(Mine) Cellular Pathology

Question 1

Pathological stimuli brings about what changes?

Answer 1

Cell stress response.
Increased output of normal structural proteins and increased output of proteins with organising and protective functions.
Severe stimuli can lead to death.

Question 2

What is the function of chaperones?

Answer 2

Correct protein folding and can remove old or misfolded proteins through the ubiquitin-protease pathway.

Question 3

Explain the ubiquitin-protease pathway

Answer 3

1. Activated ubiquitin linked to damaged protein
2. Ubiquitinated protein recognised by protease
3. Abnormal protein destroyed
4. Ubiquitin recycled

Question 4

Define:
Atrophy
Hypertrophy
Involution
Hyperplasia
Metaplasia

Answer 4

Atrophy - reduction in size of cells
Hypertrophy - increase in size of cells
Involution - decrease in cell numbers
Hyperplasia - increase in cell numbers
Hyperplasia - stable change to another cell type

Question 5

How is atrophy/involution achieved?

Answer 5

By increased catabolism of structural proteins by autophagy.
- occurs due to lack of nutrients
- degradation of cytoplasmic components within lysosomes

Question 6

Examples of physiological and pathological atrophy/involution

Answer 6

Physiological - thyroid gland after pregnancy, skeletal muscle in old age
Pathological - disuse atrophy (immobilised limb), denervation atrophy (damage to axons), ischaemic atrophy (gradual reduction in blood supply)

Question 7

How would these cells adapt to deal with stress?
1. Bronchial columnar cells to cigarette smoke
2. Transitional cells of bladder to bladder stone
3. Fibrocollagenous tissue to abnormal use
4. Oesophageal squamous cells to gastric reflux

Answer 7

1. Squamous cells
2. Squamous cells
3. Bone deposition
4. Columnar cells

Metaplasia -> Dysplasia -> Tumour

Question 8

What are primary targets for damaging stimuli?

Answer 8

Cell membrane, mitochondria, protein synthesis/packaging machinery, cellular DNA

Question 9

How does cell death occur?

Answer 9

When damage threshold is passed, either:
- decrease in oxygen and nutrients
- by toxins e.g. cyanide

Question 10

What causes primary cell membrane and mitochondria injury?

Answer 10

Cell membrane- O2 free radicals, immune mediated damage, direct actions of bacterial toxins
Mitochondria - all types of cell injury

Question 11

What are the effects of a lack of ATP?

Answer 11

• Deficiency of oxygen leads to the failure of many metabolic processes that require energy
• Failure of Ca2+ pumps can cause severe damage
• Uncontrolled entry of Ca2+ into the cell
• Uncontrolled enzyme activation

Question 12

What are oxygen free radicals?

Answer 12

Metabolic intermediates of toxins and drugs. Chemical species with a single unpaired electron in an outer orbit - unstable and react with inorganic/organic material

Question 13

How do reactive oxygen metabolites cause cell damage?

Answer 13

• Increase permeability in the membrane lipid
• Critical protein damage e.g. Na/K ATPase pumps
• DNA fragmentation - possible role in malignancy
• O2 free radicals are scavenged by protective antioxidant systems

Question 14

What causes necrosis due to disintegration of cellular structure? Explain

Answer 14

Activation of lysosomal enzymes. Lysosomal enzymes contribute to the breakdown of organelles, leading to uncontrolled cellular lysis. Outcome is cell contents leak into extracellular space, triggering inflammation and damage to the surrounding tissue.

Question 15

Explain apoptosis necrosis (necroptosis)

Answer 15

Is the normal process. Removes unnecessary cells but can also remove damaged cells. Plasma membrane intact with no leakage of contents and no activation of inflammatory response.