Anatomy - Eye Flashcards Preview

Block 3 - Resp > Anatomy - Eye > Flashcards

Flashcards in Anatomy - Eye Deck (29):
1

Eyelid

- 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

Conjunctiva

- mucous membrane covering eyelids and cornea
- keep the cornea moist

3

Tears

- produced by lacrimnal gland (lateral orbit)
- tear production
- tear flow is across the eye, to canals, sac, duct and cavity

4

External eye clinical issues

- eyelid cyst
- canal block
- infections: conjunctivitis

5

The globe: external tunic

2 parts

Sclera
Cornea

6

The globe, external tunic

1) Sclera

- 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

The globe: external tunic

2) cornea

- 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

The globe: middle tunic

3 parts

- choroid
- ciliary body
- iris

9

The globe: middle tunic

1) Choroid

- highly vascular
- very pigmented
- sclera is loose, retina is tight

FUNCTION
- blood supply to retina
- abosrb light

10

Clinical issues with external tunic of globe

- 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

Middle tunic of globe

2) Ciliary body

- Continuous with choroid anteriorally and iris posteriorally
- ciliaris muscle
- suspensory ligament

FUNCTION
- suspend lens (accomodation) through suspensory ligaments
- makes aqueous hymour

12

Middle tunic of globe: iris

- 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

Clinical issue of middle tunic of globe

- 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

Reflexes for different parts of brainstem

- reflex for medulla: gag reflex
- reflex for pons: corneal reflex (V, VII)
- reflex for midbrain: pupillary reflex (II, III)

15

Internal tunic: retina

- part of the CNS, direct outgrowth of thalamus
- light sensitive: photoreceptors

16

Inner core of globe: 3 parts

- aqueous humour
- vitreous humor
- lens

17

- Inner core: 1) aqueous humor

- anterior-posterior chambers
- fluid full of aa, glucose and ascorbic acid

FUNCTION
- nourish avascular bits and lens
- maintain intraocular pressure

18

- inner core of globe

2) vitreous humour

- in vitreal chamber
- transparent gel made of water, salts and glycoprotein

FUNCTION
- structurally supports lens/retina

19

Inner core of globe

2) lens

- avascular
- suspended by suspensory ligament (attach to ciliary process)

FUNCTION
- focus on retina - accomodation - by ciliary muscle
- when suspensory ligaments pull - flat lens -> see in distance
- when suspensory ligament relaxes -> fat lens (short distance)

20

Clinical issues for inner core of globe

- lens becomes less elastic
- cataracts
- vitreal detachment - problematic if takes retina with it

21

3 types of muscles in the eye

- recti
- obliques
- levator

22

REcti muscles

- Superior, inferior, medial and lateral recti

- origin: common tendinous ring (attach to sphenoid bone)
- insertion: globe

23

Oblique muscles

SUPERIOR OBLIQUE
- origin: sphenoid
- insertion: upper lateral globe

INFERIOR OBLIQUE
- origin: maxilla
- insertion: globe (lower-lateral)

24

Levator muscles

- levator palpebran superior
- on top of all
- origin: sphenoid
- insertion, eyelid

25

Individual muscle movement
- SR
- IO
- LR
- MR
- IR
- SO
- LPS

- SR: up, intorsion, adduction
- IO: up, extorsion, abduction

- LR: abduction
- MR: adduction

- IR: down/extorsion/adduction
- SO: down/intorsion/abduction

- LPS: raise eyelid

26

Clinical issue of eye muscles

- hard to test individually
- the trick is to get the muscle to act by itself by aligning the axes

1) adduct or abduct eye
2) test up and down

27

Motor nerve supply
- oculomotor
- trochlear
- abducent

- oculomotor: SR, IR, MR, IO, LPS

- trochlear: SO

- abducent: LR

28

Sensory nerve supply

- optic: retina
- ophtalmic (V1): eye and surrounds

29

Autonomic innervation
- parasympathetic
- sympathetic

PARASYMPATHETIC
- oculomotor preganglion synapse into ciliary ganglion: sphincter pupillae, ciliary body
- facial preganglion synapse into pterygopalatine ganglion: lacrimal gland

SYMPATHETIC
- superior cervical ganglia: dilatator pupillae, LPS, lacrimal gland

Decks in Block 3 - Resp Class (44):