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Physiology

Terms in this set (24)

Types of Cellular Adaptions Mechanisms
1. Hyperplasia
2. Hypertrophy
3. Atrophy
4. Metaplasia
2 Types of Cellular Adaptions
1. Physiological - occurs due to normal/natural stressors
2. Pathological - occurs due to an abnormal stressor (something is causing it)
Define Atrophy
Loss of cell substance, decrease in the size of the cell that has at one time been normal size
Atrophy is caused by?
1. Decreased workload
2. Loss of innervation
3. Diminished blood supply
4. Inadequate nutrition
5. Loss of endocrine stimulation
2 types of hyperplasia
1. hormonal
2. Compensatory
In the proliferation of endometrium caused by hormone(s) how is hyperplasia stimulated and how is it inhibited?
stimulated by estrogen
inhibited by progesterone
Define Metaplasia
A reversible change in mature cell types, so a change of epithelium at a site, or location, from one type of epithelium to another type.
How does Metaplasia occur?
gene expression of precursor cells is altered causing change in morphology/cell type

Precursor cells
- epithelial stem cells
- undifferentiated mesenchymal cells
In Metaplasia if the cell changes from columnar to squamous how would you identify that metaplasia?
squamous metaplasia
- identify what abnormal cell type replaced the type it was supposed to be
This is an example of what adaptation?

1. "· enlargement of skeletal muscles with exercise"

2. increase in the size of the heart due to aortic stenosis. Aortic stenosis is due to a change in the aortic valve, which obstructs the orifice, resulting in the LV working harder to pump blood into the aorta
1. Physiological Hypertrophy adaptation

2. Pathological Hypertrophy adaptation
This is an example of what kind of adaptation?

Barrett esophagus - this is due to the reflux of gastric content into the esophagus, which causes the epithelium type to convert from squamous to glandular.
Glandular metaplasia i
This is an example of what adaptation?

After partial hepatectomy, liver resection triggers mitotic activity within 12 hours.
Compensatory hyperplasia
This is an example of what kind of adaptation?

Respiratory epithelium changes from pseudostratified columnar epithelium to squamous epithelium due to toxins in cigarette smoke
Squamous metaplasia in the respiratory epithelium of smokers

-caused by stem cells altering their gene expression (this is how lung cancer can occur - risk of developing a mutation if metaplasia persists)
This is an example of a combination of what 2 adaptation?
Uterine growth during the first weeks of pregnancy, however, is accomplished by the increase in the number of myometrial; but as gestation progresses the size of the myometrial increase.
Combination of hyperplasia (an increase in cell number) and hypertrophy (an increase in cell size)
This is an example of what adaptation?

"A patient begins hypertensive medication, the afterload of the heart will decrease and the heart doesn't have to work as hard. Because there is not as much pressure to "push" against the myocytes will decrease and return back to normal size."
Atrophy
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