Cellular adaptation Flashcards

1
Q

What cellular adaptations are possible and what are they due to?

A
Size
Number
Phenotype
Metabolic activity
Function
due to changes in the environment or demand
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2
Q

What is the role of cellular adaptation?

A
  • Acquire new, steady state of metabolism and structure
  • Better equips cells to survive
  • Failure of adaptation may lead to (sub)-lethal cell injury
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3
Q

Give examples of cells which cannot, can easily and don’t need to adapt.

A
CANNOT= Cerebral neurons, terminally differentiated, permanent cells
DON'T= Fibroblasts, survive severe metabolic stress without harm
EASILY= epithelial, labile, active stem cells
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4
Q

What are physiological and pathological cellular adaptations?

A
Physiological= Responding to normal changes in physiology or demand
Pathological = Responding to disease related changes
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5
Q

What are types of adaptive responses?

A
  • Inc cellular activity= inc size/no. of cells
  • Dec cellular activity= Dec size/no. of cells
  • Change of cell function and morphology
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6
Q

What is the point of hypertrophy?

A
  • Increase in functional capacity
  • Increased synthesis of structural components
  • Increased metabolism
  • Particularly in permanent cell populations-cardiac/skeletal muscle
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7
Q

What are problems associated with left ventricular hypertrophy?

A
  • VT/VF/sudden cardiac death

- Ectopic beats leading to abnormal rhythm

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8
Q

Give an example of sub cellular hypertrophy

A
  • Inc in size of certain organelles

- Smooth ER hypertrophy in hepatocytes in barbiturate use= inc metabolism of other drugs

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9
Q

What is Graves disease?

A
  • Autoantibody binds to and switches on TSH recpetor
  • Leads to prolonged, uncontrolled hyperplasia of thyroid and hyperthyroidism
  • Eye signs= exophthalmos by abnormal deposits of ground substance in orbital tissues
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10
Q

Give examples of pathological and physiological atrophy

A
Pathological= localised/generalised
Physiological= embryogenesis, uterus after pregnancy/menopause
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11
Q

What does pathological atrophy lead to?

A
  • Dec workload (disuse atrophy)
  • Loss of innervation (denervation atrophy)
  • Diminished blood supply
  • Inadequate nutrition (cachexia)
  • Pressure
  • Loss of endocrine stimulation
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12
Q

What are developmental causes of reduced cell mass?

A
  • AGENESIS= failure of embryonic cell mass to differentiate to organ-specific tissue
  • APLASIA= failure of organ tissue to become an organ by structural organisation
  • DYSGENESIS= failure of organ to grow to full size
  • HYPOPLASIA= failure of ‘normal’ organ
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13
Q

What is metaplasia?

A
  • Transformation of one differentiated cell type to another
  • Transdifferentiation of stem cells
  • Better adaptation to environment
  • Can affect epithelium/mesenchymal tissues
  • Physiological (cervix) or pathological
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14
Q

Give some examples of pathological causes of metaplasia

A
  • Psuedostratified ciliated bronchial epithelium= cigarette smoke= squamous epithelium
  • Transitional epithelium of bladder= longstanding catheter, schistomosiasis, bladder calculus= squamous epithelium
  • Fibrocollagenous tissue=chronic trauma= bone
  • Oesophageal squamous epithelium, acid reflux, columnar epithelium
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15
Q

Name the adaptations and the potential cancer that can be caused

A

-Squamous metaplasia in cervix= CIN & squamous cell carcinoma
-Squamous metaplasia in bronchus= Dysplasia & squamous cell carcinoma
-Glandular metaplasia in oesophagus= Adenocarcinoma
-Parathyroid hyperplasia due to chronic renal failure= Adenoma
Endometrial hyperplasia due to inc oestrogen= Adenocarcinoma

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16
Q

Describe the term dysplasia

A
  • In-situ
  • Earliest morphological manifestation of multistage process of neoplasia
  • Shows cytological features of malignancy but no invasion