What is the clinical significance of pathological hyperplasia?

Pathologic hyperplasia constitutes a fertile soil in which cancerous proliferations may eventually arise. For example, patients with hyperplasia of the endometrium are at increased risk for developing endometrial cancer.

Describe the causes and clinical importance of hyperplasia.

Hyperplasia is of two types:

A. Physiologic hyperplasia

B. Pathologic hyperplasia.

Physiologic hyperplasia:

Physiologic hyperplasia due to the action of hormones or growth factors occurs in several circumstances: when there is a need to increase functional capacity of hormone sensitive organs; when there is need for compensatory increase after damage or resection.

So physiologic hyperplasia may be

• Hormonal: proliferation of the glandular epithelium of the female breast at puberty and during pregnancy.
• Compensatory: Liver regeneration after donation of a lobe of liver.

Pathologic hyperplasia:

Most forms of pathologic hyperplasia are caused by excessive or inappropriate actions of hormones or growth factors acting on target cells.

1. Endometrial hyperplasia
2. Benign prostatic hyperplasia
3. Hyperplasia is a characteristic response to certain viral infections, such as papillomaviruses, which cause skin warts and several mucosal lesions composed of masses of hyperplastic epithelium.

What is hyperplasia?

Definition:

Hyperplasia is defined as an increase in the number of cells in an organ or tissue in response to a stimulus.

What are the types of cellular adaptation?

Adaptations are reversible changes in the size, number, phenotype, metabolic activity, or functions of cells in response to changes in their environment.
Cellular adaptation is mainly of four types:

1. Hypertrophy: Hypertrophy refers to an increase in the size of cells, that results in an increase in the size of the affected organ.
2. Hyperplasia: Hyperplasia is defined as an increase in the number of cells in an organ or tissue in response to a stimulus.
3. Atrophy: Atrophy is defined as a reduction in the size of an organ or tissue due to a decrease in cell size and number.
4. Metaplasia: Metaplasia is a reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type.

What is diffenece bteween Necrosis and Apoptosis

Give pathogenesis of Apoptosis.

Apoptosis result from the activation of enzymes called caspases. Like many proteases, casepases exist as inactive proenzymes or zymogens and must undergo enzymatic cleavage to become active.
The process of apoptosis may be divided into an Initiation phase during which some caspases become catalytically active and an execution phase during which other caspases trigger the degradation of critical cellular components. The activation of caspases depends on a finely tuned balance between production of pro-apoptotic and anti-apoptotic proteins.
Two distinct pathways converge on caspase activation:
A. The mitochondrial pathway
B. The death receptor pathway

The mitochondrial pathway or the intrinsic pathway is the major mechanism of apoptosis in all mammalian cells. It results from increased permeability of the mitochondrial outer membrane with consequent release of death inducing.