PP - Tissue repair Flashcards
Polyp Def:
- a mass, that projects above the mucosal surface to form macroscopically visible structure
- this term says us nothing about its histological structure
Where are the polyp the most common?
in the gut- the mass that protrudes into the lumen
What are the shapes of a polyp?
- pedunculated
- sessile
What can be the cause of polyp?
- hyperplasia or abnormal mucosal maturation, inflammation or architecture
^these polyps are NON-neoplastic - others may be caused by submucosal or mural tumours
True neoplastic lesions:
the polyps that arise as a result of epithelial proliferation and dysplasia
Hypertrophy:
- increase in the size of cells resulting in increase in the size of the organ
- no new cells, just bigger, enlarged cells
Hyperplasia:
increase in cell number
What can only undergo hypertrophy?
The striated cell muscle cells in both skeletal muscles and heart can undergo only hypertrophy because in the adult they have limited or no capacity to divide
What are the mechanism of myocardial hypertrophy?
- mechanical triggers such as strech
- trophic triggers such as activation of alfa-adrenergic receptors
In which cases do we have pressure-overloaded ventricles?
- hypertention
- aortic valve stenosis
Developed concentric hypertrophy:
increased wall thickness and reduction of the cavity diameter
In which cases do we have volume overload?
in aortic valve insufficiency
What develops concentric hypertrophy?
pressure-overloaded ventricles
Eccentric hypertrophy (myocardial hypertrophy):
volume overload (in aortic valve insufficiency) -hypertrophy with ventricular dilation - eccentric hypertrophy
Concentric hypertrophy (Ma=macro level):
ventricular wall is thick, the heart wight is increased (normal weight ranges from 300-350g)
