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Ophthalmology > Module 1 - Ocular Anatomy: Orbit, Ocular, Adnexa and Eyeball > Flashcards

Module 1 - Ocular Anatomy: Orbit, Ocular, Adnexa and Eyeball Flashcards

1
Q

Describe the medial walls and lateral walls of the orbit

A

Medial walls are parallel to each other, separated by the ethmoidal and sphenoidal sinuses
Lateral walls forms a 45 degree angle with the medial wall

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2
Q

What is the volume of the orbit as well as its height, width and diameter?

A

Volume: 30 cc
Height: 35 mm
Width: 45 mm
Diameter: 40-45 mm

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3
Q

These are bony cavities which contain the eye and “pear shaped” with the optic nerve representing its stem

A

Orbit

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4
Q

What are the 7 bones that make up the orbit?

A

Frontal, zygomatic, maxillary, ethmoidal, sphenoidal, lacrimal, palatine

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5
Q

What are the roofs of the orbit and its content?

A

Orbital plate of the frontal bone which contains the lacrimal gland fossa
Lesser wing of the sphenoid which contains the optic canal

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6
Q

Distance of fovea trochlearis to the orbital margin

A

4 mm

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7
Q

It serves as the pulley for the superior oblique muscle

A

Fovea trochlearis

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8
Q

Components (bone) of the medial orbital wall

A

Maxillary bone
Lacrimal bone
Ethmoidal bone
Lesser wing of the sphenoid

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9
Q

What does the medial orbital wall contains?

A

Nasolacrimal canal and lacrimal sac

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10
Q

The medial orbital wall is described as paper thin medial wall known as?

A

Lamina papyracea

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11
Q

The lateral wall of the orbit is formed by?

A

Zygomatic bone

Greater wing of the sphenoid

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12
Q

Wall of the orbit described as the thickest and strongest

A

Lateral wall of the orbit

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13
Q

What are the 4 sites of attachment for the lateral orbital tubercle?

A

Check ligament of lateral recuts muscle
Suspensory ligament of the eyeball
Lateral palpebral ligament
Aponeurosis of the levator ligament

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14
Q

It served as the roof of the maxillary sinus

A

Floor of the orbit

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15
Q

The floor of the orbit is made up of what 3 bones?

A

Maxillary bone (blow-out fractures)
Palatine bone
Orbital plate of zygomatic bone

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16
Q

It contains the infraorbital groove leading to the infraorbital foramen

A

Floor of the orbit

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17
Q

What muscle arises from the orbital floor and the only extraocular muscle that does not originate at the orbital apex?

A

Inferior oblique muscle

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18
Q

Where is the entry portal for all nerves and vessels?

A

Orbital apex

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19
Q

Where is the site of origin for all extraocular muscles except the inferior oblique?

A

Annulus of zinn

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20
Q

It contains the superior orbital fissure

A

Orbital apex

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21
Q

What are the 2 nerves located laterally (outside the Annulus of Zinn?

A

Lacrimal and frontal branch of CN V

Trochlear nerve CN IV

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22
Q

What are the 4 nerves/vessels located medially (within the Annulus of Zinn)?

A

Superior and inferior divisions of CN III
Nasociliary branch of CN V
Abducens nerve (CN VI)
Superior ophthalmic vein

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23
Q

What are the 2 nerves/veins in the inferior orbital fissure?

A

Maxillary and pterygoid parts of CN V

Inferior ophthalmic vein

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24
Q

Under the orbital apex is the optic canal which contains what artery and nerve?

A

Optic nerve

Ophthalmic artery

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25
Q

What is the main blood supply of the orbit?

A

Ophthalmic artery (1st major branch of the intracranial ICA)

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26
Q

What are the 5 major branches of the ophthalmic artery?

A 
Central retinal artery
Lacrimal artery
Muscular branches of the extraocular muscles
Medial palpebral arteries
Posterior ciliary arteries
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27
Q

Describe the course of the central retinal artery

A

It enters the optic nerve 8-15 mm behind the globe

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28
Q

What are the 2 structures that the lacrimal artery supplies?

A

Lacrimal gland

Upper eyelids

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29
Q

What artery does the muscular branches of the extraocular muscles gives off?

A

Anterior ciliary artery

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30
Q

What structures do the anterior ciliary artery supplies?

A 
Anterior sclera
Episclera
Limbud
Conjunctiva
Contributes to the major arterial circle of the iris
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31
Q

What structure does the medial palpebral arteries supplies?

A

Eyelids

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32
Q

What are the 2 branches of the posterior ciliary arteries?

A

Long posterior ciliary arteries

Short posterior ciliary arteries

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33
Q

What does the long posterior ciliary arteries supply?

A

Ciliary body

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34
Q

Describe the course of the long posterior ciliary arteries

A

Anastomose with each other to form the major arterial circle of iris

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35
Q

What are the 2 structures that the short posterior ciliary arteries supply?

A

Choroid

Optic nerve head

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36
Q

What are the 2 veins responsible for the venous drainage?

A

Superior and inferior ophthalmic vein

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37
Q

What are the 3 veins to which the superior and inferior ophthalmic veins drain?

A

Vortex vein
Anterior ciliary vein
Central retinal vein

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38
Q

What sinus does the superior and inferior ophthalmic veins communicate?

A

Cavernous sinus

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39
Q

What is this outer structure that protects the eyeball?

A

Eyelid

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40
Q

The eyelid has this gland that lubricates the eye surface which is located within the tarsus

A

Meibomian glands

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41
Q

The lids come together from where?

A

Medial and lateral canthi

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42
Q

What is this space between two open lids?

A

Palpebral fissure

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43
Q

The upper lid normally covers how many millimeters of the superior limbus?

A

2 mm

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44
Q

At what level does the lower lid placed?

A

At the level of the inferior limbus

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45
Q

What is this exposed zone between the upper and lower eyelids?

A

Interpalpebral fissure

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46
Q

What is the measurement of the interpalpebral fissures in adults?

A

27 mm long and 8-11 mm wide

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47
Q

Which is more mobile, the upper eyelid or the lower eyelid?

A

Upper eyelid

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48
Q

The upper eyelid can be raised by how many millimeters by the levator?

A

15 mm

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49
Q

What are the 9 anatomical segments of the eyelid?

A 
Skin
Margin
Subcutaneous connective tissue
Orbicularis oculi muscle
Orbital septum
Levator muscle
Tarsus
Mueller's muscle
Conjuctiva
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50
Q

What is the thinnest anatomical segment of the eyelid?

A

Skin

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51
Q

It is due to insertion of levator aponeurosis near the upper border of the tarsus (may not be present in Asians)

A

Eyelid fold

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52
Q

What is the anatomical segment of the eyelid that has no fat content and may swell due to fluid accumulation or hemorrhage?

A

Subcutaneous connective tissue

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53
Q

What is the anatomical segment of the eyelid that is considered as the punctum?

A

Lid margin

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54
Q

This line corresponds histologically to the most superficial part of the orbicularis oculi muscle

A

Gray line

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55
Q

The lid margin has a “gray line” that corresponds histologically to the most superficial part of the orbicularis oculi muscle known as what muscle?

A

Muscle of Riolan

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56
Q

What structure arises anteriorly from the gray line?

A

Eyelashes

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57
Q

What structure arises posteriorly to the gray line?

A

Meibomian gland (within the tarsus)

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58
Q

What anatomical segment of the eyelids that is arranged in a concentric band around the interpalpebral fissure?

A

Orbicularis oculi muscle

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59
Q

What are the 2 parts of orbicularis oculi?

A

Orbital

Palpebral

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60
Q

What 3 structures does the orbital part of the orbicularis oculi muscle inserts to?

A

Medial canthal tendon
Orbital rim
Corrugator supercili muscle

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61
Q

What part of the orbicularis oculi has a sphincter like control and is voluntarily controlled?

A

Orbital part

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62
Q

What part of the orbicularis oculi that is voluntary or involuntary (for normal and reflex blinking)?

A

Palpebral part

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63
Q

What anatomical segment of the eyelid that has extension of the periosteum of the root and floor of the orbit?

A

Orbital septum

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64
Q

Where does the orbitL septum attaches to?

A

Anterior surface of the levator muscle

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65
Q

What is the function of the orbital septum?

A

Barrier to spread or blood or inflammation

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66
Q

What anatomical segment of the eyelid that originates from a tendon that blends with the superior rectus and superior oblique muscles at the apex of the orbit?

A

Levator muscle

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67
Q

The levator muscle divides into what 2 structures?

A

Levator aponeurosis

Superior tarsal muscle (Mueller’s muscle)

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68
Q

Mueller’s muscle is known as what muscle?

A

Superior tarsal muscle

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69
Q

What is the function of the levator aponeurosis?

A

Produces the eyelid fold

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70
Q

What cranial nerve innervates the superior tarsal muscle?

A

Superior division of CN III

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71
Q

What is the function of the superior tarsal muscle?

A

Elevates the eyelid

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72
Q

What anatomical segment of the eyelid consist of dense connective tissue not cartilage?

A

Tarsus

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73
Q

The tarsus is attached to what structure and by what 2 ligaments?

A

Attached to the Orbital margin by the Medial and Lateral palpebral ligaments

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74
Q

What gland is a modified holocrine gland which is the oily layer of the tear film?

A

Meibomian gland

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75
Q

The facial system is derived from what artery?

A

ECA

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76
Q

The facial system gives rise to what artery and is considered to be an important landmark in DCR surgery?

A

Angular artery

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77
Q

What are the 2 systems involved in the venous drainage of the eyelid?

A

Superficial/pretarsal system

Deep/post-tarsal system

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78
Q

The superficial/pretarsal system drains to what 2 veins?

A

Internal and external jugular veins

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79
Q

The deep/post-tarsal system drains to what structure?

A

Cavernous sinus

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80
Q

What are the 2 accessory eyelid structures?

A

Pilica semilunaris

Caruncle

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81
Q

What is this accessory eyelid structures described as narrow, highly vascularized, crescent-shaped fold of conjunctival tissue?

A

Plica semilunaris

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82
Q

What type of cells is plica semilunaris rich in?

A

Goblet cells

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83
Q

What structure is plica semilunaris analogous?

A

Nictating membrane

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84
Q

What accessory eyelid structure described as small, fleshy, ovoid structure?

A

Caruncle

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85
Q

What accessory eyelid structure that contains sebaceous glands and fine colorless hairs?

A

Caruncle

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86
Q

Where is the lacrimal gland situated?

A

Frontal bone

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87
Q

What are the 2 parts of the lacrimal gland?

A

Palpebral gland

Orbital gland

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88
Q

The 2 parts of the lacrimal gland is divided by what structure?

A

Levator aponeurosis

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89
Q

The palpebral and orbital gland may occasionally be connected by what structure?

A

Isthmus

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90
Q

What gland is an exocrine gland and produces a serous secretion?

A

Lacrimal gland

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91
Q

What are the 2 types of cells found in the lacrimal gland?

A

Acinar cells

Myoepithelial cells

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92
Q

What cell found in the lacrimal gland that lines the lumen?

A

Acinar cells

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93
Q

What cell found in the lacrimal gland that surrounds the parenchyma?

A

Myoepithelial cells

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94
Q

What is the blood supply of the lacrimal gland?

A

Lacrimal artery

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95
Q

Where does the accessory glands located?

A

Eyelids

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96
Q

What 2specific glands in the accessory gland that produce basal tear secretion?

A

Glands of Krause and Wolfring

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97
Q

What are the 6 structures of the lacrimal excretory system?

A 
Lacrimal punctum
Upper and lower canaliculi
Common canaliculus
Nasolacrimal sac
Nasolacrimal duct
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98
Q

What are the 4 characteristics of a tear film?

A

Provides a smooth optical surface at the air-eye interface
Serves as a medium for removal of debris
Supply oxygen to the cornea
Protective (antimicrobial and lubricating properties)

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99
Q

What are the “tri-laminar” structures of the tear film?

A

Anterior, lipid layer
Middle, aqueous layer
Posterior, glycoprotein layer

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100
Q

What tri-lamimar structure of the tear film that comes from the meibomian glands?

A

Anterior layer, lipid layer

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101
Q

How many glands are found in the upper and lower lid?

A

30-40 in the upper lid

20-30 in the lower lid

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102
Q

What are the 4 functions of the anterior layer of the tear film?

A

Optical clarity
Hydrophobic barriers (prevents overflow)
Slows down evaporation
Lubrication

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103
Q

What tri-laminar layer consists of electrolytes and proteins?

A

Middle, aqueous layer

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104
Q

The middle layer of the tear film is secreted by what 3 structures?

A

Main lacrimal glands

Accessory lacrimal glands of Wolffring and Krause

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105
Q

What is the 4 functions of the middle, aqueous layer of the tear film?

A

Supplies oxygen
Antibacterial
Smoothens minor irregularities
Washes away debris

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106
Q

What cells/structures do the posterior, glycoprotein layer is secreted?

A

Conjunctival goblet cells

Accessory lacrimal glans of Henle and Manz

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107
Q

What characteristic of the posterior, glycoprotein layer allows better stability of the tear film layer?

A

Lowers surface tension

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108
Q

What tri-laminar layer converts the epithelium from hypdrophobic to hydrophilic which allows for even distribution of tears?

A

Posterior, glycoprotein layer

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109
Q

What are the 4 recti muscles?

A

Superior rectus
Inferior rectus
Medial rectus
Lateral rectus

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110
Q

What are the 2 oblique muscles?

A

Superior oblique

Inferior oblique

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111
Q

Origin, insertion, blood supply and size of medial rectus

A

Origin - annulus of zinn
Insertion - medially, 5.5 mm from limbus
Blood supply - inferior muscular branch of ophthalmic artery
Size - 40.8 mm long, 1.3 mm wide

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112
Q

Origin, insertion, blood supply and size of inferior rectus

A

Origin - annulus of zinn
Insertion - inferiorly, 6.5 mm from limbus
Blood supply - inferior muscular branch of ophthalmic artery and infraorbital artery
Size - 40 mm long, 9.8 mm wide

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113
Q

Origin, insertion, blood supply and size of lateral rectus

A

Origin - annulus of zinn
Insertion - laterally, 6.9 mm from limbus
Blood supply - lacrimal artery
Size - 40.6 mm long, 9.2 mm wide

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114
Q

Origin, insertion, blood supply and size of superior rectus

A

Origin - annulus of zinn
Insertion - superiorly, 7.7 mm from limbus
Blood supply - superior muscular branch of ophthalmic artery
Size - 41.8 mm long, 10.6 mm wide

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115
Q

Origin, insertion, blood supply and size of superior oblique

A

Origin - annulus of zinn
Insertion - to trochlear at orbital rim, then inferior and under superior rectus
Blood supply - superior muscular branch of ophthalmic artery
Size - 40.0 mm long, 10.8 mm wide

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116
Q

Origin, insertion, blood supply and size of inferior oblique

A

Origin - orbital floor
Insertion - posterior, inferior temporal quadrant at the level of the macula
Blood supply - inferior branch of ophthalmic and infraorbital artery
Size - 37 mm long, 9.6 mm wide

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117
Q

What is the blood supply of the extraocular muscles?

A

Muscular branches of the ophthalmic artery

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118
Q

What is blood supply of the lateral rectus?

A

Lacrimal artery

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119
Q

What is the blood supply of the inferior oblique?

A

Infraorbital artery

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120
Q

What structures do the CN III innervates?

A

Superior, medial, inferior rectus muscles and the inferior oblique

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121
Q

What structures do CN IV innervates?

A

Superior oblique

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122
Q

What structures do the CN VI innervates?

A

Lateral rectus

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123
Q

What is this thin, transparent vascular tissue?

A

Conjunctiva

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124
Q

What are the 3 zones of the conjunctiva?

A

Palpebral conjunctiva
Bulbar conjunctiva
Forniceal conjunctiva

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125
Q

What zone of the conjunctiva lines the inner aspect of the eyelids?

A

Palpebral conjunctiva

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126
Q

What zone of the conjunctiva covers the sclera?

A

Bulbar conjunctiva

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127
Q

What zone of the conjunctiva is where the fornix (junction of the palpebral and bulbar conjunctiva) located?

A

Forniceal conjunctiva

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128
Q

What is the vascular supply of the conjunctiva?

A

Anterior ciliary artery

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129
Q

What nerve innervates the conjunctiva?

A

1st division of CN V (ophthalmic division)

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130
Q

What are the 2 structures of the conjunctiva?

A

Conjunctival epithelium

Conjunctival stroma

131
Q

Describe the layer and epithelial lining of the conjunctival epithelium

A

2-5 layers of stratified columnar epithelial cells

132
Q

What cells of the conjunctival epithelium contains mucous secreting Goblet cells?

A

Superficial epithelial cells

133
Q

What cells of the conjunctival epithelium contains pigment?

A

Basal epithelial cells

134
Q

What are the layers of the conjunctival stroma?

A

Adenoid layer

Fibrous layer

135
Q

What layer of the conjunctival stroma that consists of the lymphoid tissue and dose not develop until 2nd or 3rd month of life?

A

Adenoid layer

136
Q

What layer of the conjunctival stroma that contains connective tissue?

A

Fibrous layer

137
Q

Where is the accessory lacrimal glands mostly found?

A

Lower fornix

138
Q

What structure is a fibrous membrane that envelops the eye from limbus to the optic nerve?

A

Tenon’s capsule

139
Q

Tenon’s capsule contributes to what ligament?

A

Check ligaments

140
Q

The tenon’s capsule forms what ligament?

A

Lockwood ligament

141
Q

Describe the contributions of the tenon’s capsule to the check ligament

A

Tubular reflections of the tenon’s capsule over the EOM’s

Limits action of the EOM’s

142
Q

Describe how the tenon’s capsule forms the lookwood’s ligament

A

Suspensory ligament of the globe

Formed by the fusion of the tenon’s with the fascia of the inferior rectus and the inferior oblique

143
Q

What structure is a fine, thin, elastic layer which covers the sclera?

A

Episclera

144
Q

What structure contains numerous blood vessels which provides nourishment for the sclera?

A

Episclera

145
Q

What is the thick outer coat of the eye?

A

Sclera

146
Q

Normally, what is the characteristics of the sclera?

A

White and opaque

147
Q

What structure becomes red and in inflammatory and infectious conditions?

A

Sclera

148
Q

What structure is avascular, fibrous, outer, protective coating of the eye?

A

Sclera

149
Q

Describe the course of the sclera anteriorly and posteriorly

A

Continuous with the cornea anteriorly and with the dural sheath posteriorly

150
Q

What structure is scleral fibers that pass through e optic nerve and acts like a sieve?

A

Lamina cribosa

151
Q

What is the thickness of the sclera where the EOM’s insert and elsewhere?

A

0.3 mm thick where the EOM’s insert and about 1 mm thick elsewhere

152
Q

The sclera is composed of what cells/substances?

A

Bundles of collagen, fibroblasts and ground substance

Unlike cornea, contains more water and fibers are less uniformly arranged

153
Q

What is the transparent front “window” of the eye?

A

Cornea

154
Q

What is considered to be the major refractive surface of the eye?

A

Cornea

155
Q

What structure loss of transparency in infectious and inflammatory diseases?

A

Cornea

156
Q

Why is that cornea is considered to be the main refractive element of the eye (43D)?

A

More curved posteriorly than anteriorly

157
Q

Cornea’s transparency is secondary to what 3 characteristics?

A

Uniform structure
Avascularity
Deturgescence

158
Q

Describe the 3 dimensions of an average adult cornea

A
  1. 54 mm at the center (more spherical in shape)
  2. 65 mm at the periphery (flatter)
  3. 5 mm in diameter
159
Q

What are the 5 layers of the cornea?

A 
Epithelium
Bowman's membrane
Stroma
Descemet's membrane
Endothelium
160
Q

Cornea is nourished by what 2 structures?

A

Precorneal tear film layer which provides oxygen to the epithelium
Aqueous humor which provides glucose to the stroma and epithelium

161
Q

How many layers of the corneal epithelium?

A

5-6 layers

162
Q

What 3 type of cells that are found in the corneal epithelium?

A

Basal columnar cells
Polygonal cells (“wing cells”)
Nonkeratinized stratified squamous cells from the superficial layer

163
Q

What cells are also known as “wing cells”?

A

Polygonal cells

164
Q

What cells in the corneal epithelium is present in the superficial layer?

A

Nonkeratinized stratified squamous cells

165
Q

The corneal epithelium is attached by what structures?

A

Hemidesmosomes

166
Q

What is the characteristic of the cornea epithelium that is due to its lipid content?

A

Hydrophobic

167
Q

What structure of the cornea that is acellular, therefore, cannot regenerate after injury?

A

Bowman’s membrane/layer

168
Q

What structure of the cornea that opacifies or forms a scar after injury?

A

Bowman’s membrane/layer

169
Q

What structure of the cornea serves as a barrier to most molecules?

A

Bowman’s membrane/layer

170
Q

What structure of the cornea contributes to 90% of the corneal thickness?

A

Stroma

171
Q

What cells/substances composed the cornea that makes it optically clear?

A

Fibroblasts (keratinocytes)

Ground substance and collagen lamellae (uniformly arranged and avascular)

172
Q

What is the characteristic of the stroma in the cornea that allows for its optical clarity?

A

Regular arrangement of the collagen fibers in the stroma

173
Q

How many percentage of the light that is transmitted by the cornea?

A

98%

174
Q

What structure of the cornea known to be the basement membrane of the corneal endothelium?

A

Descemet’s membrane

175
Q

What are the metabolic by-products of the Descemet’s membrane and peripherally located?

A

Hassal-Henle bodies

176
Q

What is the central excresences of the cornea which look like bubbles in the central cornea?

A

Corneal Guttata

177
Q

What happens in Fuch’s Endothelial Dystrophy?

A

Endothelial cell loss leading to loss of visual acuity

178
Q

What is the embryonal origin of the corneal epithelium?

A

Neural crest (neuroectodermal in origin)

179
Q

The corneal endothelium is composed of how many layer and what type of cells?

A

Single layer of hexagonal cells

180
Q

The apex of the corneal endothelium faces what structures?

A

Anterior chamber

181
Q

The base of the corneal endothelium is attached to what structure?

A

Descemet’s membrane

182
Q

How many hexagonal cells in the corneal endothelium are diminished as we age?

A

1 million cells at birth

183
Q

What are the 2 functions of the corneal endothelium?

A

Barrier between the stroma and the aqueous

Pump to maintain the cornea in a partially dehydrated state

184
Q

What are the 3 fates of the corneal endothelium when subjected to injury from either surgery, raised IOP or disease?

A

Corneal decompensation
Edema
Clouding of the cornea

185
Q

What is the junction between the cornea and sclera?

A

Limbus

186
Q

What condition is the whitening of the limbus as part of old age?

A

Arcus senilis

187
Q

What condition is often mistaken as cataract?

A

Arcu senilis

188
Q

What is the importance of the limbus?

A

Surgical landmark

189
Q

What are the 5 structures that are included in the limbus?

A 
Conjunctiva
Tenon's capsule
Episclera
Corneoscleral stroma
Aqueous outflow apparatus
190
Q

What are the 10 internal ocular structures?

A 
Anterior chamber 
Iris
Lens
Ciliary body
Posterior chamber
Vitreous cavity
Retina
Macula
Choroid 
Optic disc
191
Q

What is the space between the cornea and iris?

A

Anterior chamber

192
Q

What is the watery fluid found in the anterior chamber?

A

Aqueous humor

193
Q

Normally, is the anterior chamber cellular or acellular?

A

Acellular

194
Q

Presence of cells in the anterior chamber indicates what conditions?

A

Infectious

Inflammatory

195
Q

What are the 5 important structures of the anterior chamber?

A 
Schwalbe's line
Schlemn's canal and the trabecular meshwork
Scleral spur
Anterior border of the ciliary body
Iris
196
Q

What structure of the anterior chamber that marks the termination of the corneal endothelium?

A

Schwalbe’s line

197
Q

What structure drains the aqueous from the anterior chamber?

A

Schlemn’s canal and the trabecular meshwork

198
Q

What structure of the anterior chamber that has inward extension of the sclera between the ciliary body and Schlemn’s canal?

A

Sclera spur

199
Q

What structure of the anterior chamber is the iris and ciliary body attached?

A

Scleral spur

200
Q

What is the middle, vascular layer of the eye?

A

Uveal tract

201
Q

What structure contributes to the blood supply of the retina?

A

Uveal tract

202
Q

What 3 structures comprise the uveal tract?

A

Iris
Ciliary body
Choroid

203
Q

What structure is the anterior extension of the ciliary body?

A

Iris

204
Q

What is the colored part of the eye that screens the light?

A

Iris

205
Q

What structure is the pigmented posterior surface?

A

Iris

206
Q

What structure accounts for the variety of eye colors seen?

A

Iris

207
Q

The variety of colors seen by the iris is dependent on the amount of what substance?

A

Pigment

208
Q

The iris is composed of:

A

Blood vessels
Connective tissue
Melanocytes
Pigment cells

209
Q

What 2 muscles are found in the iris stroma?

A

Dilator muscle

Sphincter muscle

210
Q

Dilation of the pupillary size is due to the sympathetic or parasympathetic activity?

A

Sympathetic activity

211
Q

Constriction of the pupils is due to sympathetic or parasympathetic activity?

A

Parasympathetic activity

212
Q

What cranial nerve is responsible in constricting the pupils?

A

CN III

213
Q

What is the blood supply of the iris?

A

Major circle of the iris

214
Q

Describe the major circle of the iris

A

Non-fenestrated endothelium (do not leak flourescein on angiography)

215
Q

What is the sensory innervation of the iris?

A

Ciliary nerves

216
Q

What is the circular opening at the center of the iris?

A

Pupil

217
Q

What structure adjusts the amount of light entering the eye?

A

Pupil

218
Q

What determines the size of the pupils?

A

Parasympathetic and sympathetic innervation of the iris

219
Q

What structure of the eye that produces the aqueous humor?

A

Ciliary body

220
Q

What happens with accommodation?

A

Changes in tension leading to increased thickness of the lens

221
Q

Describe accommodation

A

Allows eye to focus at near objects

222
Q

What structure extends from the anterior end of the choroid to the root of the iris (6 mm)?

A

Ciliary body

223
Q

What are the 2 parts of the ciliary body?

A

Pars plicata

Para plana

224
Q

What is the part of the ciliary body that is the anterior corrugated zone?

A

Par plicata

225
Q

What structure of the pars plicata that produces the aqueous humor?

A

Ciliary processes

226
Q

What part of the ciliary body that is flattened, posterior zone?

A

Pars plana

227
Q

The ciliary body is lined by what 2 layers?

A

Internal non-pigmented layer

External pigmented layer

228
Q

What lining of the ciliary body that represents the anterior extension of the neuroretina?

A

Internal non-pigmented layer

229
Q

What lining of the ciliary body that represents the extension of the retinal pigment epithelium?

A

External pigmented layer

230
Q

What structure of the ciliary body that composed of longitudinal, circular and radial muscles?

A

Ciliary muscle

231
Q

What structure of the ciliary body that contracts and relaxes the zonular fibers?

A

Circular muscles

232
Q

What 2 events happen when the circular muscle is stimulated?

A

Alters the tension on the capsule of the lens

Allows the lens to give variable focus for distance and near

233
Q

What structure of the ciliary body that inserts into the trabecular meshwork (to vary pore size)?

A

Longitudinal muscles

234
Q

What is the vascular, pigmented layer between the sclera externally and retina internally?

A

Choroid

235
Q

What provides blood supply to the outer retinal layers?

A

Choroid

236
Q

What part of the retina is nourished by the choroid?

A

Outer retina

237
Q

What are the 3 layers of blood vessels of the choroid?

A

Innermost/choroicapillaries
Middle layer
Outer layer

238
Q

What layer of the choroid that has fenestrated characteristic?

A

Innermost/choroicapillaries

239
Q

What are the 3 blood supply of the choroid?

A

Long posterior ciliary arteries
Short posterior ciliary arteries
Recurrent branches of the anterior ciliary arteries

240
Q

What veins drain the choroid?

A

Vortex veins

241
Q

What structure of the choroid that is bound internally?

A

Bruch’s membrane

242
Q

What structure of the choroid that is bound externally?

A

Sclera

243
Q

What are the 5 elements of the Bruch’s membrane?

A

Basal lamina of the retinal pigment epithelium
Inner collagenous zone
Porous elastic fibers
Outer collagenous zone
Basal lamina of the outer layer of the choriocapillaries

244
Q

Defects of Bruch’s membrane may arise from what 4 possible conditions?

A

Myopia
Pseudoxanthoma elasticum
Trauma
Inflammation

245
Q

Defects of the Bruch’s membrane leads to the formation of what structure?

A

Formation of subretinal neovascular membrane

246
Q

What structure is bound externally by the choroid?

A

Sclera

247
Q

What is the space between the choroid and the sclera?

A

Suprachoroidal space

248
Q

What is the shape of the lens?

A

Biconvex

249
Q

What structure is second of 2 refractive elements?

A

Lens

250
Q

What structure is weaker than the cornea (1/3 of the total refractive power of the eye)?

A

Lens

251
Q

What is the measurement of the lens anterosterior and equatorial diameter?

A

Anteroposterior: 4.0 - 5.0 mm

Equatorial diameter: 9.0 - 10 mm

252
Q

What are the 3 compositions of the lens (with the percentage)?

A

65% water
35% protein (highest protein content of any tissue in the body)
Trace minerals (Na, Cl, K, ascorbic acid, glutathione)

253
Q

Lens thickness changes during what process?

A

Accommodation

254
Q

What are the 2 structures that nourish solely the lens?

A

Aqueous

Vitreous

255
Q

The lens is enclosed by what structure?

A

Capsule

256
Q

Describe the Capsule of the lens

A

Semi-permeable membrane
Product of the lens epithelium
Anterior capsule is 2x thicker than the posterior capsule

257
Q

What structure holds the lens in place?

A

Zonule of Zinn

258
Q

What does the Zonule of Zinn composed of?

A

Fibrils

259
Q

Where does the Zonule of Zinn arise from?

A

Ciliary body

260
Q

Where does the Zonule of Zinn inserts?

A

Lens equator

261
Q

What is the small space behind the iris and in front of the vitreous?

A

Posterior chamber

262
Q

The posterior chamber is filled with what fluid?

A

Aqueous humor

263
Q

The posterior chamber is normally cellular or acellular?

A

Acellular

264
Q

What is the large space behind the lens?

A

Vitreous cavity

265
Q

The vitreous cavity extends to what structure?

A

Retina

266
Q

What is the volume of vitreous cavity?

A

Approximately 4.5 cc

267
Q

Describe the vitreous humor

A

Transparent gel-like material

268
Q

What fluid is filled in the vitreous cavity?

A

Vitreous humor

269
Q

What are the characteristics of the vitreous?

A

Clear, avascular, gelatinous body
Comprises 2/3 of the volume of the eye
99% water, 1.0% collagen and hyaluronic acid
Involved in metabolism which is the passageway for metabolites used by the lens, ciliary body and retina

270
Q

What is the outer surface of the vitreous?

A

Hyaloid membrane

271
Q

The hyaloid membrane is in contact with what 5 structures?

A 
Posterior capsule
Zonules
Pars plana
Retina
Optic nerve head
272
Q

What structure is where the vitreous is firmly attached to the retina?

A

Vitreous base

273
Q

What condition involved in the separation of the vitreous from the inner retina?

A

Posterior vitreous detachment

274
Q

What condition is seen as a ring in the vitreous (examiner)?

A

Posterior vitreous detachment

275
Q

Is posterior retinal detachment occurs with age?

A

It occurs with age

276
Q

What condition is associated with posterior retinal detachment?

A

Posterior vitreous detachment

277
Q

What structure is thin, semitransparent, multilayer sheet of neural tissue lining the vitreous cavity?

A

Retina

278
Q

Retina ends at what structure?

A

Ora Serrata

279
Q

Retina is located how many millimeters behind the Schwalbe’s line temporally and nasally?

A
  1. 5 mm behind the Schwalbe’s line temporally

5. 7 mm nasally

280
Q

What is the thickness of the retina at the Ora and Posterior pole?

A
  1. 1 mm thick at the Ora

0. 23 mm thick at the posterior pole

281
Q

Retina is closely attached to what structure?

A

RPE

282
Q

Retina is related to what 3 structures?

A

Bruch’s membrane
Choroid
Sclera

283
Q

Retina is firmly attached at what 2 structures?

A

Optic disc

Ora serrata

284
Q

What are the 10 layers of the retina?

A 
Internal limiting membrane
Nerve fiber layer
Ganglion cell layer
Inner plexiform layer
Inner nuclear layer
Outer plexiform layer
Outer nuclear layer of photoreceptor nuclei
External limiting membrane
Layers of rods and cones
Retinal pigment epithelium
285
Q

What layer of the retina abuts the vitreous?

A

Internal limiting membrane

286
Q

What layer of the retina has axons of the ganglion cells?

A

Nerve fiber layer

287
Q

What layer of the retina that has axons of the bipolar and amacrine cells and dendrites of the ganglion cells and their synapses?

A

Inner plexiform layer

288
Q

What layer of the retina that has nuclei of bipolar, horizontal, Mueller and amacrine cells?

A

Inner nuclear layer

289
Q

What layer of the retina that is made up of the connections between photoreceptor synaptic bodies and the horizontal and bipolar cells?

A

Outer plexiform layer

290
Q

What layer of the retina that is thicker at the macula (layer of Henle)?

A

Outer plexiform layer

291
Q

What does the outer nuclear layer of photoreceptor nuclei contain?

A

Rods and cones

292
Q

What are the 8 functions of the retinal pigment epithelium?

A 
Vitamin A metabolism
Maintenance of the outer blood-retinal barrier
Phagocytosis of the photoreceptor outer segments
Absorption of light
Heat exchange
Formation of the basal lamina
Production of mucopolysaccharides
Active transport
293
Q

Describe the adjacent RPE cells in the retinal pigment epithelium

A

Attached to each other by junctional complexes which provide both structural and metabolic stability (outer retinal barrier)

-zonula occludentes and zonula adherentes

294
Q

What structure is retinal pigment epithelium thickest and thinnest?

A

Thickest at the Papillomacular Bundle

Thinnest at the Fovea

295
Q

What is the area of the retina that is responsible for fine, central vision?

A

Macula

296
Q

What is the oval depression in the center of the macula?

A

Fovea

297
Q

Fovea is approximately how many diameters away from the optic disc?

A

2 disc diameter

298
Q

Fovea is slightly inferior to what structure?

A

Optic disc

299
Q

What reflex is the light reflection at fovea seen during ophthalmoscopy?

A

Foveal reflex

300
Q

Where is the macula located?

A

Area of the temporal vascular arcade

301
Q

What structure is where more than one layer of ganglion cell nuclei can be found?

A

Macula

302
Q

What is the thinnest outer nuclear layer?

A

Fovea

303
Q

How many millimeters in diameter is the fovea?

A

1.5 mm

304
Q

What pigment contains by the fovea?

A

Xanthophyll pigment

305
Q

What is the central depression within the fovea?

A

Foveola

306
Q

What 3 cells are present in foveola?

A

Photoreceptor cells (made up of cones)
Glial cells
Mueller cells

307
Q

What structure is responsible for the most acute vision?

A

Foveola

308
Q

What is known to be capillary-free zone?

A

Foveal Avascular Zone

309
Q

What is the important landmark for treatment of subretinal neovascular membrane?

A

Foveal Avascular Zone

310
Q

What nerve is not really a peripheral nerve and is actually a direct extension of the CNS?

A

Optic nerve

311
Q

What is the measurement of the optic nerve horizontally and vertically?

A
  1. 88 mm vertically

1. 77 mm horizontally

312
Q

What nerve corresponds to the “blind spot” perimetry?

A

Optic nerve

313
Q

How many axons do the optic nerve has?

A

1.2 million axons

314
Q

How long is the optic nerve?

A

50 mm long

315
Q

What are the 3 blood supply of the Circle of zinn-haller?

A

Short PCA
Choroidal circulation
Pial vasculature

316
Q

What are the 4 parts of the optic nerve?

A

Intra-ocular (optic nerve head)
Intra-orbital
Intra-osseous/intra-cannalicular
Intra-cranial

317
Q

What part of the optic nerve that is/has:

  • 1 mm long; 1.5 mm horizontally; 1.8 mm vertically
  • optic disc (visible by fundoscopy)
  • non-myelinated axons
A

Intra-ocular

318
Q

What part of the optic nerve that is/has:

  • 25 mm in length: 3-4.5 mm in diameter
  • lined by dura, arachnoid and pia mater
  • fuses at the apex of the orbit with periosteum and annulus of Zinn
A

Intra-orbital

319
Q

What part of the optic nerve that is/has:

  • 9 mm in length
  • bordered by the paranasal sinuses
  • firmly anchored to the bone
A

Intra-osseous/intra-canalicular

320
Q

What is the significance of firm anchorage of the intra-osseous/intra-canalicular to the bone?

A

A small mass lesion in the canal can cause compressive optic neuropathy even before it becomes radiological visible

321
Q

What part of the optic nerve that is/has:

  • 10 mm long, may vary from 3-16 mm
  • region where the carotid artery bifurcates into ACA and MCA
A

Intra-cranial

322
Q

What part of the optic nerve where the carotid artery bifurcates into ACA and MCA?

A

Intra-cranial

323
Q

What is the portion of the optic nerve visible within the eye?

A

Optic disc

324
Q

What structure is composed of axons whose cell bodies are located in the ganglion cell layer of the retina?

A

Optic disc

Ophthalmology (3 decks)

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