Cellular Adaptations and Damage

Question 1

Define the terms dysplasia and neoplasia

Answer 1

Dysplasia = pre-malignant condition, increased cell growth, cellular atypic, altered differentiation. Can range from mild to severe, sites = cervix, bladder, stomach/oesophagus

Neoplasia = abnormal growth of cells which persists after initiating stimulus has been removed. Can be benign or malignant.

Question 2

What are cellular adaptations?

Answer 2

Reversible changes in cells in response to changes in the environment - reflects an attempt to preserve cell vitality and meet change in conditions (physiological or pathological).

It involves changes in: cell number, cell size and cell type

Question 3

Explain the patterns of cellular adaptation seen secondary to non-lethal cell damage

Answer 3

Increase cell size
Increase cell number
Increase both

Question 4

Outline the causes and patterns of cellular response to noxious stimuli

Answer 4

Causes of cell injury = oxygen deprivation, physical agents, chemical + drugs, infectious agents, immune reactions, genetic derangements, nutritional imbalances

Question 5

Outline the mechanisms and targets of cell damage

Answer 5

1. Depletion of ATP - reduced synthesis or depletion as use too quickly. If high glycolytic activity of cell then impact will range.
2. Mitochondrial damage - ATP depletion, ROS generation, formation of pores in membrane leading to loss of organelle microenvironment + function, protein release into cytosol
3. Loss of calcium homeostasis - influx activates enzymes
4. Oxidative stress - imbalance in generation and removal causes cell injury

Question 6

Describe the features of apoptosis and necrosis

Answer 6

Necrosis = unprogrammed cell death, pathologic, enzymatic cell digestions, cell contents leak out. Different types: coagulative, liquefactive, caseous, gangrenous, fat, fibrinoid.

Apoptosis = programmed cell death, pathologic/physiologic, internally controlled, nuclear dissolution.

Features = imbalance between pro-apoptotic and anti-apoptotic molecules in the cell. Activation of caspases, DNA + protein breakdown, membrane alterations and recognition by phagocytes

Question 7

Define and Describe physiological and pathological examples of metaplasia

Answer 7

Metaplasia = reversible change from one adult cell type to another adult cell type (adaptive response)

PHYSIOLOGICAL = normal growth + development e.g. cervix

PATHOLOGICAL = abnormal environment causes adaptive response e.g. Barrett’s

Question 8

What disorders are associated with dysregulated apoptosis?

Answer 8

Defective apoptosis + increased survival = neoplastic + autoimmune cells

Defective apoptosis + decreased survival = ischaemic injury + death of virus infected cells