Abnormalities of Growth, Differentiation & Morphogenesis (17)

Question 1

Cellular adaptation

Answer 1

Allows tissues and organs to cope with changes in demand (physiological/pathological)

Question 2

What adaptations can occur? Change in..

Answer 2

Size, number, phenotype, metabolic activity, function due to changes in environment/demand (reversible)

Question 3

Failure of adaption leads to

Answer 3

Sub-lethal/lethal cell injury (marked susceptibility to injury, stimulus is too severe)

Question 4

Cells that don’t need to adapt

Answer 4

Fibroblasts - survive severe metabolic stress without harm e.g. absence of O2

Question 5

Cells that adapt easily

Answer 5

Epithelial cells, labile cell population - active stem cell compartment

Question 6

Cells that cannot adapt

Answer 6

Cerebral neurons - terminally differentiated, permanent cell population, high specialised function, easily damaged by environmental change

Question 7

Physiological cellular adaption

Answer 7

Responding to normal changes in physiology or demand

Question 8

Pathological cellular adaption

Answer 8

Responding to disease related changes

Question 9

Increased cellular activity leads to

Answer 9

Increase size/number of cells

Question 10

Types of adaptive response

Answer 10

Increased/decreased cellular activity, change of cell function and morphology

Question 11

Hypertrophy

Answer 11

Increase in size of cells, increase in function capacity. increased metabolism, increased synthesis of structural components (seen in permanent cell populations - cardiac/skeletal muscle)

Question 12

Hyperplasia

Answer 12

Increase in number of cells caused by cell division, possible in labile/stable cell populations

Question 13

Subcellular hypertrophy and hyperplasia

Answer 13

Increase in size and number of subcellular organelles

Question 14

Example of physiological hyperplasia

Answer 14

Hormonal, compensatory

Question 15

Example of pathological hyperplasia

Answer 15

Excess hormones, growth factors

Question 16

Clinical example of pathological hyperplasia

Answer 16

Gynaecomastia - glandular and stroll tissue in breast (high oestrogen/liver disease)

Graves disease (thyrotoxicosis)

Question 17

Atrophy

Answer 17

Reduction in size of organ/tissue by decrease in cell size and number

Question 18

Physiological atrophy

Answer 18

Embryogenesis, uterus after pregnancy/menopause

Question 19

Pathological atrophy

Answer 19

Decreased workload (disuse), loss of innervation (denervation), diminished blood supply, inadequate nutrition (cachexia), loss of endocrine stimulation, pressure

Question 20

Mechanisms of atrophy

Answer 20

Reduction in vol of individual cells, death of individual cells (apoptosis/involution)

Question 21

Involution

Answer 21

Physiological atrophy by apoptosis

Question 22

Agenesis

Answer 22

Never forms

Question 23

Aplasia

Answer 23

Primary tissue never develops into anything specific

Question 24

Dysgenesis

Answer 24

Forms wrong shape

Question 25

Hypoplasia

Answer 25

Not develop to normal size

Question 26

Metaplasia

Answer 26

Transformation of one differentiated cell type into another, better adaption to new environment, epithelium and mesenchymal tissue, physiological or pathological

Question 27

Examples of pathological metaplasia

Answer 27

Lungs - pseudo stratified ciliated epithelia > Squamous epithelium Acid reflux - oesophageal squamous epithelium > columnar (glandular) epithelium

Question 28

Examples of physiological metaplasia

Answer 28

Cervix

Question 29

Dysplasia

Answer 29

Earliest morphological manifestation of multistage process of neoplasia (irreversible), in-situ/non-invasive, abnormal nuclei, show cytological features of malignancy but no invasion