Anatomy - Eye Flashcards
1
Q
Eyelid
A
- upper and lower
- upper is larger and contains a muscle: levator palpebral superior
CONTENTS
- tarsal plate: fibrocartilaginous
- tarsal glands: secrete oily substances to prevent tears from overflowing
- eyelashes: protect cornea
2
Q
Conjunctiva
A
- mucous membrane covering eyelids and cornea
- keep the cornea moist
3
Q
Tears
A
- produced by lacrimnal gland (lateral orbit)
- tear production
- tear flow is across the eye, to canals, sac, duct and cavity
4
Q
External eye clinical issues
A
- eyelid cyst
- canal block
- infections: conjunctivitis
5
Q
The globe: external tunic
2 parts
A
Sclera
Cornea
6
Q
The globe, external tunic
1) Sclera
A
- posterior white fibrous tissue
- lamina cribrosa: where all the optic nerves go through sclera
- Canal of schelmm -> drains aqueaous humor to ciliary veins
FUNCTION
- maintain form of globe
- drain aqueous humor through canal of schlemm
7
Q
The globe: external tunic
2) cornea
A
- continuous with sclera
- anterior is transparent because of hydration
- avascular/lymph-free
- nourished by aqueous humour
FUNCTION
- lets light in
- focus light on retina
8
Q
The globe: middle tunic
3 parts
A
- choroid
- ciliary body
- iris
9
Q
The globe: middle tunic
1) Choroid
A
- highly vascular
- very pigmented
- sclera is loose, retina is tight
FUNCTION
- blood supply to retina
- abosrb light
10
Q
Clinical issues with external tunic of globe
A
- blocked canal of schlemm can result into increase pressure and glaucoma
- corneal transplants
- corneal reflex can test integrity of nerves V and VII
- retinal detachments between choroid and retina
11
Q
Middle tunic of globe
2) Ciliary body
A
- Continuous with choroid anteriorally and iris posteriorally
- ciliaris muscle
- suspensory ligament
FUNCTION
- suspend lens (accomodation) through suspensory ligaments
- makes aqueous hymour
12
Q
Middle tunic of globe: iris
A
- continous with ciliary body, the other and is free -> pupil
- divides front space into anterior and posterior chambers
- angle of the division is called the iridocorneal angle
- pigment because looking to posterior chooid
- sphinctor pupillae is parasympathetic innervation
- dilatator pupillae is sympathetic innervation
FUNCTION
- light control
13
Q
Clinical issue of middle tunic of globe
A
- iridocorneal angle is sometimes collapsed and blocks canal of Schlemm -> “closed angle glaucoma:
- albino - no pigment in coroid on iris
- Pupillary reflex: II and III
14
Q
Reflexes for different parts of brainstem
A
- reflex for medulla: gag reflex
- reflex for pons: corneal reflex (V, VII)
- reflex for midbrain: pupillary reflex (II, III)
15
Q
Internal tunic: retina
A
- part of the CNS, direct outgrowth of thalamus
- light sensitive: photoreceptors
