Flashcards in L17- Abnormalities of growth, differentiation and morphogenesis Deck (17):
What are cellular adaptions?
Adaptations are reversible* (often) changes in cellular:
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
-Excess hormones/ growth factors
Examples of Hyperplasia?
hyperplasia of the glandular and stromal tissue in the breast
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)
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.