Anat and physiology of vision 1 Flashcards Preview

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Flashcards in Anat and physiology of vision 1 Deck (47):
1

4 function of eye

1. transmit light to retina
2. refract light so it is focussed on retina ( cornea and lens)
3. transduce light into an electrical signal (rod and cones)
4. process this signal before it goes to CNS (middle retinal layer)

2

2 segments of eye and what is in them

1. anterior - anterior and posterior chambers
2. posterior - vitreous, retina, choroid and nerve

3

6 contents of anterior segment

1. sclera
2. cornea
3. ant. chamber
4. iris
5. ciliary body
6. lens

4

what is sclera

white outer coat of eye - perforation posterior for optic nerve and site of muscular attachment

5

what is conjunctiva

clear modified mucous membrane covering the sclera

6

3 functions of conjuntiva

1. protects globe
2. produces part of tear film
3. vascular

7

3 portions of conjuntiva

1. palpebral
2. forniceal
3. bulbar

8

what is episclera

vasular plexus between conjunctiva and sclera

9

2 layers of episclera

superficial and deep vessels

10

what is refractive power and focus of lens and cornea

cornea - 2/3 and fixed
lens - 1/3 and variable

11

3 reasons cornea is transparent

1. avascular
2. uniform structure
3. deturgescence - dehydrated

12

what is nerve supply to cornea

V1

13

5 layers of cornea

1. epithelium - non kerat. strat squamous - regenerates
2. bowmans - dense collagenous
3. stroma - 90% - regular collagen - doesn't regen
4. descemets - basement membrane
5. endothelium - monolayer for hydration

14

what is diff between sclera and cornea

sclera is same basic components, but is irreg. collagen and is not opaque

15

2 ways cornea can lose transparency

1. trauma - produces a scar
2. loss of endothelial function - swelling

16

4 parts of lens

1. capsule
2. epithelium
3. nucleau
4. cortex

17

what is a cataract

any opacity in the lens

18

3 types of cataracts and their causes

1. cortical
2. nuclear sclerosis - aging
3. posterior subcapsular - steroid, diabetes

19

2 types of lenses that can be put in surgically

1. posterior chamber
2. anterior chamber

20

3 parts of the uvea

1. iris
2. ciliary body
3. choroid

21

what is div. of anterior and posterior segments

iris

22

function of iris

controls amount of light coming into eye

23

what is in the stroma

1. muscles
2. melanocytes
3. pigments

24

2 types of muscles and their ennervations

1. sphyincter - parasym via CN3
2. dilator - symp

25

what determines eye color

how much pigment is imbedded in stroma

26

what is ciliary body

middle part of uvea - ringlike structure located behond iris

27

2 parts of ciliary body

1. pars plicata
2. pars plana

28

2 funcitons of ciliary body

1. produce aqueous humor
2. accomodation

29

what aqueous humor

provide metabolic support to the lens and inner chamber

30

flow of aqueous humor

post. chamber>through pupil>ant. chamber> drained by trabecular network in angle

31

what causes glaucoma

obsturction of drainage of humour

32

what attaches lens to ciliary body

zonules

33

what is the near triad

1. accomodation - ciliary body constricts and relaxes the zonules
2. convergence of eyes
3. pupil constriction - to decrease spherical abberation

34

what is vitreous humor made of

99% water, 1% collgen - gel

35

where does vitreous attach

optic nerve, retinal blood vessels, macula

36

4 parts of retina

1. optic disc
2. macula
3. vessels
4. peripheral retina

37

how many layers in retina

10 - light passes trough 8 to hit rods and cones

38

what is at base of retina and importance

retinal pigmented epithelium - BRbarrier and support

39

what is choroid

layer around retina that provides much of the metabolic requirements to retina

40

what are 4 extraocular parts of the eye

1. bony orbits
2. eyelids
3. lacrima system
4. extraocular muscles

41

what is weakest part of the orbit

the floor

42

3 opening into the orbit and what passes through them

1. optic foramen - optic nerve and opthalmic artery
2. sup orbital fissure - CN 3,4,V1,6
3. inf orbital fissure - sympathetics and vessels

43

which is only muscle not attached to tendinous ring

inf. oblique

44

what closes lid

obicularis oculi - CN 7

45

2 innervations of the lid

1. CN3 to open
2. sympathetics via mullers muscle

46

3 layers of tear film, where produced and function

1. mucin - by conjuntiva - adhernce
2. aqueous - lacrima glands - bulk of film
3. lipid - meibomian gland in lid - reduces evap

47

drainage path of tear

punctum>canaliculi>lacrimal sac>nasolacrimal duct

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