Anatomy of orbital appendages Flashcards
what are the layers of the eyelid:
- skin and cilia
- subcutaneous tissue
- skeletal muscle
- tarsus
the functions of the orbital septum (fibrous membrane)
- connects tarsal part with margins of the orbit
- ant bounds orbital fat within orbit
- helps limit infections between face and orbit
lien entre orbicularis oculi and palpebral ligaments:
The medial and lateral palpebral ligaments anchor the orbicularis oculi muscle at the corners of the eyelids
cilia functions:
- prevents from foreign particles
- prevents evaporation of the tear film
- sensory receptors
ciliary glands location + function:
- The ciliary glands produce a small amount of oily secretion that helps to lubricate the eyelashes and the margin of the eyelids, working with other glands (such as the Meibomian glands) to maintain eye moisture and prevent the eyelids from sticking together.
- located along the edge of the eyelids, near the base of the eyelashes
conjuctiva functions:
- keep surface of eyes + eyelids lubricated
- protects ocular surface from microbial infection
tear film (what it’s made of + function):
- Made of water and contains electrolytes and proteins
- Function: Lubricant for the eye + Protects it from infections
functions of inferior turbinate + inferior meatus:
- The inferior turbinate (or inferior nasal concha) is one of three pairs of bony, shelf-like structures called turbinates located on the lateral wall of each nasal cavity (the other two pairs are the middle and superior turbinates). The turbinate bones are covered by mucous membrane, which is rich in blood vessels, and they help to regulate airflow, humidify the air, and trap particles like dust and allergens.
- The inferior meatus is a passageway or space located directly beneath the inferior turbinate.
The nasolacrimal duct (which drains tears from the eyes) opens into the inferior meatus. This is why tears can sometimes lead to a runny nose, as they drain from the eyes into the nose through this duct.
The inferior meatus allows for airflow and drainage within the nasal cavity. It plays a role in directing air toward the lungs and in the drainage of mucus and tears.
anatomical relationships of lacrimal glands:
- Superior – zygomatic process of frontal bone
- Anterior – orbital septum
- Posterior – orbital fat
- Inferolateral – lateral rectus muscle
the 2 main parts of the lacrimal gland:
Orbital– larger and sits on the lateral margin of the levator palpabrae superioris muscle.
Palprebral– smaller and is located along the inner surface of the eyelid.
lacrimal gland (how it works = how fluid is transmitted):
- (knowing that it’s a tubuloacinar gland)
- The lacrimal fluid produced by the gland is secreted into excretory ducts, which empty into thesuperior conjunctival fornix. The fluid is then ‘spread’ over the cornea by the process of blinking.
arterial supply of lacrimal gland:
lacrimal artery = from ophthalmic artery = branch of internal carotid
venous and lymphatic drainage of lacrimal gland:
- Venous drainage is via thesuperior ophthalmic vein, and ultimatelyempties into the cavernous sinus.
- Lymphatic drainage is to thesuperficial parotid lymph nodes.They empty into the superior deep cervical nodes
tear film layers and functions:
- oil layer: meibomian glands = avoids evaporation
- water layer: lacrimal glands = lubricates + allows blinking + washes away debris + forms smooth surface
- mucin layer: goblet cells of conjuctiva = attaches film to eye + spreads water evenly
flow of tears (the path):
- simulation of parasymp CN III
- secretion of fluid into conjunctival fornix
- into conjuctival sac
- gravity + blinking
- across cornea = removes dust
- capillary action across puncta
- lacrimal sac
- inferior nasal meatus
