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Special sense Physiology > EYE1 > Flashcards

EYE1 Flashcards

1
Q

بسم الله الرحمن الرحيم وبه نستعين
__________________________
Special senses have distant teleceptors except for ?

A

Taste

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2
Q

Mention layers of Eye

A

Outer fibrous coat
Middle vascular pigmented coat
inner nervous coat

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3
Q

Describe outer fibrous layer of eye

A

Formed of :
Cornea the anterior tranparent 1/6
Sclera the remaining 5/6 hardest strcutre of eye
Covered anteriorly by conjunctiva
Connected to cornea at Limbus froming corneoscleral junction

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4
Q

Uveal tract show structures

A

Middle vascular pigmented coat:
1-Choroid :- 5/6 of coat vessels + melanin
2-Ciliary bodies: ciliary muscle + suspensory ligaments + ciliary process for secertion
3-Iris : perofrated disc with hole of pupil
containing muscles: constrictor + dilator pupillae

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5
Q

Explain retina structure

A

it is inner nervous coat of Eye
containing 10 layers and Rods and cones photorecpetors +
Macula lutea + Fovea centralis containing the Cones
Optic disc or blind sopt the side of exit of optic nerve
3mm from nasal side of macula

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6
Q

Mention contents of eye ?

A

Lens
Aquos humor water infront of lens
Viterous humor jelly fluid of hyalouronic acid + collagen + h2o behind the lens

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7
Q

Mention chabers of eye ?

A

Anterior chamber : between cornea and iris containing aqueous humor
Posterio chamber between iris and lens containing aqueous
Viterous chamber between lens and retina containig the Viterous body humor

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8
Q

Electromagnetic radiation may be:
- Short wave length e.g.?
- Long wave length e.g. ?

A

short x ray
long radio

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9
Q

the visible portion of the electromagnetic radiations

A

Light from 400 to 700nm

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10
Q

Mention imp of ultraviolet and signifcance of infraRed?

A

Ultraviolet ? FKD
Darkening skin
Killing bacteria
Forming Vit D
________________
InfraRed :
Heating effect

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11
Q

When light falls on object it is ?

A

Absorbed
Reflected
Rrefracted
according to the object

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12
Q

Refraction is: the change in ,,,,,,and/or ,,,,,,of light

A

velocity- direction

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13
Q

Refercation depends on ?
1-
2-
3-
?

A

1-Refraction index
2-Angle of incidence
3-degree of curvature

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14
Q

Refrative index of medium RI
?

A

RI = Velocity of light in air/Velocity of light on medium it is always > 1

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15
Q

☺1 RI of aqueous:
☺2 RI of vitreous:
☺ 3RI of cornea:
☺4 RI of Lens:
☺5 RI of air:

A

AQUOUS = 1.33
VITEROUS =1,34
Cornea=1.38
LENS=1,4
air = 1

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16
Q

If light falls:
 Perpendicular:
 Forming and angle:

A

prependicular: Only velocity changed
Angle : Veolcity + direction changed

17
Q

Degree of curvature and refreaction !
a) Concave lens: →
b) Convex lens: →

A

Concave diverge parallel rays
Conves converge parallel rays

18
Q

 Center of lens = ,,,,,point
 Point of focusing = ,,,,,point
 Focal length =

A

cente= nodal
focal ponint
______________
focal length the distance between nodal and focal points

19
Q

Power of lens = ?

A

1/focal length (m) =
1/object distance + 1/image distance

20
Q

The focal length of whole eye = ?
so the the power = ?

A

17mm
60 diopeters

21
Q

The focal length of whole eye = ?
so the the power = ?

A

17mm
60 diopeters called resting eye power

22
Q

The most imp part of eye for refraction ?

A

-The anterior Surface of cornea: responsible for 40 Diopters
because most of refraction occurs at the air-cornea interface

23
Q

any change in object distance → a change in lens dioptric power.
why?

A

Lens formula:
𝟏/
𝐟𝐨𝐜𝐚𝐥 𝐥𝐞𝐧𝐠𝐭𝐡 𝐢𝐧 𝐦𝐞𝐭𝐞𝐫𝐬
=
𝟏/
𝐨𝐛𝐣𝐞𝐜𝐭 𝐝𝐢𝐬𝐭𝐚𝐧𝐜𝐞 𝐢𝐧 𝐦𝐞𝐭𝐞𝐫𝐬
+
𝟏/
𝐢𝐦𝐚𝐠𝐞 𝐝𝐢𝐬𝐭𝐚𝐧𝐜𝐞 𝐢𝐧 𝐦𝐞𝐭𝐞𝐫𝐬
but image distance is constant
so any change in object distance changes the focal length
if increased the focal length decreases increasing the power of lens

24
Q

Mention protective mechanisms of eye

A

Bony orbit for post 2/3
Eyelid for ant 1/3 and during sleep forcovering eye
Tear film moistening and protecting cornea and conjunctivaR
Eye reflexes

25
Q

Explain conjunctival reflex ?

A

Tacilte stimulation or irritation of cornea + conjunctiva causeing reflex blinking

26
Q

explain auriclopalpebral reflex

A

auditory stimulation on sudden high amplitude may cause closing of both eyes

27
Q

Compare between dazzle and menance reflexes

A

Both are visual reflexes
Dazzle on exposure to shining light causing blinking
Menance when an object comes near to your eye causing blinking

28
Q

Explain lactrimnal apparatus structures

A

Secretory : Lacrimal gland supplied by facial nerve
Excretory : Lacrimal puncta + Lacrimal canaliculi
+ larimal sac + nasolarciaml duct to inferior meatus

29
Q

Mention functions of tears

A

الطفل معجبوش العصير (فكب كله )ودمع فين بقا فايدة الدموع ؟
فكب كله FCP CLH
-Filling minute irregularity in the cornea smoothing its surface maintianing light referaction
-Corneal nutrition diffusion of o2 from tears to cornea
-Protection containing lysozymes lactoferrin and Igs
-Cleansing from foreign bodies and irritants
-Lubricant for free movement of eye ball
-Healing delivering WBCS to wounds

30
Q

Mention structures of tears

A

Lipid from Meibomian glands preventing evaporation
Water from lacrimal glands
Mucous from goblet cells for filling irregularities of cornea + makine cornea and conjunctiva hydrophilic for spreading of tears

31
Q

Mention types of Tear secretion

A

1-Basal spontaneous all over the day
2-Reflex due to irritaton affetent CN5 efferent CN7
3-physic emotions stimulating parasypmathatic for tears

32
Q

Mention causes of Dry eye ?

A

Dxi
-Decreased secretion of teras due to
Inflammation or Tumor or Congenital absence of lacrimal gland
- Xerosis : decreasing Vit A decreasnig mucuous decreasing spread of tear
-Impaired eyelid Causing more evaporated teras and Exposure Keratitis

33
Q

Causes of Increased tears mention ?

A

1-Foreign bodies
2-Inflammation + obstruction of Drainage

34
Q

Mention sensory supply of eye

A

Optic nerve for vision
Trigeminal For sensation giving opthalmic giving short ciliary nerves

35
Q

Mention somatic motor innervation of eye

A

Cranial nerves 3,4,6 supplying extraocular muscles

36
Q

Mention autonmoic supply of Eye

A

Sympathatic from LHCs of upper 2 thoracic segments for Mydriasis by dilator pupillae and Relaxation of Ciliary muscle
_________________________________
Parasympathatic from Occulumotor nucleus for
Miosis by constrictor pupillae + Cotraction of ciliary muscler for accommodation

37
Q

Painful structures of eye?

A

Cornea + iris + ciliary bodies

38
Q

Non painful structures of eye ?

A

LENS + Viterous Humor + Retina + Choroid

39
Q

الحمدلله رب العالمين

A

Special sense Physiology (8 decks)

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