Lacrimal Apparatus

LACRIMAL APPARATUS


LACRIMAL APPARATUS

  • Consists of secretory & excretory systems.

Secretory system consists of:

  1. Lacrimal gland & its duct
  2. Accessory lacrimal glands (Gland of Krause, Glands of Wolfring)

Excretory system consists of:

  1. Lacrimal puncta
  2. Lacrimal canaliculi
  3. Lacrimal sac
  4. Nasolacrimal duct

 TEAR

  • Major function of lacrimal apparatus is to secrete & drain tear.

Tear film consists of 3 layers:

1. Mucous / mucin layer (innermost)

  • Secreted by conjunctival goblet cells, crypts of Henle, glands of Manz.

2. Aqueous layer (intermediate):

  • This forms the bulk of the tear.
  • It is secreted by main lacrimal & accessory lacrimal glands.

3. Lipid layer (outermost):

  • Secreted by the Meibomion, Zeis & Moll glands.

CAUSES OF TEAR DEFICIENCY (Dry Eye)

1. Aqueous deficiency (Keratoconjunctivitis sicca):

  • Congenital alacrimia
  • Sjogren’s syndrome
  • Riley Da syndrome

2. Mucin deficiency:

  • Xeropthalmia
  • conjunctival scarring (Stevens- Johnson syndrome, Trachoma)

3. Lipid deficiency:

  • Congenital anhydrotic ectodermal dysplasia along with absence of meibomian gland
  • Chroniv blepheritis

4. Chronic eyelid function: 

  • Bell’s palsy
  • Exposure keratitis
  • Pterygium

LACRIMAL PUMP

  • Eyelids & the orbicularis muscle create a physiological pump which pumps the tears into the two puncta.
  • Then finally drain it into the inferior meatus through nasolacrimal duct.
  • Eyelids are opposed against the globe, this creates a capillary action for tears.
  • Orbicularis muscle contraction & relaxation creates a anegative pressure in the lacrimal sac which sucks in the ear.

Exam Important

LACRIMAL APPARATUS

  • Consists of secretory & excretory systems.

Secretory system consists of:

  1. Lacrimal gland & its duct
  2. Accessory lacrimal glands (Gland of Krause, Glands of Wolfring)

Excretory system consists of:

  1. Lacrimal puncta
  2. Lacrimal canaliculi
  3. Lacrimal sac
  4. Nasolacrimal duct

 TEAR

  • Major function of lacrimal apparatus is to secrete & drain tear.

Tear film consists of 3 layers:

1. Mucous / mucin layer (innermost)

2. Aqueous layer (intermediate)

3. Lipid layer (outermost):

  • Secreted by the Meibomion, Zeis & Moll glands.

CAUSES OF TEAR DEFICIENCY (Dry Eye)

1. Aqueous deficiency (Keratoconjunctivitis sicca):

  • Congenital alacrimia
  • Sjogren’s syndrome
  • Riley Da syndrome

2. Mucin deficiency:

  • Xeropthalmia
  • conjunctival scarring (Stevens- Johnson syndrome, Trachoma)

3. Lipid deficiency:

  • Congenital anhydrotic ectodermal dysplasia along with absence of meibomian gland
  • Chroniv blepheritis

4. Chronic eyelid function: 

  • Bell’s palsy
  • Exposure keratitis
  • Pterygium
Don’t Forget to Solve all the previous Year Question asked on LACRIMAL APPARATUS

Module Below Start Quiz

Leave a Reply

Free Mini Course on Stomach

Mini Course – Stomach

22 High Yield Topics in Stomach

in Just 2 Hours

Submission received, thank you!

Close Window
%d bloggers like this:
Malcare WordPress Security