Cellular and Tissue Reactions

Question 1

Define Hypertrophy

Answer 1

Increase in SIZE of cells, fibres or tissues without an increase in number

Question 2

Define Atrophy

Answer 2

Reduction in the SIZE of cells, fibres or tissue

Question 3

Define Hyperplasia

Answer 3

An increase in the NUMBER of individual cells in a tissue (size may or may not increase)

• Growth will reach equilibrium and is not indefinite (e.g. RPE hyperplasia secondary to trauma)

Question 4

Define Hypoplasia

Answer 4

Arrested development of tissue during embryonic life e.g. Aniridia

/Failure of developing organ to reach its full size

Question 5

Define Aplasia

Answer 5

Lack of development of tissue in embryonic life e.g. optic nerve aplasia

Question 6

Define Metaplasia

Answer 6

Transformation of 1 type of tissue into another type

e.g. Anterior subcapsular cataract fibrous metaplasia of lens epithelium

This can arise due to chronic irritation and will usually involve columnar or cuboidal epithelium changing to squamous epithelium.

Question 7

Define dysplasia

Answer 7

Abnormal growth of tissue with increased mitosis and reduced differentiation e.g. Retinal dysplasia

Question 8

Is Dyplastic tissue invasive?

Answer 8

No

And it does NOT pass through the basement membrane