pathology formative 2 Flashcards
MI:what pattern of necrosis would you expect to find in the myocardium?
coagulative
how does coagulative necrosis appear? histological appearance
loss of cell detail but ghost outline of tissue architecture remains
coagulative necrosis found where
solid organ
what colour does coagulative necrosis appear in MI?
pale/white
occlusion of an end artery> cell death with very slight haemorrhage
why do cells swell during ischaemia?
loss of function of energy dependent membrane pump> sodium and water accumulate in cytoplasm
differences between necrosis and apoptosis
necrosis:
- sheets of cells affected
- associated inflammation
- cell swelling
- always pathological
- membrane breaks down
- diffuse/ random DNA cleavage
apoptosis:
- single cells affected
- no associated inflammation
- cell shrinkage
- pathological or physiological
- membrane intact
- internucleosomal DNA cleavage
why is swelling seen in an inflamed area?
chemical mediators are released> cause arterioles to dilate and endothelial cells to contract > spaces between endothelial cells
> dilation leads to inc hydrostatic pressure. within the capillaries and fluid is pushed out between the gaps into tissue spaces
> conc of protein within the tissue spaces is increased, osmotic pressure inc, pulls more fluid into the tissue spaces
functions of complement system
- kill bacteria by forming membrane attack complex which punches holes in membrane
- chemical mediators/ chemotaxis
- opsonisation
functions of macrophage
- phagocytosis
- secrete chemical mediators
- present antigens to immune system, initiating the immune response
- stimulate angiogensis
- induce fibrosis
- induce fever, acute phase reaction
what is a granuloma?
chronic inflammatory response
- collection of cells e.g. macrophages, giant cells, fibroblasts, lymphocytes
> surrounds and attempts to destroy difficult pathogens/particles
how do the 3 giant cells appear?
Langhans- nuclei around periphery
foreign body- nuclei arranged randomly
touton- nuclei arranged in a ring towards cell centre
what type of necrosis does Tuberculosis show?
caseous
> central zone of necrosis
amorphous, structureless, eosinophilic, granular
conditions in which granulomas are commonly seen?
syphilis leprosy fungal infection crohns disease chronic granulomatous disease TB sarcoidosis
eosinophils raised when?
allergic reaction
infection with large parasite
some tumours e.g. Hodgkins lymphoma
why can’t myocardium regenerate?
myocytes are permanent cells and no stem cells are present
which tissues must always heal with a scar?
skeletal muscle
neural tissue
cardiac
principle cellular constituents of granulation tissue
fibroblasts
endothelial cells/capillaries
local factors that can impair wound healing
poor blood supply local infection presence of foreign bods large amount of necrotic tissue poor surgical technique large size of wound
describe route of thrombi-embolism from leg veins to lungs
deep veins of calf iliac veins inferior vena cava right atrium right ventricle pulmonary artery
diff between thrombosis and clotting
thrombosis
- pathological
- inappropriate formation within a vessel
clotting
- physiological
- controls bleeding when vessels are severed
- occurs outside vessels
Virchows triad
Abnormal flow
Abnormal blood constituents
Abnormal vessel wall
mechanisms of death with PE
respiratory compromise> non perfused but ventilated area of lung> hypoxaemia
haemodynamic compromise- incr resistance to pulmonary blood flow due to obstruction of pulmonary vessels > Right sided heart failure
complications of abdominal aortic aneurysm
- rupture and haemorrhage
- thromboembolism to legs causing acute ischaemia
- aortic occlusion or rupture
xanthelasma caused from which condition?
its weird blobs on their eyes
- hyperlipidaemia
- hypercholesterolaemia
