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Semester 3 (M+M) > Eyes > Flashcards

Flashcards in Eyes Deck (89)
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1

What is the translation of ‘humor’ with regards to the eye?

Chamber (aqueous and vitreous)

2

What is the name for the gap between the cornea and the sclera?

Corneal limbus

3

How does vit A deficiency affect the eye?

Less vit A = Less rhodopsin protein = Night blindness

4

What is ptosis?

Drooping of upper eyelid

5

In the context of optics what is an aberration?

Failure of rays to converge on one focus

6

Which thalamic nucleus is involved in the visual system?

Lateral geniculate (LGN)

7

How does laser eye surgery work?

Burns surface of cornea to change it's shape

8

What is another name for eyelids? Where are the two eyelids connected and what fissue seperates them?

Palpebrae
Connected at med and lat canthus
Separated by palpebral fissure

9

What glands run along the inner margin of the eyelids and what is their function?

Tarsal glands- Secrete lipid rich product to stop eyelids sticking together

10

What is the lacrimal caruncle?

At the medical cunthus, it secretes gritty deposits which sometimes appear on your eyes in a morning

11

Which muscle closes the eyelids?

Orbicularis oculi (deep to thin layer of skin)

12

Which muscle raises the upper eyelid?

Levator palpebrae superioris

13

What is the conjunctiva?

The epithelium (stratified squamous) which covers the inner surface of the eyelids (palebral conjunctiva). The ocular conjunctiva also covers the ant surface of the eye

14

What is the cornea made of and what is it's function?

5-7 cells layer of stratified squamous epithelium
It is 2/3 of the eyes total optical power as its curvature reflects light). It has a power of about 43 diopters

15

What is the function of the lacrimal apparatus?

Produces, distributes and removes tears

16

What is the fornix?

The pocket created where the palpebral and ocular conjunctiva meet. The superiolateral fornix contains the ducts from the lacrimal gland, which provides tears and nutrient/ o2 demands for the cells of the cornea

17

What antibacterial agent is in tears?

Lysozyme (antibacterial enzyme)

18

How are tears removed?

Blinking sweeps them to medial canthus (area known as lacrimal lake) > lacrimal caruncle > lacrimal puncta (two small pores) > lacrimal canaliculi > lacrimal sac >nasolacrimal duct > inferior meatus > nasal cavity

19

What is the choroid?

Contains a network of BV's to nourish retina and other eye cells, pigmented black in humans

20

What is the macula lutea?

Oval shaped, v.yellow pigmented 6mm spot which contains the perifovea which circumscribes the parafovea which circumscribes the fovea (largest cone conc, used for high resolution central vision)

21

What is the difference between the aqueous humour and the vitreous humour?

Aqueous= Like water, continually replaced
Vitreous= Stagnant gel, produced by secretions of ciliary bodies in vitro. Provides pressure to keep everything in place

22

What are the ciliary bodies?

Ciliary muscles + ciliary processes
(Produces aqueous humour and vitreous when in vivo)

23

What are the ciliary processes?

Inward folds of the choroid between the suspensory ligaments

24

What is the sclera?

Tough fibrous coating which provides attachments for muscles

25

What kind of proteins are rhodopsin and photopsin?

G-protein coupled receptors

26

What are the different proteins in rods and cones?

Rods= Rhodopsin
Cones= Photopsin

27

Why is vitamin A important for sight?

Both rhodopsin and photopsin use conversion of retinol (11-cis to 11-trans) to activate cascades
Retinol is a slightly processed version of vitamin A

28

In a dark environment what is the pathway between the rod cell and the ganglion cell?

Rod cell fires (glutamate) which inhibits the bipolar cell so therefore the BP cell does not excite the ganglion cell and the ganglion cell does not fire

29

What is the visual pathway from rod cell to visual cortex?

Rod > bipolar > ganglion > LGN > primary visual cortex

30

What are each of the area's V1/ V5 and V8 responsible for in the visual cortex?

V1: primary visual cortex, begins processing
V5: detects motion
V8: does colour vision