Atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia

Question 1

define hypertrophy

Answer 1

increase in size of a tissue caused by increase in the size of constituent cells

Question 2

define hyperplasia

Answer 2

increase in size of a tissue by an increase in the number of constituent cells

Question 3

define atrophy

Answer 3

decrease in the size of a tissue caused by a decrease in the number of constituent ells or a decrease in their size

Question 4

define metaplasia

Answer 4

(reversible) change in differentiation of a cell from one fully differentiated type to another fully differentiated type

Question 5

define dysplasia

Answer 5

the morphological changes seen in the cells in the progression to becoming cancer (pre-malignant)

Question 6

give examples of hyperplasia

Answer 6

1. pregnancy and lactation - breast epithelial cells
2. prostate- excess oestrogen
3. psoriasis - epidermal hyperplasia
4. fibromatosis- proliferation of myofibroblasts
5. cell mediated immune response- expansion of T cell popln
   liver cirrhosis - hyperplasia of hepatocytes and fibroblasts to form nodules
6. proliferation of vascular endothelial cells and myofibroblasts in scar tissue

Question 7

give examples of hypertrophy

Answer 7

1. right ventricular hypertrophy - pulmonary valve stenosis, pulmonary hypertension, VSD
2. left ventricular hypertrophy - exercise, aortic valve stenosis, systemic hypertension
3. myocardium and arterial smooth muscle in high BP

Question 8

give examples of atrophy

Answer 8

1. Mullerian duct and Wallerian duct degeneration
2. ductus arteriosius
3. post menopausal atrophy of the uterus
4. physiological in embryogenesis in hands to prevent webbing
5. thymus in early adult life
6. genitals, mandible, cerebrum and lymphoid tissue in later life

Question 9

give examples of dysplasia

Answer 9

cervical dysplasia found in screening - squamous epithelium due to HPV

Question 10

give examples of metaplasia

Answer 10

1. squamous metaplasia from the normal psudostradified columnar epithelium due to cigarette smoke
2. Barrett’s oesophagus - normal squamous epithelium replaced with columnar glandular epithelium

Question 11

What causes metaplasia?

Answer 11

adaptive response to injurious stimuli

Question 12

Give some characteristics of cells with dysplasia

Answer 12

1. increased mitosis
2. atypical morphology - pleomorphism
3. decreased differentiation

Question 13

List some causes of dysplasia

Answer 13

chronic physical/chemical injury
chronic inflammation
carcinogens