Cellular adaptations

Question 1

What are the 4 types of cellular adaptations?

Answer 1

• Hypertrophy
• Hyperplasia
• Atrophy
• Metaplasia

Question 2

Why do cellular adaptions occur?

Answer 2

Due to change in the microenvironment of the cell- may potentially be reversible

• Adapt via metabolic/structural means to survive and maintain homeostasis
• Can have pathological or physiological stimuli

Question 3

What are the causes of cellular adaptations?

Answer 3

• Nutritional deficiencies/excesses
• Damage caused by immune system
• Physical or chemical agents
• Infections or anoxia
• Genetic

Question 4

What are the molecular mechanisms for cell adaptation?

Answer 4

• Growth factors
• Up/down regulation of metabolic cell receptors
• New proteins synthesised
• Changes the way the cell looks/functions

Question 5

Define growth in terms in cell adaptation

Answer 5

Increase size- synthesis of specific tissue components (multiplicative, auxetic, accretionary or combined)

Question 6

Define differentiation

Answer 6

Cell has a specialised function and phenotype- selective expression of genes

Question 7

Define morphogenesis

Answer 7

Highly complex development of structural shape and form

Question 8

Describe the different structural adaptations

Answer 8

• Increase in cellular activity
• Decrease in cellular activity
• Change in cell morphology (change in cell differentiation)

Question 9

What are the terms for the change in cell size?

Answer 9

• Decrease- atrophy

- Increase- hypertrophy

Question 10

What are the terms for a change in cell number?

Answer 10

• Decrease- hypoplasia

- Increase- hyperplasia

Question 11

What is the term for a change in cell differentiation?

Answer 11

Metaplasia

Question 12

Describe hypertrophy

Answer 12

• Size and functional capacity increase due to increase in the synthesis of structural components with increased metabolism
• E.g. left ventricle hypertrophy (hypertension)
• E.g. athlete skeletal muscles

Question 13

Describe atrophy

Answer 13

• Decrease in size of tissue, cell shrinkage (apoptosis)/ decrease in number
• Pathogenesis, loss of endocrine stimulation, disuse, diminished blood supply, loss of nerve supply and pressure

Question 14

Describe hyperplasia

Answer 14

• Increase in cell number due to increased cell division
• Co-exist in tissue
• Pathological predisposes to cancer
• E.g. uterine enlargement and prostatic hyperplasia

Question 15

Describe metaplasia

Answer 15

• 1 cell type differentiates to another
• Benign and reversible
• Squamous metaplasia
• Some may predispose to cancer

Question 16

Describe cervical transformation and screening programme

Answer 16

• Transformation zone located between original squamo-columnar joint and junction between metaplastic squamous epithelium and endocervical columnar epithelium
• Screening programme aims to detect pre-cancerous changes in cervical epithelium

Question 17

Describe ectopia

Answer 17

• Heterotopia
• Presence of normal-looking tissue in the wrong place as a developmental abnormality
• Congenital- due to embryonic cells getting lost (abnormal location- not metaplastic)
• Inlet patch- not continuous with gastric mucosa- congenital
• Defect in embryogenesis