibrosis)
osteocytes
skin epithelium (but collagen causes scar)
gut epithelium
which cells are unable to regenerate
neurones - brain + spine
myocardial cells
cilia in organ of corti
these are non-dividing tissues
laminar flow
is this in arteries or vein
in centre of vessel
arteries . in veins, the speed is slower so blood drops with gravity
reperfusion injury
ischaemia
cells = :/
blood flow increases
cells dont readjust/cope. they produce damaging chemicals
so sometimes patients are kept cold/in coma until adjusted to avoid this
Which organs have multiple blood supply
what does this prevent
infarction (hopefully)
lungs
liver
circle of willis
apoptosis mechanism
enzymes released
cell shrinkage inc nucleus shrinkage
macrophage engulfs
the effectors are capases (these are switched on or off by proteins)
what triggers apoptosis
cosmic rays, UV —-> DNA damage
DNA damage
- strands broken
- base alteration
- cross linkage
this damage is detected by p53 gene
name 2 examples in physiology where apoptosis is seen
1 developement : trim down webbed digits to elegant fingers
2 high cell turnover areas - eg villi
name 2 examples in pathology where apoptosis is seen
1 too much apoptosis – HIV
2 not enough apoptosis – cacner
name 4 causes of necrosis
(traumatic cell death)
infarction
venom
frost bite
pancreatitis
what are the 3 types of necrosis
coagulative necrosis – more viscous
liquifactive necrosis – more runny
caseous necrosis – looks like soft cheese (TB)
hypertrophy
increased size of tissue due to increase SIZE of cells
- body builders skeletal muscle
hyperplasia
increased size of tissue due to increase NUMBER of cells
- smooth muscle
- endometrium
does pregnancy involve hypertrophy or hyperplasia
both
atrophy
decreased size of tissue due to increase NUMBER OR SIZE of cells
(joint term)
metaplasia
change in differentation of a cell from one fully differentaited cell type to a different fully differentiated cell type
ciliated columnar epithelium –> squamous (smokers)
squamous –> glandular columnar (barrets oesoph)
dysplasia
imprecise term - morphological changes in cells in progression to becoming cancer
- lose maturity
homeobox genes
a group of genes that direct developement . they each code for a different part of the body
which tissues divide more: old or young
young
telomeres
at end of chromosome
dont code for anything
get shorter as you get older, each time DNA replicates
name 3 pathologies of ageing
- senile dementia- - atrophy of brain
- dermal elastosis = wrinkles - collagen cross links protein in skin due to UVB light
- osteoporesis
- cataracts - the lens is foggy due to protein cross-linked due to UVB light
- deafness - cilia in the organ of Corti nonreplaceable
- sarcopenia -skeletal mass and strength declines (decreased testosterone and growth hormone)
carcinogenesis
normal cells to neoplastic cells (malignant) through multiple permanetnt genetic alterations/mutations on DNA
carcinogen classes
chemical (UVA ,UVB light) viral hormones (steroids, oestrogen) parasites mycotoxins (aflatoxin b1) ionizing, nonionizing( x rays ionising radiation) miscellaneous (asbestos, arsenic) host factors (race, gender, age, diet, smoking etc)
neoplasm contains
neoplastic cells
- normally monoclonal
stroma
- support mechanically + nutririon, growth factos, framework
- avascular until 2mm
how to classify a neoplasm
behavioural - benign/malignant/ bordeline
histogenic - cell of origin
behviousal classification of neoplasm
benign vs malignant
benign = localised (no metastases/invasion) non invasive- doesnt infiltrate surroundings, just pushes low mitotic activity, slow growth necrosis and ulceration = rare well defined border
innate vs adaptive immunity
innate
- non specific
- no lymphocytes (no memory). think non-lymphocyte leukocytes!
- present from birth
adaptive
- specific to antigen
- lymphocytes required
- aquired, learnt (memory)§
complements
=?
when activated, they?
which immune system are they part of
they are proteins
1 direct lysis (cell death by breaking cell membrane) 2 increase chemotaxis ( attract more wbc) 3 osponisation (coat/surrounding organism by binding to it, easier to phagocytose)
they are part of the innate immune system only
different T lymphocyte cells
Th - clocks antigen, cytokines released – activate macrophages. and natural killer cells. and activate B cells –> memory + plasma
Tc - target damaged/ infected cells –> apoptosis
Ts- inhibits Th to suppress immune response
poly/mononuclear lymphocytes
which are which!
poly
- neutrophil
- eosinophil
- basophil (-> mast cell)
mono
- monocyte (-> macrophage)
- T cell
- B cell
cytokines
made of
types
= proteins
interferons (IFN) - antiviral resistance in unaffected cells
interleukins (IL) - pro/anti inflammatory (secreted by leukocytes, act on leukocutes to divide, differentiate, secrete)
colony stimulating factors - direct division and differentation of bone marrow stem cells (–> blood cells)
tumour necrosis factors - mediate inflammation and cytoxic reactions
chemokines - direct leukocytes where to go
leukocytes vs lymphocytes
leukocyte = wbc
lymphocyte = type of leukocyte. they are mononuclear . they are either B or T
what happens in innate response
- coagulation
- increased blood supply
- increased vascular permeability
- endothelium –> sticky –> wbc recruited to tissue out of vessel
- these then kill pathogens and dead cells and neutrolise -toxins
- cells proliferate to repair damage
- clot removed
- normal fucntion reestablished
types of adaptive response
cell mediated – kill infected cell with intracellular , intrinsic pathogen (cellular response)
MHC1, CD8(Tc)
humoral – for an extracellular, extrinsic pathogen (antibody response)
MHC2, CD4 (Th)
what is a MHC?
types
which immune response to they relate to? how?
major histocompatibility complex- on cell surface, like receptor. it displays antigens
MHC1 is on all nucleated cells
MHC2 is on APC only
cell mediated adaptive response – intrinsic (intracellular) = MHC1
extrinsic (extracellular)= MHC2
they are on the outside of infected cells, and fit together with antigens on CD8/4 cells. this activates them to become T lymphocytes
what are CD4 and CD8 cells?
CD4 is precursor to Th cell (then goes on to activate macrophages and natural killer cells, and causes B cells to differenetiate)
CD8 is precursor to Tc cell (then goes on to kill infected phagocytes and damaged cells)
they are activated to become these by MHC on APC infected pathogen
CD4 activated by MHC2 (extrinsic-)
CD8 activated by MHC1 (intrinsic)
what are natural killer cells
the 3rd type of lymphocyte (not T or B) large granular lymphocyte they kill cells (virus and tumours) by secreting stuff - apoptosis also attract more immune cells found in spleen and tissues
Humoral (extra cellular) adaptive immune response
how is the pathogen presented
effect
naiive B lymphocyte encounters a pathogen that is complementary to its receptor
pathogen presented on MHC2
this activates CD4 –> Th (which then goes on to activate macrophages and natural killer cells, and causes B cells to differentiate)
and also activates B cell – clonal expansion and differentiation (to plasma/memory. cells)
antibodies role in adaptive immune response
how do they work
antibodies are specific to the encountered pathogen
1 opsonisation - surround to enhance phagocytosis (helps guide phagocytosis)
2 neutralise - bind to and neutralise bacteria + toxins
3 activate complements
types of pattern recognition receptor (PRR)
these can circulate freely (activate complements) and these are on immune cells:
nod like receptors (NLR) - for bacteria
rig like receptors (RLR) - for viruses
toll like receptors (TLR) - for lots of things
can initiate tissue repair?
what are lectins
what do lectins do
they are carb contating protein
they bind the proteins and lipids in microbe wall. this activates complements
toll like receptors (TLR) types
TLR4
- detects gram + bacteria
- regulates neutrophil level in the blood
- increase levels of cytokines so CD4 and CD8 activation to T cells
TLR5
– detects flagella
TLR3
– detects double-stranded RNA (virus)
TL7/8
– detects single stranded RNA (virus)
PRR and PAMP. which is where?
they stand for…
PRR is on immune cell - pattern recognition receptor
PAMP is on pathogen- pattern associated molecular patterns
what is a phagolysosome
this is created when lysosome vesicle binds with vacuole (phagocyte engulfed pathogen)
APC presents antigen how?
after phagocytosis, the antigen is presented on MHC
how are pathogens destroyed within the cell
oxygen dependant - ROI
- o2* –> h2o2 –> *OH (kills bacteria)
- NO increases vasodilation (wbc into area)
oxygen independent
- enzymes
- pH
- defensin protein
symptoms of allergic reaction
eczema
itching
red
bloating
vom
diarr
bronchoconstriction
excess mucous
atopy
inherited tendency to have exaggerated IgE response
– hayfever, asthma, eczema
gel and coombs classification of hypersensitivity reactions
- allergy, atopy, anaphylaxis
igE binds to mast cells so they release histamine
regulated by antihistamine (eosinophils)
2 ig G mediated
bound to cell surface antigens
transfusion reactions
drug/metablite combines with protein and body considers it foreign so creates antibodies
3 immune complexes = antibody + target
cause immune response –> tissue damage–> inflammation
SLE
hay barely compost droppings
4 T cell mediated, no ig
TB, contact dermatitis
granulomas
barriers to infection=
which immune response are they
physical (skin, cilia, mucous membranes)
physiological (cough,sneeze, vom, diar)
chemical (pH of stomach, vagina, skin, saliva, tears)
biological (nonpathogenic microbes compete for resources)
innate
how does penicillin work
halt cell wall synthesis
each antibody characteristics
IgM- beginning . large molecule (many connected)
IgG- v specific (target single epitopes). most abundant. single complex
IgE - allergies. single complex
IgA- on mucosal surface double complex
desensitisation to anaphylaxis
not possible
treatment for type 1 allergy reactions
cause/avoid exposure to allergen
antihistamine
steroid –> decrease inflammation
desensitisation
pros and cons of live attenuated organism vaccination
full natural response
one dose required only
b+t cell response
natural mutation - resistant
immunocomprimised patients cannot have
correct preparation vital
side effects of immune response- fever
pros and cons of inactivated organism vaccination
no risk of infection
full immune response triggered
easy storage
booster required (patient compliance)
only B cell repsponse, not T
immune response side effects eg fever