Anatomy And Physiology Of The Eye

Front 1

The visual system is housed within the____________?

Back 1

Bony Orbit

Front 2

Name the four walls of the bony orbit?

Back 2

Roof
Medial wall
Lateral wall
Floor

Front 3

Name the 5 accessory structures of the eye?

Back 3

Eyebrows
Eyelids (palpebrae)
Conjunctiva
Lacrimal apparatus
Extrinsic eye muscles

Front 4

What is the function of the eyebrows?

Back 4

To shade the eye and to prevent moisture (mostly perspiration) and rain, from flowing into the eye.

Front 5

What is the scientific name for the eyelids?

Back 5

Palpebrae

Front 6

What is the function of the palpebrae?

Back 6

To protect and moisten the eye.

Front 7

What is the function of the eyelashes?

Back 7

To protect the eye from debris and to provide a reflexive warning when objects near the eye. Eyelashes also aid in the secretion of lubricating sebum from the ciliary glands at their base.

Front 8

What are conjunctiva?

Back 8

Clear, epithelial, mucous membrane (cells and underlying basement membrane) that cover the sclera (white of the eye) and line the inside of the eyelids.

Front 9

Which conjunctiva covers the sclera?

Back 9

Bulbar conjuctiva

Front 10

Conjunctivitis can be cause by bacteria, allergies or viruses. Conjuctivitis in only one eye is generally associated with which of these causes?

Back 10

Bacterial infection

Front 11

What are caruncles?

Back 11

Small, red mound of tissue in the medial corner of the eye that contains modified sebaceous (oil) and sweat glands.

Front 12

Which muscle keeps the eyelid raised?

Back 12

Levator palpebrae superioris

Front 13

Which muscle closes the eyelids?

Back 13

Orbicularis oculi

Front 14

Modified oil glands producing secretions that keep the inner eyelid lubricated are________?

Back 14

Tarsal glands

Front 15

Tarsal glands are embedded within the ___________?

Back 15

Tarsal plate

Front 16

Styes are inflammation of the ciliary glands at the base of the eyelids. What are chalazions.

Back 16

Inflammation of blocked tarsal glands, usually on the upper eyelid.

Front 17

What is the physiologic system containing the orbital structures for tear production and drainage?

Back 17

Lacrimal apparatus

Front 18

Liquid tears are secreted from the lacrimal gland. What are the main components of tears?

Back 18

Water, salts, mucus, lysozyme

Front 19

Lacrimal glands are located in the ______________________?

Back 19

The upper, outer portion of each orbit.

Front 20

What is the function of lysozynmes in tears?

Back 20

To lyse bacteria, thus serving as inate antibiotics.

Front 21

Tears first drain into the _____________, then enter the ___________ before draining into the _______ and nasal cavity via the naslacranial duct.

Back 21

Puncta → Lacrimal canaliculi → Lacrimal sac → Nasolacrimal duct → Nasal cavity

Front 22

Reflex tearing, as in response to eye irritants, is a sensory response controlled by the 5th (trigeminal) cranial nerve. Which nerve controls the parasympathetic motor pathway that results in emotional tearing or “crying”?

Back 22

The 7th (facial) cranial nerve

Front 23

The parasympathetic branch of the autonomic system controls the lacrimal glands via the neurotransmitter acetylcholine, through both the nicotinic and muscarinic receptors. Which receptor(s) are involved in lacrimal secretion due to fight-or-flight stimuli?

Back 23

α1-receptors

Front 24

Which drug would produce more lacrimal secretions, amitriptyline or pilocarpine?

Back 24

Pilocarpine

Front 25

Name the six extrinsic eye muscles

Back 25

Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Superior oblique
Inferior oblique

Front 26

Four of the six extrinsic eye muscles are innervated by the oculomotor (3rd cranial) nerve. Name these four extrinsic eye muscles.

Back 26

Superior rectus
Inferior rectus
Medial rectus
Inferior oblique

Front 27

Name the condition in which the eyes will not align properly?

Back 27

Strabismus

Front 28

Double vision is also known as?

Back 28

Diplopia

Front 29

Name the three layers of the outer wall of the eyeball starting from the outermost layer.

Back 29

Sclera
Choroid (uvea)
Retina

Front 30

Which layer of the eyball is the vascular layer?

Back 30

Choroid (uvea) layer

Front 31

Which layer of the eyeball is the is the neural layer?

Back 31

Retina

Front 32

The sclera is also known as the ________ layer.

Back 32

Fibrous layer

Front 33

Transparent front (anterior) portion of the fibrous layer that covers the iris, pupil, and anterior chamber?

Back 33

Cornea

Front 34

Protects and provides shape to the inner structures of the eyeball?

Back 34

Sclera

Front 35

Anchoring site for the six extrinsic eye muscles?

Back 35

Sclera

Front 36

The sclera is mainly comprised of ______ _______ fibers.

Back 36

Dense collagen fibers

Front 37

Light first enters the eye through the cornea. The cornea is avascular, true or false?

Back 37

True

Front 38

Name the five layers of the cornea?

Back 38

Corneal epithelium
Bowman's layer
Corneal stroma
Descemet's membrane
Corneal endothelium

Front 39

Thick, transparent layer consisting of regularly-arranged collagen fibers along with sparsely populated keratocytes. Consists of approximately 200 layers of type I collagen fibrils and forms 90% of the corneal thickness and serves as hydrophilic barrier.

Back 39

Corneal stroma

Front 40

Thin, acellular layer that serves as the modified basement membrane of the corneal endothelium.

Back 40

Descemet's membrane

Front 41

Tough layer that protects the corneal stroma, consisting of irregularly-arranged collagen fibers.

Back 41

Bowman's layer

Front 42

Simple squamous or low cuboidal monolayer of mitochondria-rich cells responsible for regulating fluid and solute transport between the aqueous and corneal stromal compartments. Also forms lipophilic barrier.

Back 42

Corneal endothelium

Front 43

Air-tear film interface, the most significant component of the total refractive power of the eye. Also resistant to lypophilic drugs?

Back 43

Corneal epithelium

Front 44

Posterior portion of the vascular layer of the eye that provides nutrients to the inner structures of the eye? Highly pigmented, this structure absorbs light and prevents light from scattering.

Back 44

Choroid

Front 45

Anterior portion of the vascular layer of the eye?

Back 45

Ciliary body

Front 46

Name the three structures of the ciliary body?

Back 46

Ciliary processes
Ciliary zonule/suspensory ligaments
Ciliary muscles

Front 47

Holds the lens in place?

Back 47

Ciliary zonule/suspensory ligaments

Front 48

Complex of vasculature and epithelium responsible for producing and secreting aqueous humor?

Back 48

Ciliary processes

Front 49

Controls the shape of the lens?

Back 49

Ciliary muscles

Front 50

Other structure of the vascular layer of the eye that is continuous with the ciliary body and is located between the cornea and lens?

Back 50

Iris

Front 51

Contracts and expands in response to circular and radial muscles to make the pupil larger or smaller?

Back 51

Iris

Front 52

Constricts the pupil (miosis) in response to bright light and close vision? Under parasympathetic control.

Back 52

Circular muscles/sphincter pupillae

Front 53

Pigmented structure that colors the eye?

Back 53

Iris

Front 54

Dilates the pupils (mydriasis) in response to dim light and distant vision? Under sympathetic control.

Back 54

Radial muscles/dilator pupillae

Front 55

Name the two layers of the retina?

Back 55

Pigmented layer and neural layer

Front 56

Retinal layer involved in photo-transduction (actual vision)?

Back 56

Neural layer

Front 57

What are the three main functions of the pigmented layer of the retina?

Back 57

Single cell layer that absorbs light and prevents scattering
Removes old photoreceptor cells and provides local storage of vitamin-A.

Front 58

Structure that divides the anterior segment from the posterior segment of the eye?

Back 58

Lens

Front 59

Two divisions of the anterior segment of the eye?

Back 59

Anterior and posterior chambers

Front 60

The bulk of the lens is made up of _______?

Back 60

-Lens fibers
-No nuclei, few organelles
-Crystallins: transparent, folded proteins that form body of lens

Front 61

Cuboidal cells on anterior lens surface that differentiate into lens fibers?

Back 61

Lens epithelium

Front 62

Clouding of the lens caused by clumping of crystallins?

Back 62

Cataracts

Front 63

Cause of cataracts?

Back 63

Inadequate delivery of nutrients to deeper lens fibers

Front 64

Aqueous humor produced by the ciliary body is circulated through the posterior chamber of the anterior segment and enters the anterior chamber through the pupil. Where does this aqueous humor drain?

Back 64

Through the scleral venous sinus (Canal of Schlemm).

Front 65

Purpose of aqueous humor?

Back 65

To supply oxygen and nutrients to the anterior portion of the eye and to transport metabolic waste away from the eye.

Front 66

What substance is responsible for maintaining intraocular pressure in the eye?

Back 66

Aqueous humor

Front 67

Blocked drainage of aqueous humor causes intraocular pressure to rise, compressing the retina and optic nerve. This can lead to __________.

Back 67

Glaucoma

Front 68

Gel like substance that fills the posterior portion of the eye?

Back 68

Vitreous humor

Front 69

Function of vitreous humor?

Back 69

To maintain the global shape of the eyeball and to hold the neural layer of the retina against the pigmented layer of the retina.

Front 70

The spectrum of visible light is?

Back 70

400-700 nm

Front 71

Photoreceptors absorb different wavelengths of light. Cone cells absorb light from blue (420 nm) to green (530 nm) to red (560 nm). What is the color and wavelength of light absorbed by rod shaped cells?

Back 71

Green at 500 nm

Front 72

Which type of photoreceptor cell provides low light and peripheral vision?

Back 72

Rods

Front 73

Which type of photoreceptor cells are most prevalent in the eye?

Back 73

Rods

Front 74

Cone shaped photoreceptor cells are specialized for?

Back 74

Color vision and high visual acuity

Front 75

Which cells transmit signals from the photoreceptors to the ganglion cells?

Back 75

Bipolar cells

Front 76

Ganglion cells are attached to the __________.

Back 76

Optic nerve

Front 77

Which cells in the eye are responsible for action potentials?

Back 77

Ganglion cells

Front 78

There are two type of interneurons dispersed throughout the neural layer of the eye. Name these interneurons?

Back 78

Horizontal cells and amacrine cells

Front 79

What is the function of interneurons in the neural layer of the eye?

Back 79

To modify signals going to the bipolar and ganlgion cells

Front 80

What is the function of the horizontal cells in the neural layer of the eye?

Back 80

To synapse with photoreceptors and bipolar cells

Front 81

What is the function of the amacrine cells in the neural layer of the eye?

Back 81

To synapse with bipolar and ganglion cells

Front 82

Name the structure in the neural layer of the eye where the optic nerve leaves the eye.

Back 82

Optic disk

Front 83

The optic disk is also known as the?

Back 83

Blind spot

Front 84

Where does the vasculature enter the eye?

Back 84

Through the optic disk

Front 85

Which blood vessels supply the outer third of the eye?

Back 85

Choroid vessels

Front 86

Which blood vessels supply the inner two thirds of the eye?

Back 86

Central artery and central vein of the retina

Front 87

Lateral to the optic disc is an area that contains mostly cones. Within this area is a small groove called the Fovea Centralis that contains only cones. Name this structure.

Back 87

Macula lutea

Front 88

Any visual image requiring high accuity is focused onto the _____________.

Back 88

Fovea centralis

Front 89

Name the four main segments of photoreceptor cells.

Back 89

Outer segment
Inner segment
Cell body
Inner fiber

Front 90

Which segment of photoreceptor cells contains the receptor region?

Back 90

Outer segment

Front 91

Which segment of photoreceptor cells contains the pigment and changes shape when light is absorbed?

Back 91

Outer segment

Front 92

In which type of photoreceptor cell is the Inner segment directly connected to the cell body?

Back 92

Cones

Front 93

Which type of photoreceptor cell has an outer fiber

Back 93

Rods have outer fibers

Front 94

Rods and cones both contain a visual pigment. What is the pigment in rod cells?

Back 94

Rhodopsin

Front 95

Name the two main components of rhodopsin?

Back 95

Retinal and opsin

Front 96

Which rhodopsin component determines the wavelength of light absorbed and involves a conformational change that causes the activation of the phototransduction cascade?

Back 96

Opsin

Front 97

The absorption of a photon of light results in the photoisomerisation of ______________?

Back 97

Retinal (11-cis retinal to all-trans retinal)

Front 98

Which comes first, photoisomerization of retinal or the conformational change of opsin?

Back 98

Photoisomerization of retinal

Front 99

What other term is used to describe photoisomerization of retinal?

Back 99

Bleaching of retinal

Front 100

In which segment of photoreceptor cells are the cation channels located?

Back 100

Outer segment

Front 101

The cation channels are open in the dark or in the presence of light?

Back 101

In the dark

Front 102

What happens when light is absorbed and 11-cis retinal is converted to trans-retinal?

Back 102

The G-protein, transducin, becomes activated

Front 103

Transducin activates phosphodiesterase (PDE) and PDE converts cGMP into GMP, closing the Na+ and Ca+ cation channels. What is the result of closing the cation channels?

Back 103

Hyperpolorization

Front 104

How can hyperpolorization lead to an action potential?

Back 104

Hyperpolorization of the photoreceptor cells halts glutamate release at the synapse with the bipolar cell. Glutamate is inhibitory in this mechanism.

Front 105

How does the halting of glutamate release from the photoreceptor cell depolorize the bipolar cell?

Back 105

Inhibitory glutamate is no longer available to block calcium release in the bipolar cell and calcium release in the bipolar cell leads to the release of excitatory glutamate at the synapse between the bipolar cell and the ganglion.

Front 106

The process is the same for cones except the visual pigment is ______________ instead of rhodpsin.

Back 106

Iodopsin