L3 cell injury & cell death

Question 1

biochemical mechanisms vulnerable to injury
(the 4 intracellular systems)

Answer 1

1. cell membranes
2. aerobic respiration
3. protein synthesis
4. genetic apparatus

Question 2

2 patterns of reversible cell injury seen under the light microscope

Answer 2

1. hydropic change/ cellular swelling/ vacuolar degeneration
   -Is the first manifestation of almost all forms of injury to cells.
   -appears whenever cells are incapable of maintaining ionic and fluid homeostasis
   -grossly the organ is heavy, inc. size, and pale
   -microscopically, clear vacuoles bc ER gets filled w/ fluid
2. fatty change
   -lipid vacuoles in cytoplasm
   -appears in hypoxic, toxic or metabolic injury
   -esp. in lipid metabolism related cells like heart or liver

Question 3

how are atp synthesis and cellular swelling related

Answer 3

if cell is injured, atp synthesis is low, therefore Na/K pump won’t function properly. leading to increased Na in the cell. which in turn will cause fluid to fill inside the cell due to osmosis.

Question 4

how to differentiate between fatty change and cellular swelling

Answer 4

-by the appearance of nucleus.
-in cellular swelling it’ll be in the center of the cell
-in fatty change it’ll be pushed to the periphery giving signet ring like appearance

Question 5

define necrosis, give details

Answer 5

-premature cell death
-or, cell death in living tissue
-due to external factors
-occurs in different forms
-ALWAYS pathological

Question 6

note on apoptosis

Answer 6

-programmed cell death
-from greek falling off
-can be physio or pathological
-referred to as cellular suicide bc of events taking place within the cell

Question 7

necrosis is associated with? and results from?

Answer 7

1.
-loss of membrane integrity
-leakage of intracellular components – local inflammation

2. -enzymatic digestion of the cell
   -denaturation of intracellular proteins

Question 8

nuclear changes of necrosis under microscope

Answer 8

1. pyknosis: small dark hyperpigmented nucleus
2. karyorrhexis: fragmented nucleus
3. karyolysis: no nucleus

Question 9

patterns of necrosis (6 types), based on tissue changes

Answer 9

1. coagulative
2. liquefactive
3. gangrenous
4. caseous
5. fibrinoid
6. enzymatic (fat)

Question 10

note on coagulative necrosis

Answer 10

-cause; ischemia in solid organs except brain
-eg: myocardial infarction
-gross; triangular subcapsular infarct with apex directed towards the organ’s capsule
-localized area of coagulative necrosis is called infarct
-microscopically cell retains the general feature, but details are lost

Question 11

gangrenous necrosis

Answer 11

-cause: coagulative necrosis w/ superadded infection (basically ischemia)
-e.g. diabetic foot
-dry gangrene (ischemic/necrotic area) turns into wet gangrene by liquefactive action of bacteria and the attracted leukocytes

Question 12

liquefactive necrosis

Answer 12

-cause, hypoxic cell death in cns
-bacterial and fungal infections