Flashcards
Cell degeneration and necrosis
Cards in this deck (61)
- 1Name the 5 changes in cell growth/adaptationshypertrophy
hyperplasia
atrophy
metaplasia
neoplasia - 2What are the 2 types of cellular degenerationcellular swelling
fatty change - 3What is cellular swellingmildest, earliest detectable degenerative change
- 4How does cellular swelling appear macroscopicallymay be no visible change
or
tissue may be paler than normal and may bulge on sectioning - 5How does cellular swelling appear microscopicallyindividual cells will be swollen with pale cytoplasm or small clear vacuoles due to distension of the ER "hydropic degeneration"
- 6What is the electron and light microscopic appearance of cellular swellingexcess fluid accumulates in the ER
ER swells and eventually fragments, leaving a fluid filled vacuole - 7How does fatty change appear macroscopicallyswollen, pale, friable, greasy texture
- 8How does fatty change appear microscopicallyaccumulation of variably sized round vacuoles
nuclei pushed to the edge of the cell - 9Where is fatty change commonly seenparenchyma of the liver, kidney and heart
- 10What is the term for fatty change in the liver and what distribution can occurheptic lipidosis
diffuse, zonal, focal - 11How can fatty change be identifiedH&E
Sudan black
Oil Red O - 12Why are sections frozen prior to stainingfat dissolves in alcohols used in processing of sections to make slides leaving empty vacuoles
- 13What are the 5 causes of fatty change within the liver1 - excess delivery of free fatty acids/TG
2 - impaired metabolism
3 - impaired synthesis of apoprotein
4 - impaired production and release of lipoprotein
5 - decreased oxidation of fatty acids - 14What are the causes of hypoxia associated with fatty changeanaemia
chronic passive congestion
ischaemia
toxins - 15What are the causes of fatty change within the bodystarvation
overeating
metabolic disease
Diabetes - 16How does starvation cause fatty changemobilisation of fat reserves, liver is unable to metabolise all released free fatty acids so they are stored
- 17How does overeating cause fatty changeobesity where the dietary intake is greater than the energy expenditure. Fat is stored by the liver before movement to fat stores
- 18How does metabolic disease lead to fatty changederanged carbohydrate metabolism - glucose not available for uptake into the tissues.
Alternative energy sources are used - 19How does Diabetes mellitus lead to fatty changedeficiency of insulin which is required for cellular glucose utilisation.
Cells can't use glucose so demand for alternative energy leads to fat mobilisation - 20T/F Cellular swelling and fatty change are reversibleTrue
- 21What processes occur during necrosis- irreversible cell injury -> cell death
- loss of membrane integrity
- evokes an inflammatory reaction - 22What are the 3 main causes of necrosisloss of blood supply - tissue needs blood supply to remain alive
living agents - bacteria, viruses, fungi, parasites
non-living agents - chemicals or physical injuries - 23How does loss of blood supply cause necrosishypoxia - reduced blood supply
ischaemia - loss of blood supply
infarction - necrosis of a portion of tissue due to an interruption of blood supply to that portion - 24How does tissue ischaemia occur- compression of blood vessel from outside
- narrowing of vessel lumen due to mural wall thickening
- blockage of vessel lumen - 25Describe the process of intestinal torsion1 - venous outflow impeded
2 - organ swells due to congestion
3 - swelling impedes arterial flow
4 - arterial flow stops
5 - tissue undergoes ischaemic necrosis
6 - intestinal blood barrier compromised
7 - bacterial toxins absorbed - death or intestine friable, prone to rupture - 26What processes occur following narrowing of the vessel lumenarteriosclerosis - hardening/ thickening of the artery. May occur in hypertension
atherosclerosis - cholesterol deposits, inducing an inflammatory reaction. Rare in animals - 27What processes occur following blockage of the lumenthrombosis and embolism
- 28Name physical agents that can cause necrosisburns, cold, frostbite, x rays, pressure, pinching/crushing of tissue
- 29Name chemical agents that can cause necrosisdirectly caustic or corrosive in action or exert their effects when absorbed and metabolised to a more toxic substance
- 30What are the gross and histological features of necrotic tissue- colour change in the tissue - dead tissue tends to be paler
- consistency of the tissue - appearance of the centre of the necrotic lesion will vary depending on the agent responsible/tissue it is acting on - 31What are the 3 types of necrosis - gross description1 - coagulative - remains firm
2 - liquefactive - becomes liquid
3 - caseous - a mixture of the two - cottage cheese like. - 32How does coagulative necrosis appear grossly?firm and dry on cut surface
still resembles in outline the adjacent viable tissue - 33How does coagulative necrosis appear microscopically- tissue architecture is preserved
- cells may appear larger and their outline may be lost
- cytoplasm appears larger and their outline may be lost
- cytoplasm appears structureless and homogenous
- important nuclear changes - 34What are the causes of coagulative necrosis- bacterial toxins
- infarction
- some foci of viral replication e.g. herpesvirus - 35What are the 2 types of liquefactive necrosismalacia - CNS
abscesses - anywhere in the body - 36What is the cause of cerebrocortical necrosis in ruminantsthiamine (Vit B) deficiency
- 37What are abscesses-pyogenic organisms
- bacteria cause necrosis and attract vast numbers of neutrophils
- dying neutrophils release proteolytic enzymes which digest necrotic tissue
- pus = dead and dying neutrophils, dead tissue and organisms - 38What are the 3 features of liquefactive necrosis that appear microscopically- necrotic area
- pyogenic membrane
- fibrous tissue capsule - 39What is the necrotic area composed of- varying stages of degeneration and death of neutrophils
- homogenous structureless mixture of remnants staining faintly bluish - 40What is the pyogenic membrane and what is it composed of- reddish membrane on inner surface of the capsule
- composed of blood vessels responsible for transporting the vast number of neutrophils to the lesion - 41What is the fibrous tissue capsule- part of the host inflammatory reaction
- walls off the irritant - 42How does caseous necrosis appear grossly- cheese like necrosis
- white to grey to yellow in colour
- varying consistency
- mixture of coagulative and liquefactive necrosis - 43What are the causes of caseous necrosiscaused by specific organisms e.g. mycobacteria or fungi
- 44Mycobacterium tuberculosis is an example of which type of necrosis and which stain confirms its presenceCaseous
Zhiel-Neelsen - 45How does mycobacterium tuberculosis appear microscopically- complete loss of architecture
- purplish necrotic material - due to random mixing of nuclear/cytoplasmic components that stain with H&E
- large proportion of necrotic tissue is composed of macrophages - 46What is dystrophic calcification and which species is it commonly found in- calcium deposits makes the tissue more inert
- common in cattle and sheep - 47How does dystrophic calcification appear grossly- calcium granules can be palpated
- knife grates on sectioning
- chalk white in colour
- yellow-green tinge due to eosinophils - 48How does dystrophic calcification appear microscopically and what stain is used for identification- dark blue colour
- shattering of tissue - microtome mark
- stains black with Von Kossa stain - 49How does fat necrosis appear grossly- area of focal opacity
- v hard consistency - 50What is the pathogenesis of fat necrosis- adipocytes die
- fat broken down into fatty acids
- FA combine with salts e.g. Ca2+, Na+, K+
- soaps are formed - provokes inflammatory response
- foci remain indefinitely and calcify - 51Which condition is fat necrosis commonly seen in and whypancreatitis
lipase release from pancreas - 52What are the 3 types of fat necrosis1 - enzymatic
2 - traumatic
3 - diet related - 53What is enzymatic necrosis- release of pancreatic enzymes especially lipase from a damaged pancreas
- goes into adjacent mesenteric fat - 54What is traumatic necrosis- subcut tissue following trauma
- especially brisket of recumbent animals due to prolonged pressure - 55What is diet related necrosis- rarely in cats associated with diets lacking antioxidants e.g. vit E
- 56What are the nuclear changes in necrosispyknosis
karyorrhexis
karyolysis - 57What is pyknosis- normal nuclear structure is replaced by a very dense, hazily staining, smaller angular mass of chromatin
- 58What is karyorrhexisnucleus has broken up into several dense pieces
- 59What is karyolysisnuclear staining with haemotoxylin becomes faint and ghost outline of nucleus remains
- 60What are the cytoplasmic changes that appear in necrosissometimes stains brighter pink
- 61What are the mitochondrial changes that appear in necrosisdense bodies
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- BSc Pathology Flashcards on Cell degeneration and necrosis, created by Teresa Richards on 04/10/2016.
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