L17- Abnormalities of growth, differentiation and morphogenesis Flashcards Preview

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Flashcards in L17- Abnormalities of growth, differentiation and morphogenesis Deck (17):

What are cellular adaptions?

Adaptations are reversible* (often) changes in cellular:
Metabolic activity

DUE TO changes in the environment or demand


What is the role of adaption?

Better equips cells to survive in a new environment

Failure of adaptation may lead to sub-lethal or lethal cell injury


Cellular adaption can be Physiological or Pathological, explain each...

Physiological: Responding to normal changes in physiology or demand

Pathological: Responding to disease related changes


What are the Types of adaptive response ?

Increased cellular activity (Increased size or number of cells)

Decreased cellular activity (Decreased size or number of cells)

Change of cell function and morphology


What is hypertrophy?

Increase in size of existing cells
Increase in functional capacity

(Particularly seen in permanent cell populations esp cardiac and skeletal muscle)


What is hyperplasia?

Increase in number of cells caused by cell division
Possible in labile and stable cell populations

Can be:
Pathological- Hormonal
-Excess hormones/ growth factors
Or physiological


Examples of Hyperplasia?

hyperplasia of the glandular and stromal tissue in the breast

Cirrhotic liver
abnormal healing process leads to the formation of hyperplasia nodules of hepatocytes


What is Atrophy ?

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

Can be Pathological or physiological


Examples of Pathological Atrophy

Decreased workload (disuse atrophy)
Loss of innervation (denervation atrophy)
Diminished blood supply
Inadequate nutrition (eg cachexia)
Loss of endocrine stimulation


What is Metaplasia ?

Transformation of one differentiated cell type into another


Metaplasia – pathological examples : Pseudostratified ciliated bronchial epithelium (cigarette smoke)

Squamous epithelium


Metaplasia – pathological examples: Transitional epithelium of bladder (Bladder calculus, schistomosiasis, longstanding catheter)

Metaplasia – pathological examples:


What is Neoplasia?

new, uncontrolled growth of cells that is not under physiologic control


Adaptations of tissues and their links to neoplasia (examples)

Squamous metaplasia in cervix = CIN and squamous cell carcinoma

Glandular metaplasia in oesophagus = Adenocarcinoma

Squamous metaplasia in bladder = Squamous cell carcinoma


What is Dysplasia ?

Earliest morphological manifestation of multistage process of neoplasia (hence irreversible)

In-situ disease; non-invasive

Shows cytological features of malignancy, but no invasion


Benefits of early recognition of Dysplasia?

Recognition of dysplasia gives us a chance to treat a potentially fatal tumour before it arises; the abnormal cells have not yet acquired the capacity for invasion so they cannot spread. This is the whole basis of the cervical screening programme.


What is involution?

Involution refers to the shrinking or return of an organ to a former size

E.g The thymus continues to grow between birth and puberty and then begins to atrophy

E.g Involution is the process by which the uterus is transformed from pregnant to non-pregnant state