Anat and physiology of vision 1

Question 1

4 function of eye

Answer 1

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)

Question 2

2 segments of eye and what is in them

Answer 2

1. anterior - anterior and posterior chambers

2. posterior - vitreous, retina, choroid and nerve

Question 3

6 contents of anterior segment

Answer 3

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

Question 4

what is sclera

Answer 4

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

Question 5

what is conjunctiva

Answer 5

clear modified mucous membrane covering the sclera

Question 6

3 functions of conjuntiva

Answer 6

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

Question 7

3 portions of conjuntiva

Answer 7

1. palpebral
2. forniceal
3. bulbar

Question 8

what is episclera

Answer 8

vasular plexus between conjunctiva and sclera

Question 9

2 layers of episclera

Answer 9

superficial and deep vessels

Question 10

what is refractive power and focus of lens and cornea

Answer 10

cornea - 2/3 and fixed

lens - 1/3 and variable

Question 11

3 reasons cornea is transparent

Answer 11

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

Question 12

what is nerve supply to cornea

Answer 12

V1

Question 13

5 layers of cornea

Answer 13

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

Question 14

what is diff between sclera and cornea

Answer 14

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

Question 15

2 ways cornea can lose transparency

Answer 15

1. trauma - produces a scar

2. loss of endothelial function - swelling

Question 16

4 parts of lens

Answer 16

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

Question 17

what is a cataract

Answer 17

any opacity in the lens

Question 18

3 types of cataracts and their causes

Answer 18

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

Question 19

2 types of lenses that can be put in surgically

Answer 19

1. posterior chamber

2. anterior chamber

Question 20

3 parts of the uvea

Answer 20

1. iris
2. ciliary body
3. choroid

Question 21

what is div. of anterior and posterior segments

Answer 21

iris

Question 22

function of iris

Answer 22

controls amount of light coming into eye

Question 23

what is in the stroma

Answer 23

1. muscles
2. melanocytes
3. pigments

Question 24

2 types of muscles and their ennervations

Answer 24

1. sphyincter - parasym via CN3

2. dilator - symp

Question 25

what determines eye color

Answer 25

how much pigment is imbedded in stroma

Question 26

what is ciliary body

Answer 26

middle part of uvea - ringlike structure located behond iris

Question 27

2 parts of ciliary body

Answer 27

1. pars plicata | 2. pars plana

Question 28

2 funcitons of ciliary body

Answer 28

1. produce aqueous humor | 2. accomodation

Question 29

what aqueous humor

Answer 29

provide metabolic support to the lens and inner chamber

Question 30

flow of aqueous humor

Answer 30

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

Question 31

what causes glaucoma

Answer 31

obsturction of drainage of humour

Question 32

what attaches lens to ciliary body

Answer 32

zonules

Question 33

what is the near triad

Answer 33

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

Question 34

what is vitreous humor made of

Answer 34

99% water, 1% collgen - gel

Question 35

where does vitreous attach

Answer 35

optic nerve, retinal blood vessels, macula

Question 36

4 parts of retina

Answer 36

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

Question 37

how many layers in retina

Answer 37

10 - light passes trough 8 to hit rods and cones

Question 38

what is at base of retina and importance

Answer 38

retinal pigmented epithelium - BRbarrier and support

Question 39

what is choroid

Answer 39

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

Question 40

what are 4 extraocular parts of the eye

Answer 40

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

Question 41

what is weakest part of the orbit

Answer 41

the floor

Question 42

3 opening into the orbit and what passes through them

Answer 42

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

Question 43

which is only muscle not attached to tendinous ring

Answer 43

inf. oblique

Question 44

what closes lid

Answer 44

obicularis oculi - CN 7

Question 45

2 innervations of the lid

Answer 45

1. CN3 to open | 2. sympathetics via mullers muscle

Question 46

3 layers of tear film, where produced and function

Answer 46

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

Question 47

drainage path of tear

Answer 47

punctum>canaliculi>lacrimal sac>nasolacrimal duct