Atrophy and other stuff Flashcards
What is hyperplasia?
increase in the size of an organ due to increase in the
number of its constituent cells
* occurs in organs where cells can divide
* examples - benign prostatic hyperplasia, endometrial hyperplasia
What is hypertrophy
increase in the size of an organ due to increase in the size
of its constituent cells
* occurs in organs where cells cannot divide
* examples - skeletal muscle in athletes/bodybuilders
What is mixed hypertrophy/ hyperplasia?
- increase in the size of an organ due to increase in size
and number of its constituent cells - occurs in organs where cells can divide
- example - smooth muscle cells of the uterus during
pregnancy
What is atrophy?
- decrease in size of an organ due to decrease in size or
number of its constituent cells or both - this atrophy is used as a generic term for decrease in the
size of an organ for whatever reason - examples - Alzheimer’s dementia, quadriceps muscle
following knee injuries
What is metaplasia
- change in cell differentiation from one fully-differentiated type to another fully-differentiated type
- usually caused by a consistent change in the environment of an epithelial surface
What are some examples of metaplasia?
- bronchial epithelium from ciliated columnar epithelium to squamous epithelium in the face of continued cigarette smoke
Oesophageal squamous epithelium to glandular epithelium in continued acid reflux from the stomach (Barrett’s oesophagus)
The uterine cervix from columnar epithelium to squamous epithelium at puberty when it is exposed to the acidic environment of the vagina
What is dysplasia?
- an imprecise term for the morphological changes that
may be seen in cells (often epithelium) in the progression on to development of cancer (neoplasia) - usually defined by features seen on haematoxylin and
eosin staining down the light microscope
What is the spectrum for dysplasia?
mild, through moderate, to severe, carcinoma in situ and eventually invasive cancer
What is an example of dysplasia?
bronchial epithelium in cigarette smokers:
metaplasia from ciliated to squamous epithelium, then
development of dysplasia in the squamous epithelium
Why is the identification of dysplasia useful?
Because treatment can be given to eradicate the dysplastic epithelium and so prevent the development of invasive cancer (as shownby the NHS cervical screening programme)
Where is muscle hypertrophy seen?
In athletes due to increased muscle activity
Where is uterine hypertrophy seen?
In pregnancy
Where can hyperplasia not occur?
In myocardial cells or nerve cells
Where does atrophy occur naturally?
During the development of the GU tract
