Definitions Flashcards
Oncogene
Any protein or gene involved in regulating the cellular response to signalling and driving the cell into cell cycle. When something goes wrong it has the oncogene phenotype of confering to the cell the ability to grow in soft agar and or form tumours in athymic mice
Contact inhibition
Cells cease to divide when they hit solid or another cell
Antioncogene
Gene or protein involved in stopping the cell going into cell cycle/regulating cell division/growth
Hyperplasia
Increase in cell number in the tissue or organ
Often found with hypertrophy
Pathogenesis: tumour
Physiological: pregnancy
Can be diffuse or nodular
Nodular spleen/liver hyperplasia in old dogs common with ni conseq
Hypertrophy
Increase in cell size (results in increased organ size) mainly in m cells
Often found with hyperplasia
e.g ventricular muscle wall size increase
Metaplasia
One adult cell type replaces another adult cell type. Often reserve/stem cells differentiate along a different less specialised line
Often precurse neoplasia
eg squamous metaplasia caused by chronic irritation (columnar epi to squamous epi)
Dysplasia
Abnormal cell size, shape and organisation
Often precurse neoplasia
Atrophy
Loss of cell substance - shrinkage due to disuse, degeneration, blood or nerve supply loss, inadequate nutrition
NOT DEAD YET shrink to survive
Physiological: thymus, mammary post lactation
Oncotic necrosis
Death by swelling
Irreversible
Pyknosis
Small shrunken dark dense nucleus
Karyorrhexis
Fragmented nucleus
Karyolysis
Nucleus lyses or disappears
Fat necrosis
Pancreatic enzymes liquefy adjacent fat cells specifically. FAs and Ca2+ creates chalky material. Can be traumatic necrosis (working dog injury - localised)
Gangrenous necrosis
Can follow coagulative necrosis
Moist/gas: saprophytes invade dead tissue
Dry: mummification
Liquefactive necrosis
Cavities filled with liquid debris (tissue, dead bacteria, dead/dying cells) often bacterially caused.
Abcesses, also found in CNS due to sudden hypoxic damage as little fibrous network to support the cells
Caseous necrosis
Cheese-like friable look, chronic lesion, may develop dystrophic calcification
Coagulative necrosis
Very quick, shut down
No immediate disintegration, outline preserved, ghost tissue, delayed proteolysis, acute
Hypoxic death characteristic in all except brain
Eg renal infarct
Infarct
Localised ishaematic necrosis
Ischaemia
Perfusion lowered relative to tissue/cell metabolic needs
Apoptosis
Organised, neat cell death
A form of PCD
no inflam, altered surface material markers to promote phagocytosis
Atrophy
Labile cells
Continuously divide and regenerate from stem cell population
Stopping dividing is dangerous
Only replicate and replace and repair if there is an appropriate CT scaffold
Can scar or regenerate
Eg BM and skin
Stable cells
Quiescent Replicate if needed Only replicate and replace and repair if there is an appropriate CT scaffold Can scar or regenerate Eg liver gland cells
Permanent
In G0
No replication
Cardiac m cells
Neuronal cell bodies
Cachexia
Weight loss and debility during cancer
Muscle and fat are lost and feeding up doesn’t help (in starvation preferentially fat, and feeding up helps)
Unknown exact cause: thought to be cytokines
