Reversible And Irreversible

Question 1

Reversible plasma membrane alteration

Answer 1

blebs, loss of microvilli, loosing of intercellular attachment

Question 2

Reversible Mitochondrial alteration

Answer 2

earliest manifestation of sublethal injury

swelling, appearance of phospholipid rich amorphous densities

Question 3

Reversible dilation of endoplasmic reticulum

Answer 3

loss of the ribosomes

Question 4

Reversible nuclear alteration

Answer 4

clumping of nuclear chromatin

Question 5

Two patterns of morphologic change can be recognized under the light microscope

Answer 5

Cellular swelling

Fatty change

Question 6

Cell swelling

Answer 6

Called hydropic changes or vacuolar degeneration
universal to all cell types
loss of ionic and fluid homoeostasis
cells show clear vacuoles in the cytoplasm
distended and pinched-off segments of ER

Question 7

Fatty changes

Answer 7

Specific to cells dealing with fat metabolism, liver and heart
Lipid vacuoles in the cytoplasm

Question 8

gross features of reversible injury:

Answer 8

increase in the weight of the organ

pallor of the organ

Question 9

excessive damage to all membranes, cytosolic and organelles

Answer 9

Irreversible injury (lethal)

Question 10

a potential mediator of irreversible cell death.

Answer 10

Calcium is a potential mediator of irreversible cell death. Increase intracellular Ca content from the extracellular compartments, with activation of the different enzymes

Question 11

With the low pH,……… are activated.

Answer 11

Leakage of digestive enzymes from lysosomes.
With the low pH, hydrolases are activated. They begin to digest the cell components.

Autolysis: if the cells are digested by their own enzymes
Heterolysis: if the cells are digested by lysosomes from other cells

Question 12

These processes require hours to develop, and so there are no detectable changes in cells if, e.g., a myocardial infarct causes sudden death.

Answer 12

Irreversible functional changes (which precede any morphologic change)

Question 13

most necrotic cells and their debris disappear by

Answer 13

a combined process of extracellular enzyme digestion and leukocyte phagocytosis.

Question 14

If necrotic cells and cellular debris are not promptly eliminated

Answer 14

They will attract calcium salts and other minerals and undergo dystrophic calcification

Question 15

Two phenomena characterize irreversibility

Answer 15

Inability to reverse mitochondrial dysfunction
Development of severe membrane damage
this is the vital step to which no return

Question 16

Cell membrane damage:

Answer 16

Progressive loss of membrane phospholipids.
By activation of phospholipases by Ca, and decrease synthesis of proteins
Cytoskeletal abnormalities.
Loss of the filaments between the cytoplasm and the cell membrane. So the cell membrane becomes loose and susceptible to rupture.
Toxic oxygen radicals.
This leads to peroxidation of the membranes.
Lipid breakdown products.
These act as detergents on the membranes.

Question 17

mitochondrial dysfunction

Answer 17

One of the earliest manifestations of irreversible cell injury is the vacuolization of the mitochondria, and the accumulation of amorphous, calcium-rich densities in mitochondrial matrix
Affect the oxidative Phosphorylation, decrease ATP

Question 18

The morphological correlations of irreversible cell injury

the sequence of morphological changes that follows cell death in living tissue

the sequence of morphological changes that follows cell death in living tissue

Answer 18

Necrosis

Question 19

1- enzymatic digestion of the cell

 * by lysosomal enzymes:
    - autolysis.                          - heterolysis.

Answer 19

=>Leakage of proteins and cellular constituents e.g:
Cardiac muscle: creatine kinase & troponins.
Liver: alkaline phosphatase

Question 20

Ultrastructural morphological changes: Necrosis

Answer 20

Defects in cell membrane
Mitochondrial swelling and large densities
Swelling of the ER and detachment of ribosomes
Appearance of myelin figures
Rupture of lysosomes

Question 21

Necrosis: Light microscopic features

Answer 21

Changes in the cytoplasm in Necrosis:
acidophilia of the cytoplasm (pink staining)
binding of eosins to denatured proteins
loss of basophilia from the loss of RNA
glassy cytoplasm: loss of glycogen
vacuolated cytoplasm: degeneration of organelles
calcification of cells
Changes in the nucleus in Necrosis:
Pyknosis: increased basophilia due to shrinkage of the nucleus
Karyorrhexis: fragmentation of the pyknotic nucleus by nucleases
Karyolysis: loss of the basophilia of the chromatin, secondary to DNAase activity.
1-2 days following death, the nucleus disappears completely

Question 22

nucleus disappears completely

Answer 22

1-2 days following death