Holocrine

Holocrine is a term used in histology to describe a method of secretion in which the entire cell is destroyed to release the substances inside. This is in contrast to other types of secretion such as merocrine and apocrine, which do not involve the destruction of the cell. Holocrine secretion is characteristic of the sebaceous glands in the skin, which secrete sebum, a complex mixture of lipids, to lubricate the skin and hair.

Process

In holocrine secretion, the cell's cytoplasm is filled with vesicles containing the substance to be secreted. The cell then dies and disintegrates, releasing the vesicles and their contents. This process is slow and continuous, and the cell is replaced by a new one from the basal layer of the epithelium.

Examples

The most common example of holocrine secretion is the sebaceous glands of the skin. These glands secrete sebum, a complex mixture of lipids, onto the hair and skin to lubricate and protect them. Other examples of holocrine glands include the meibomian glands in the eyelids, which secrete a lipid-rich substance that prevents the evaporation of the eye's tear film, and the ceruminous glands in the ear, which secrete earwax.

See also

• Merocrine
• Apocrine
• Sebaceous gland
• Meibomian gland
• Ceruminous gland

References

Holocrine Resources
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