cell injury

Question 1

5 cellular adaptations to injury

Answer 1

atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia

Question 2

define atrophy

Answer 2

shrinkage in size of cell organ because of loss of cell substance (cell number and size both decrease)

Question 3

example of atrophy

Answer 3

dementia

Question 4

what is atrophy caused by

Answer 4

malnutrition, poor circulation, poor exercise, loss of nerve supply to organ

Question 5

define hypertrophy

Answer 5

increase in size of cells, increasing size of organ

Question 6

example of physiological hypertophy

Answer 6

pregnancy

Question 7

example of pathological hypertrophy

Answer 7

blood pressure

Question 8

what is hypertrophy caused by

Answer 8

increased functional demand or hormonal stimulation

Question 9

define hyperplasia

Answer 9

increase in number of cells, increasing size of organ

Question 10

example of physiological hyperplasia

Answer 10

menstrual cycle

Question 11

example of pathological hyperplasia

Answer 11

excess TSH causing thyroid cancer

Question 12

causes of physiological hyperplasia

Answer 12

hormonal or compensatory

Question 13

causes of pathological hyperplasia

Answer 13

excessive hormonal or growth factor stimulation

Question 14

define metaplasia

Answer 14

reversible change where adult cell type replaced by another (e.g. effect of smoking)

Question 15

examples of physiolocial metaplasia

Answer 15

in cervix, columnar epithelia to squamous and back; in Barrett’s oesophagus, squamous epithelia to columnar and back with acid reflux

Question 16

define dysplasia

Answer 16

presence of precancerous cells which show genetic and cytological features of malignancy (e.g. high nuclear:cytoplasmic ratio) but don’t invade underlying tissue

Question 17

example of dysplasia

Answer 17

in some cases Barrett’s oesophagus

Question 18

necrosis definition

Answer 18

confluent (many adjacent cells) cell death associated with inflammation

Question 19

when does necrosis occur

Answer 19

when insufficient ATP is present

Question 20

necrosis pathway

Answer 20

damage to cell membrane → fluid released (incl. enzymes etc.) → attraction of neutrophils → inflammatory reaction

Question 21

types of necrosis

Answer 21

coagulative, liquefactive, caseous, fat

Question 22

define coagulative necrosis

Answer 22

cells are dead but can be seen and identified as particular cell type as everything keeps its shape

Question 23

example of coagulative necrosis

Answer 23

myocardial infarct

Question 24

define liquefactive necrosis

Answer 24

where the cell dies, becomes a liquid and is entirely drained out

Question 25

where is coagulative necrosis specific to

Answer 25

brain

Question 26

define causeous necrosis

Answer 26

when cut, it oozes and appears creamy and “cheesy”

Question 27

examples of causeous necrosis

Answer 27

pulmonary TB

Question 28

what is causeous necrosis associated with

Answer 28

granulomas (type of chronic inflammation)

Question 29

define fat necrosis

Answer 29

fat salts produced, forming deposits

Question 30

inflammation of pancreas as example of fat necrosis

Answer 30

increased lipase production → acute pancreatisis → triglycerides broken down to glycerol and fatty acids → fatty acids bind to calcium in EC fluid → calcium fat salts produced, forming deposits

Question 31

define apoptosis

Answer 31

programmed single cell death requiring ATP, with no inflammation

Question 32

DNA and p53 as cause of apoptosis

Answer 32

DNA irreversibly damaged; cell becomes “stuck” as the p53 tumour suppressor gene prevents proliferation

Question 33

why is apoptosis preffered

Answer 33

an inflammatory reaction to DNA would damage other healthy cells around it

Question 34

process of apoptosis

Answer 34

parts of cell bud off → cell membrane never ruptures, instead blebs → contents of cells kept in vesicles → vesicles phagocytosed by macrophages

Question 35

reasons for apoptosis

Answer 35

embryogenesis, deletion of auto-reactive T cells in thymus, hormone-dependent physiological involution (e.g. menstrual cycle), cell deletion in proliferating populations, variety of mild injurious stimuli causing irrepairable DNA damage

Question 36

necrosis vs. apoptosis

Answer 36

apoptosis may be physiological, necrosis is always pathological, apoptosis is an active energy-dependent process, apoptosis is not associated with inflammation

Question 37

define necroptosis

Answer 37

programmed cell death which is energy dependent but associated with inflammation (so halfway house); many causes e.g. viral infections