EYELIDS Flashcards
1
Q
EYELIDS DERIVED FROM?
A
SURFACE ECTODERM
2
Q
WHAT INITIATES SEPARATION OF LIDS?
A
keratinisation of surface epithelial cells
3
Q
EYELID FUNCTIONS
A
- protection
- contributes to tear production
- spreads tears across cornea
- aids in tear drainage
4
Q
OPENING BETWEEN LIDS FORMS WHAT?
A
PALPEBRAL FISSURE
5
Q
STRUCTURE OF EYELID
A
- skin
- musculature
- fibrous layer (incl. tarsal glands)
- palpebral conjunctiva
6
Q
MUSCULATURE OF EYELIDS
A
- orbicularis oculi
- levator palpebrae superioris
- tarsal muscles
7
Q
ORBICULARIS OCULI
A
- striated voluntary
- holds lid against eye
- assists spreading tears
- contraction causes lids to close
- CN VII
- orbital part (forced lid closure)
- palpebral part (reflex blinking)
8
Q
LEVATOR PALPEBRAE SUPERIORIS
A
- striated voluntary
- found in upper lid
- becomes a tendon as it enters the lid
- involved in raising upper lid
- CN III
9
Q
TARSAL MUSCLE
A
- smooth
- sympathetic innervation
- lines levator + aids it’s action
- wide-eyed expression of fear
10
Q
FIBROUS LAYER OF LIDS
A
- gives lids shape + firmness
- contains tarsal glands (modified sebaceous glands)
11
Q
PALPEBRAL CONJUNCTIVA OF LIDS
A
- lines inner surface of lids
- mucous membrane
- non-keratinised epithelium
- forms conjunctival sac
- goblet cells produce mucin
- vascular TC provides oxygen to cornea when eye is closed
