Lacrimal Apparatus

Question 1

Define Lacrimal Apparatus.

Answer 1

Lacrimal Apparatus are the structures concerned with secretion and drainage of tears

Question 2

What does the Lacrimal Apparatus comprise of?

Answer 2

Comprises of

Lacrimal Glands

• Main gland
• Accessory glands

Lacrimal passages

• Puncta
• Canaliculi
• Lacrimal sac
• Nasolacrimal duct

Question 3

List the types of lacrimal apparatus.

Answer 3

1. Main & accessory lacrimal glands
2. Eyelids & their blinking action
3. Lacrimal excretory system

Question 4

What does each type of lacrimal apparatus do?

Answer 4

1.Main & accessory lacrimal glands
Secrete a tear film that protects ocular surface & helps maintain
optimal vision

2.Eyelids & their blinking action
Help distribute tears across cornea & transport tears to puncta

3.Lacrimal excretory system
Drains tears from lacus lacrimalis (Lid tear lake) into inferior
meatus

Question 5

Describe the lacrimal gland.

Answer 5

The lacrimal gland is ‘J’ - shaped and it is a serous gland

Question 6

Where is the lacrimal gland situated?

Answer 6

Situated = lacrimal fossa – upper eyelid (supero-lateral portion of anterior orbit)

Question 7

The structures responsible for the innervation of the lacrimal gland :

Answer 7

• sensory: Lacrimal br. Of Va
• sympathetic & parasympathetic :
  Consists of :
• orbital part (large & deep)
• palpebral part (smaller & superficial)

Question 8

What are orbital and palpebral parts separated by?

Answer 8

2 parts separated by lateral extension of levator palpebral

superioris

Question 9

Describe the orbital part(of the lacrimal gland).

Answer 9

Paired almond - shaped glands

Question 10

Where is the orbital part(of the lacrimal gland) located?

Answer 10

Located in a fossa on the antero-superolateral

aspect of the orbit

Question 11

The orbital part has…

Answer 11

2 surfaces, 2 borders & 2 extremities

Question 12

Where are the surfaces, borders and the extremities located?

Answer 12

• Superior surface – frontal bone
• Inferior surface – levator palpebrae superioris & lateral rectus
• Anterior border – septum orbitale
• Posterior border – orbital fat, level with posterior pole
• Lateral extremity – rests on lateral rectus
• Medial extremity – on levator

Question 13

State the size of the palpebral part(of the lacrimal gland).

Answer 13

1/3rd size of the orbital part

Question 14

What is the palpebral part(of the lacrimal part) continuous with?

Answer 14

Continuous with orbital part

posteriorly

Question 15

Where is the palpebral part found?

Answer 15

Found beneath levator

aponeurosis

Question 16

Lacrimal gland innervation - Parasympathetic :

Answer 16

1. Preganglionic fibres are carried in the greater petrosal nerve (br.
   of facial nerve) & then the nerve of pterygoid canal, before
   synapsing at the pterygopalatine ganglion (sphenopalatine ganglion)

Question 17

Lacrimal gland innervation - Parasympathetic :

Answer 17

2. Postganglionic fibres leave the ganglion & travel with the
   maxillary nerve & finally the zygomatic nerve

Question 18

Lacrimal gland innervation - Parasympathetic :

Answer 18

3. These nerves then reach the lacrimal gland within lacrimal
   nerve
4. Stimulates fluid secretion from the lacrimal gland

Question 19

Lacrimal gland innervation - Sympathetic :

Answer 19

1. Fibres originate from the superior cervical ganglion & are
   carried by the internal carotid plexus & deep petrosal nerve

Question 20

Lacrimal gland innervation - Sympathetic :

Answer 20

2. They join with the parasympathetic fibres in the nerve of

pterygoid canal & follow the same route to supply the gland

Question 21

Lacrimal gland innervation - Sympathetic :

Answer 21

Inhibits fluid secretion from the lacrimal gland

Question 22

Lacrimal passages - Lacrimal puncta :

: How many are found in each eye; where are is it situated?

Answer 22

• One in each eyelid

- Situated near the posterior border of the 6 mm from medial canthus

Question 23

Lacrimal passages - Canaliculi :

How many are found in each eye; where does it commence?

Answer 23

• One in each eyelid

- Commences at the punctum & carries tears to lacrimal sac

Question 24

Lacrimal passages - Lacrimal sac : 
Where does it lie?
What is it covered by?
What is the upper part known as?
Where does the lower end narrow?

Answer 24

• Lies in lacrimal fossa (fossa formed by lacrimal bone & frontal process of
  maxilla)
• Covered by lacrimal fascia (anterior to fascia is the medial palpebral ligament)
• Upper part of the sac known as the fundus
• Lower end narrows as it opens into nasolacrimal duct

Question 25

Lacrimal passages - Nasolacrimal duct : What does it open into? What happens to the tears secreted by the lacrimal glands?

Answer 25

- Opens into inferior meatus of the nose - Tears secreted by lacrimal glands into conjunctival sac are drained by the lacrimal passage to the nose

Question 26

Tear production : Why is normal tear formation necessary?

Answer 26

``` Normal tear formation necessary to keep eye moist is provided by a continuous secretion from accessory lacrimal glands scattered throughout conjunctival sac ```

Question 27

Tear production : What causes excessive production of tears?

Answer 27

Excessive production of tears i.e. crying, is due mainly to reflex nervous stimulation of main lacrimal gland

Question 28

Tear production : Describe tear production under normal conditions.

Answer 28

Under normal conditions, tear production just exceeds that lost by evaporation; remainder passes down nasolacrimal duct.

Question 29

Pathway of lacrimal fluid :

Answer 29

1. Lacrimal fluid(tears) is produced in the lacrimal gland 2. Lacrimal fluid is dispersed across the eye surface 3. Lacrimal fluid enters the lacrimal canaliculi and collects in the lacrimal sac 4. Lacrimal fluid from the lacrimal sac drains through the nasolacrimal duct 5. Lacrimal fluid enters the nasal cavity