Cell Injury and fate

Question 1

What are the types of cell injury?

Answer 1

• Lethal: produces cell death

- Sublethal: produces injury not amounting to cell death may be reversible or progress to cell death

Question 2

What are the causes of cell injury?

Answer 2

1. Oxygen deprivation
2. Chemical agents
3. Infectious agents
4. Immunological reactions
5. Genetic defects
6. Nutritional imbalances
7. Physical agents
   8 Aging

Question 3

What do the consequences of an injurious stimulus depend on?

Answer 3

1. Type of cell

2. Its status

Question 4

What four intracellular systems are particularly vulnerable?

Answer 4

1. Cell membrane integrity
2. ATP generation
3. Protein synthesis and
4. The integrity of the genetic apparatus

Question 5

What are important things to remember?

Answer 5

• The structural and biochemical components of a cell are so integrally related that multiple secondary effects rapidly occur
• Cellular function is lost before cell death occurs which in turn occurs before the morphological changes are seen

Question 6

What is atrophy?

Answer 6

-Shrinkage in the size of the cell (or organ) by the loss of cell substance

Question 7

What is hypertrophy?

Answer 7

• Increase in the size of cells and consequently an increase in the size of the organ
• Can be physiological or pathological
• It is caused either by increased functional demand or specific hormonal stimulation

Question 8

What is hyperplasia?

Answer 8

• Increase in the number of cells in an organ
• Can be physiological or pathological
• Physiological hyperplasia can be either hormonal or compensatory
• Pathological hyperplasia is usually die to excessive hormonal or growth factor stimulation

Question 9

What is metaplasia?

Answer 9

• A reversible change in which one adult cell type is replaced by another
• May be physiological / pathological

Question 10

What is dysplasia?

Answer 10

-Precancerous cells which show the genetic and cytological features or malignancy but not invading the underlying tissue

Question 11

What are the light microscopic changes associated with reversible injury?

Answer 11

• Fatty change, cellular swelling
• These are examples of degenerative changes e.g. changes associated with cell and tissue damage
• Alcoholic fatty change
• Cellular swelling- first manifestation of almost all forms of injury to cells

Question 12

What is necrosis and the different types?

Answer 12

-Confluent cell death associated with inflammation
Light microscopic changes associated with irreversible injury:
Coagulative necrosis
Liquefactive necrosis
Caseous necrosis
Fat necrosis

Question 13

What are the causes of apoptosis (programmed cell death)?

Answer 13

Embryogenesis
Deletion of auto-reactive T cells in the thymus
Hormone dependent physiological involution
Cell deletion in proliferating populations
Variety of mild injurious stimuli that cause irreparable DNA damage that, in turn triggers cell suicide pathways

Question 14

What is the difference between apoptosis and necrosis?

Answer 14

1. Apoptosis may be physiological
2. Apoptosis is an active energy dependent process
3. Not associated with inflammation

Question 15

What is necroptosis?

Answer 15

• Programmed cell death associated with inflammation
• Many causes e.g. viral infections
• Energy dependent process