1 Pathological processes I

Question 1

Define hypertrophy.

Answer 1

The enlargement of an organ due to enlargement of its constituent cells.
Number of cells remains the same, size of each cell increases.

Question 2

Define hyperplasia.

Answer 2

An increase in the number of cells within a tissue or organ.

Question 3

What type of organ normally exhibits hypertrophy?

Answer 3

An organ with an inability or decreased capacity to increase its number of cells.

Question 4

Give an example of an organ with a limited ability to increase its number of cells.

Answer 4

The heart: myocytes have a limited ability to divide and icnrease in number.
Exercise leads to “stretch” of individual cells and release of adrenergic hormones and growth factors.
E.g. athletes may develop hypertrophy of the heart to accomodate for exercise levels.

Question 5

What are the 3 main causes of hypertrophy?

Answer 5

• Increased demand for work or increased stimulus for the function which that organ provides (e.g. exercise)
• Pathophysiology e.g. hypertension leading to left ventricular hypertrophy
• Drugs: phenytoin is an anti-convulsive drug which can cause gingival hypertrophy

Question 6

Give an example of hyperplasia in the liver.

Answer 6

Partial resection of the liver causes all remaining hepatocytes to proliferate and increase in number

Question 7

Give an example of hyperplasia in the female reproductive system.

Answer 7

Pituitary hormones and oestrogen can cause endometrial hyperplasia.

Question 8

Give an example of hyperplasia in the skin.

Answer 8

Proliferation of fibroblasts and endothelial cells in response to injury.

Question 9

Give an example of hyperplasia involved in HPV infection.

Answer 9

Virus infects eipdermal cell and replicates, producing a cold sore.

Question 10

Give an example of hyperplasia in the prostate.

Answer 10

The prostate gland enlarges with age.

Question 11

Which cellular responses are involved in pregnancy?

Answer 11

Cells in the uterus undergo hyperplasia and hypertrophy to accomodate the foetus.

Question 12

Define aplasia.

Answer 12

Failure for a body part/limb/organ to develop at all.

Question 13

Define hypoplasia.

Answer 13

Underdevelopment of a body part/limb/organ.

Question 14

Define atrophy.

Answer 14

Shrinkage in size of a cell, tissue or organ.

Question 15

What are the 4 forms of atrophy?

Answer 15

• Disuse
• Nutritional
• Pressure
• Denervation

Question 16

Describe disuse atrophy.

Answer 16

• Decreased demand for usage creates an imbalance between protein synthesis and protein degradation
• Regulated by signalling pathways induced by mechanical stress, physical activity, nutrient supply and GFs
• E.g. tooth loss, reduced mastication, reduced mechanical stress = alveolar bone atrophy

Question 17

Describe nutritional atrophy.

Answer 17

• Inadequate supply of nutrients
• Induces catabolic state (breakdown of tissues) to use cell protein for energy
• E.g. cachexia associated with cancer: TNF suppresses appetite thus inducing nutritional atrophy

Question 18

Describe pressure atrophy.

Answer 18

• Decreased size due to pressure
• Pressure created by expanding mass e.g. benign tumour, cyst
• Compresses BVs supplying tissue leads to lack of nutrients and oxygen

Question 19

Describe denervation atrophy.

Answer 19

• Absence of connection of functioning neural supply
• Induces breakdown of contractile proteins, causes atrophy
• E.g. motor neurone disease

Question 20

Define metaplasia.

Answer 20

A change from a mature (normal) epithelium to a different (normal) epithelium type.
Benign change.
E.g. Barrett’s oesophagus (change from non-keratinised squamousmucosa to columnar mucosa due to reflux).

Question 21

Define dysplasia.

Answer 21

When applied to organs = disordered growth of mature cells, often congenital abnormalities.
When applied to cells = abnormalities which are known to progress to cancer.

Question 22

Define necrosis.

Answer 22

Appearance of pathological cell death.
- Associated with characteristic cellular appearances including loss of membrane integrity.
- Release of cell constituents from necrosing cell triggers inflammation.Usually affects large numbers of adjacent cells
- E.g. tuberculosis: caseous necrosis (dead tissue resembles cheese)

Question 23

Define apoptosis.

Answer 23

Programmed cell death.
Physiological process of cell death (as opposed to necrosis which is pathological).
- Often part of a physiological process such as renewal of epithelia
- May be induced by noxious stimuli
- Integrity of cell membrane retained – a “cleaner” form of cell death which doesn’t release cell products that induce inflammation

Question 24

What is ischemia?

Answer 24

Insufficient vasulcar supply.

Question 25

What is an embolus?

Answer 25

Something foreign carries in the blood that can block a BV e.g. bullet wound- shrapnel travels in blood around the body.

Question 26

What is a thrombus?

Answer 26

A blood clot.

Question 27

Which triad states the 3 factors required for a venous thrombosis?

Answer 27

Virchow’s Triad: vessel wall (endothelial) injury, stasis of blood and hypercoagulability of blood.

Question 28

What does the term thrombosis refer to?

Answer 28

The process of forming a thrombus.

Question 29

How may the body manage a thrombus itself?

Answer 29

• A thrombus can block a vessel and be organised and form new vessels (angiognesis), resulting in resorption of the thrombus.

Question 30

What factors influence the type of thrombus formed?

Answer 30

Depends on the interplay between the following factors:
- Initial size of thrombus
- Factors in blood causing further thrombosis formation or breakdown
- Extent of local disease
- Consequent distrubance of flow

Question 31

What is an atheroma?

Answer 31

A plaque.
Comprised of lipid material, fibrous cap, thrombosis and inflammation.

Question 32

What is the difference between an eccentric and concentric plaque?

Answer 32

Eccentric plaque: does not occupy the entire vessel lumen.
Concentric plaque: occupies entire circumference of vessel.

Question 33

What may happen if a plaque ruptures?

Answer 33

The material of the plaque goes into circulation, or provides materials for additional thrombosis.

Question 34

What may atherosclerosis lead to?

Answer 34

Reduced blood supply, could lead to death of cells supplied by the effected vessels e.g. may cause myocardial necrosis.