Dictionary > Lacrimal apparatus

Lacrimal apparatus

Definition
noun
The tear-forming and tear-conducting system that includes the lacrimal glands, eyelid margins, conjunctival sac, and the tear drainage system
Supplement
Human lacrimal apparatus is a system comprised of the lacrimal glands, eyelid margins, conjunctival sac, and tear drainage system. Thus, it has two major parts that are associated with either lacrimal fluid production or lacrimal drainage system. The lacrimal fluid is produced and secreted by the lacrimal glands whereas the lacrimal drainage system includes the lacrimal sac, nasolacrimal ducts, lacrimal canaliculi, and cavity. The lacrimal glands are paired glands in the upper lateral part of the orbit. They are made up of tiny lobules. The tiny lobules are comprised in turn of several acini. Within the acini are serous cells that produce the aqueous fluid of the tear film.
The lacrimal sac, approximately 12 mm in length, is that part found in the upper portion of the nasolacrimal duct into which the two lacrimal canaliculi empty. The nasolacrimal duct is about 18 mm in length and serves as a passageway through which the tears are conducted into the nasal cavity. The lacrimal canaliculi (each, approximately 10 mm in length) are the ducts within the eyelid.
Also called:

  • apparatus lacrimalis

See also:

  • lacrimal sac
  • lacrimal gland
  • lacrimal canaliculus
  • nasolacrimal duct
  • lacrimation
  • tear


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