Cell Injury

Question 1

Is cell injury reversible

Answer 1

initially it is reversible;
then becomes irreversible.
if injury is severe from onset, cell undergoes apoptosis

Question 2

2 ways cell death occurs

Answer 2

apoptosis

necrosis

Question 3

causes of cell injury (8)

Answer 3

1. oxygen deprivation
2. nutritional imbalances
3. infectious agents
4. immune response
5. genetic defects
6. chemical agents
7. physical agents
8. AGING

Question 4

hypoxia

Answer 4

deficiency of oxygen

Question 5

ischaemia

Answer 5

inadequate blood flow to tissues . leads to hypoxia.

Question 6

ischaemia - causes

Answer 6

1. narrowing of blood vessel
2. blockage of bv
3. decresed blood pressure

Question 7

effects of ischaemia

Answer 7

oxygen deficiency
glucose deficiency
nutrient deficiency

Question 8

causes of hypoxia (4)

Answer 8

1. lung disease
2. ischaemia
3. low O2 concn (high altitudes)
4. reduced oxygen carrying capacity of blood (anaemia/ CO poisoning)

Question 9

when are gross morphological changes visible in a cell

Answer 9

long after cell has died

Question 10

sequence of events in cell death?

Answer 10

1. decreasing cell function
2. cell death ensues
3. ultrastructural changes
4. light microscopic changes
5. gross morphological changes

Question 11

morphological changes of reversibly injured cell detectable by light microscope

Answer 11

1. swelling
2. vacuolar degeneration OR hydropic change (accumulation of water intracellularly)
3. fatty change

Question 12

morphological changes of reversibly injured cell detectable by electron microscope (ultrastructurally)

Answer 12

1. nuclear: clumping of CHROMATIN
2. dilation of ER
3. swelling of mitochondria & appearance of phospholipid-rich densities & calcification
4. PM blebbing;
5. loosening of intercellular attachments
6. distortion of microvilli/blunting

Question 13

define the fatty change in reversible injury

Answer 13

abnormal build up of triglycerides within parenchymal cells

Question 14

causes for fatty change

Answer 14

1. alcohol / toxins
2. protein malnutrition
3. diabetes
4. obesity.
5. hypoxia

Question 15

cells affected by fatty change

Answer 15

those dependent on fat metabolism:
-myocardial cells
-hepatocytes
skeletal muscle
kidney and others

Question 16

what’s different about necrotic, H&E stained cells

Answer 16

they have increased eosinophilia (redness) due to loss of RNA and less proteins (denatured proteins)

Question 17

what can ultimately happen to necrotic cells

Answer 17

become calcified (dystrophic calcification)

Question 18

ultrastructural changes in cell necrosis

Answer 18

1. discontinuities in membrane of organelles and plasma membrane
2. dilation of mitochondria
3. disruption of lysosomes
4. nuclear dissolution
5. intracytoplasmic myelin figures

Question 19

nuclear changes in necrotic cells

Answer 19

dissolution of basophilic chromatin (KARYOLYSIS)
PYKNOSIS - nuclear shrinkage +increased basophilia
KARYorrHEXIS - fragmentation pyknotic nucleus

Question 20

why all these nuclear changes

Answer 20

due to breakdown of DNA and chromatin

Question 21

types of tissue necrosis (patterns) (6)

Answer 21

1. fibrinoid necrosis
2. fat necrosis
3. coagulative necrosis
4. liquefactive necrosis
5. gangrenous necrosis
6. caseous necrosis

Question 22

coagulative necrosis facts

Answer 22

basic tissue architecture preserved;

but firm texture

Question 23

infarction

Answer 23

term can be used to describe necrosis of all organs/tissues EXCEPT brain

Question 24

liquefactive necrosis

Answer 24

digestion of dead cells = transformation into liquid viscous mass
typical of bacterial infections (pus) = abscesses

Question 25

gangrenous necrosis

Answer 25

caused by acute ischaemia
may/not have infection present too
coagulative&often superimposed liquefactive necrosis

Question 26

caseous necrosis

Answer 26

cheese-like, friable white appearance. encountered mainly w TB

Question 27

with which necrosis pattern is granuloma often seen

Answer 27

caseous necrosis

Question 28

granuloma?

Answer 28

gathering of cell debris and fragmented cells bordered by inflammatory cells

Question 29

fat necrosis

Answer 29

saponification of fat - whitish/chalky material produced.

Question 30

examples of fat necrosis

Answer 30

breast - following trauma

acute pancreatitis

Question 31

fibrinoid necrosis

Answer 31

deposition of fibrin in the walls of blood vessels

Question 32

how to detect tissue necrosis

Answer 32

detect biochemical markers (enzymes and other proteins) in blood and urine

Question 33

biochemical markers of tissue necrosis?

Answer 33

substances released from necrotic cells

Question 34

Apoptosis

Answer 34

programmed cell death

activation of internal self-destruction programme

Question 35

is apoptosis only pathological?

Answer 35

it’s necessary for normal function also

Question 36

when apoptosis

Answer 36

injury beyond repair

Question 37

morphology of apoptosis

Answer 37

• cell membrane stays intact

- fragmentation into apoptotic bodies

Question 38

fate of apoptotic bodies

Answer 38

phagocytosed by macrophages and neighbouring cells

Question 39

pro of apoptosis

Answer 39

minimal disruption to neighbouring cells

Question 40

compare cell size in APOPTOSIS v NECROSIS

Answer 40

A - reduced (shrinkage)

N - swelling

Question 41

compare nucleus

Answer 41

A - fragmentation

N - Pyknosis –> karyorrhexis –> Karyolysis (?)

Question 42

compare PM

Answer 42

A - intact

N- disrupted

Question 43

compare Adjacent inflammation

Answer 43

A - no

N - frequent

Question 44

compare Physiologic or pathologic

Answer 44

A - can be either

N - always PATHOLOGIC