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Meibomian gland

Saturday 9 November 2019

Meibomius gland

WKP

Definition: Meibomian glands (often written with a small "m" and also called tarsal glands) are holocrine type exocrine glands, along the rims of the eyelid inside the tarsal plate. They produce meibum, an oily substance that prevents evaporation of the eye’s tear film.

Holocrine is a term used to classify the mode of secretion in exocrine glands in the study of histology. Holocrine secretions are produced in the cytoplasm of the cell and released by the rupture of the plasma membrane, which destroys the cell and results in the secretion of the product into the lumen.

Meibum prevents tears spilling onto the cheek, trapping the tears between the oiled edge and the eyeball, and making the closed lids airtight. There are about 50 glands on the upper eyelid and 25 glands on the lower eyelid.

Images

- https://twitter.com/NeuroEyepath/status/1235928028129054721

Pathology

- Dysfunctional meibomian glands often cause dry eyes, one of the more common eye conditions.
- They may also contribute to blepharitis.
- Meibomian cyst
- chalazion

See also

- eyelid / eyelids