Define metaplasia? give examples and additional information also?

Answer 1

Metaplasia is defined as the transformation of one type of one mature differentiated cell type into another mature differentiated cell type, as an adaptive response to some insult or injury. By such a change in differentiation (and hence patterns of gene expression) the cells are more resistant to the effects of the insult. It is usually a reversible phenomenon.

Examples include:

Squamous metaplasia of the columnar epithelial cells of salivary gland ducts when stones are present.

Squamous metaplasia of the transitional epithelium of the bladder when stones are present or associated with infection with the parasite Schistosoma haematobium.

Development of glandular epithelium (glandular metaplasia) in the oesophagus in patients with gastric acid reflux. This is called Barrett's esophagus.

Osseous metaplasia in connective tissue.

The significance of these events is that they indicate insults occurring and in some situations they may be associated with pre-malignant states, as is the case in Barrett's esophagus. Note that metaplasia does not itself progress to neoplasia but the insults) that induce metaplasia may induce tumour development.

The term transdifferentiation can be a synonym for metaplasia. In established tumours transdifferentiation [or metaplasia] can occur but it is usual to restrict the term metaplasia to events in non-neoplastic tissues.

Answer 2

Define Metaplasia

Answer 3

Metaplasia Definition

Answer 4

Transformation of cells.

Answer 5

http://www.google.com/search?q=define%3A+metaplasia&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

http://en.wikipedia.org/wiki/Metaplasia