Cell Injury And Fate

Question 1

What do lethal and sub lethal mean?

Answer 1

Lethal
Cell dearth

Sublethal
Produces injury not amounting to cell death Either reversible or leads to cell death

Question 2

What are some causes of cell Injury?

Answer 2

Oxygen deprivation 
Chemical agents
Infectious agents
Immunological agents
Genetic defects
Nutritional imbalances
Physical agents
Ageing

Question 3

What factors effect the cellular response to cell injury?

Answer 3

Type of injury
Duration
Severity

The type of cell
It’s status (proliferating, age)

Question 4

Which four intracellular systems are particularly vulnerable and bad to injure?

Answer 4

Cell membrane integrity
ATP generation
Protein synthesis
The integrity of genetic apparatus (DNA…)

Question 5

What is atrophy?

Answer 5

Shrinkage in the size of a cell or organ by the loss of cell substance

Question 6

What is hypertrophy?

Answer 6

Increase in the size of cells and consequently an increase in the size of an organ

Can be physiological (normal) or pathological (disease)

Can be cause by functional demand or hormones

Eg when athletes exercise their muscles get bigger

Question 7

What is hyperplasia?

Answer 7

Increase in cell number in an organ

Physiological or pathological

Physiological can be either hormonal or compensatory

Pathological is usually due to excessive hormonal or growth factor stimulation

Eg in pregnancy

Question 8

What is metaplasia?

Answer 8

A reversible change in which one adult cell type is replaced by another

Physiological or pathological

Eg in barrats oesophagus when usually squamous epithelial turns columnar due to acid reflux

Question 9

What is dysplasia?

Answer 9

Precancerous cells which show the genetic and cytological features of malignancy but do not invade the underlying tissue

Eg in late barrats oesophagus

Question 10

What are the light microscopic changes associated with reversible injury?

Answer 10

Fatty change
Eg in alcoholic fatty disease

Cellular swelling
Eg ballooning

Examples of degenerative changes

Question 11

What is necrosis?

Answer 11

Confluent cell death associated with inflammation

Question 12

What are four types of necrosis?

Answer 12

Coagulative necrosis

Liquefaction necrosis

Caseous necrosis

Fat necrosis

Question 13

What is coagulative necrosis?

Answer 13

Like frying an egg

Something just sets in place

Question 14

What is liquefaction necrosis

Answer 14

The cells/ organ becomes liquefied

Characteristic of brain necrosis

Question 15

What is caseous necrosis?

Answer 15

Cheesy

Seen in tuberculosis

Question 16

What is fat necrosis?

Answer 16

Seen in acute pancreatitis

Enzymes in the pancreas become activated early in the pancreas
Especially fat
Calcium deposits - free fatty acids bind to calcium ions

Question 17

What is apoptosis?

Answer 17

Programmed cell death
Death of individual cells

No inflammation around the cells

An active energy dependent process

Not associated with inflammation

Question 18

What is the difference between apoptosis and necrosis?

Answer 18

Necrosis involves a loss of membrane integrity so enzymes and stuff within the cell leaks out and whole sheets of cells die
There is also inflammation
Necrosis also damages healthy tissue around it

In apoptosis parts of the apoptotic cell break off but the cell membrane retains its integrity. These apoptotic bodies are eventually phagocytosed

Question 19

What are some causes of apoptosis?

Answer 19

Embryogenesis
Deletion of auto reactive T cells in the thymus
Hormone dependant physiological involution
Cell deletion in proliferating populations
Mild injurious stimuli that cause irreparable DNA damage, triggers cel suicide pathways

Physiological or pathological

Question 20

What is necroptosis?

Answer 20

Programmed cell death that also has inflammation

Seen in some viral infections