Pathology Flashcards
what is hyperplasia?
an increase in cell number, in response to an external response. Will regress on withdrawl of a stimulus
mechanism of hyperplasia?
- production of increased growth factor
- increased growth factor receptors
- genes encoding for growth factors and cell cycles switch on
what do areas in lymph nodes undergo in response to infection?
hyperplasia
what is hyperplastic and metaplastic tissue at risk of?
at risk of the development of cancer
what is hypertrophy?
an increase in cell size
what is atrophy?
reduction in cell size
mechanism for atrophy?
- protein degradation
- hormones can promote/oppose atrophy
what is metaplasia?
reversible change from one mature cell type to another mature cell type
in acute inflam, what mediates vascular vasodilation?
histamine and nitric oxide
steps of binding of neutrophils to endothelial cell wall
- binding due to CAMs on neutrophils and cell wall
- firstly lightly via selectins (on endothelial wall)
- tighter binding via ICAMs on endothelial cell with integrins on neutrophil
what increases selectin expression?
histamine and thrombin
what increases endothelial cell expression of VCAM and ICAM?
TNF and IL-1
clinical features of acute inflam?
rubor, dolor, calor, tumor, loss of function
what does a neutrophil look like?
polymorph granulocyte
what is suppuration?
pus formation
when is healing by organisation favoured?
when damage goes beyond the basement membrane
process of granulation tissue formation
- infiltration by capillaries and myofibroblasts
- collagen and smooth muscle cell deposit
what characterises chronic inflam?
presence of lymphocytes
what is a granuloma?
aggregate of epitheloid histiocytes
what is necrosis?
premature death of cells in living tissue, always pathological
what is coagulative necrosis and where is it seen?
cell death with preservation of the cell outline
seen in cardiac muscle
what is liquefactive necrosis and where is it seen?
cell death leaving behind a liquid viscous mass
seen in the brain
what is caseous necrosis and where is it seen?
granulomatous inflam with central necrosis
seen in TB
what is apoptosis?
programmed cell death in response to specific signals, requires energy
extrinsic pathway of apoptosis?
- mediated by TNF, Fas ligand (death receptors)
- bind to death receptors on the cell surface
intrinsic pathway of apoptosis?
- growth signals promote anti apoptotic molecules in the mitochondrial membrane
- bax and bak are pro apoptotic
- induce the release of cytochrome C
- this stimulates caspases
what is p53?
p53 can sense DNA damage, halt cell cycle and repair/induce apoptosis
what is dysplasia?
the enlargement of an organ or tissue by the proliferation of cells of an abnormal type, as a developmental disorder or an early stage in the development of cancer
causes of cellular ageing?
- oxidative stress
- accumulation of metabolism by products
what are telomeres?
chromosomes capped with TTAGGG repeats, stops degradation
