Eye and vision

Question 1

What meninge are the sclera and cornea derived from?

Answer 1

Dura mater

Question 2

What meninge is the choroid of the eye derived from?

Answer 2

Arachnoid mater

Question 3

What is the retina derived from?

Answer 3

Extension of the brain

Question 4

What are the symptoms of Horner’s syndrome?

Answer 4

Ptosis
Miosis
Anhidrosis of forehead
Flushing

Question 5

What forms the outer fibrous layer of the eye?

Answer 5

Cornea
Sclera

Question 6

What forms the middle vascular layer of the eye?

Answer 6

Choroid
Contains ciliary body and iris

Question 7

What forms the inner layer of the eye?

Answer 7

Retina
Contains sphincter and dilator pupillae

Question 8

What are the layers of the retina from internal to external?

Answer 8

Inner limiting membrane
Nerve fiber layer
Ganglion cell layer
Inner plexiform layer
Inner nuclear layer
Outer plexiform layer
Outer nuclear layer
Outer limiting membrane
Photoreceptor outer segment
Retinal pigment epithelium

Question 9

What separates the choroid from the retina?

Answer 9

Bruch’s membrane

Question 10

What are rods and cones?

Answer 10

Photoreceptors

Question 11

What composes the outer segments of the rods and cones?

Answer 11

Modified cilia made of stacks of flattened saccules or membranous disks

Question 12

Where is the photosensitive compound in rods and cones located?

Answer 12

Outer segment in the saccules and disks

Question 13

What part of the retina renews the rods and cones?

Answer 13

Pigment epithelium

Question 14

What prevent the reflection of rays back through the retina?

Answer 14

Extra melanin in the pigment epithelium absorbs extra light

Question 15

What is the likely inheritance of retinitis pigmentosa?

Answer 15

Autosomal recessive

Question 16

What is retinitis pigmentosa?

Answer 16

Phagocytic process is defective leading to a build up of debris causing blindness

Question 17

What is the blood supply of the receptors in the retina?

Answer 17

Mostly from capillary plexus in the choroid

Question 18

What is the fovea?

Answer 18

In center of macula
Densely filled cones and without rods

Question 19

What photoreceptor is more effective in low light intensity?

Answer 19

Rods

Question 20

What photoreceptor can detect a broader range of wavelengths?

Answer 20

Rods

Question 21

What photoreceptor passes information as a group to a single nerve fiber?

Answer 21

Rods

Question 22

What photoreceptor is more sensitive to movement?

Answer 22

Rods

Question 23

What photoreceptor responds more slowly to light?

Answer 23

Rods

Question 24

What is the pigment found in rods called?

Answer 24

Rhodopsin

Question 25

What photoreceptor is more numerous?

Answer 25

Rods

Question 26

What photoreceptor is more effective in high light intensity?

Answer 26

Cones

Question 27

What photoreceptor is sensitive to a specific color/wavelength?

Answer 27

Cones

Question 28

What photoreceptor acts individually on a single nerve fiber?

Answer 28

Cones

Question 29

What photoreceptor is for sharpness, gives a higher visual acuity?

Answer 29

Cones

Question 30

What photoreceptor responds more rapidly to light?

Answer 30

Cones

Question 31

What pigment is contained in cones?

Answer 31

Iodopsin

Question 32

What retinal layer does convergence mostly occur in?

Answer 32

Inner synaptic/plexiform layer

Question 33

What is the response of bipolar cells in the eye?

Answer 33

Generate relatively steady hyperpolarization or depolarization

Question 34

What is the response of horizontal cells in the retina?

Answer 34

Enhances brightness contrast to produce a sharper image

Question 35

What is the function of amacrine cells in the retina?

Answer 35

Record changes in illumination

Question 36

What vitamin is needed in the retina?

Answer 36

Vitamin A

Question 37

What is a deficiency in vit A cause?

Answer 37

Night blindness Follicular hyperkeratinosis Susceptibility to infection Cancer Anemia

Question 38

What pathway is vit A used for in the eye?

Answer 38

Regeneration of rhodopsin

Question 39

What is xerophthalmia?

Answer 39

Progressive keratinization of cornea leading to deterioration of eye tissue

Question 40

What causes xerophthalmia and keratomalacia?

Answer 40

Prolonged deficiency of vit A

Question 41

What is keratomalacia?

Answer 41

Wrinkling, progressive cloudiness, and increasing softening and ulceration of the corneas

Question 42

What are bitot spots?

Answer 42

Dry, silver-gray, triangular deposits on conjunctiva

Question 43

What photoreceptor is for color vision?

Answer 43

Cones

Question 44

What is scotopic vision?

Answer 44

Dark-adapted system that operates at low levels of illumination

Question 45

What is photopic vision?

Answer 45

Light-adapted system that operates at high levels of illumination

Question 46

What is the Purkinje shift?

Answer 46

Shifting from photopic to scotopic vision

Question 47

What is the inheritance for color blindness?

Answer 47

X-linked recessive

Question 48

What are the three types of cones?

Answer 48

S - blue M - green L - red

Question 49

What is the pupillodilator reflex?

Answer 49

Pupil dilates in response to emotion that activates the SyNS

Question 50

What is the course of the pupillodilator reflex?

Answer 50

Through posterior hypothalamus through brainstem to preganglionic sympathetic neurons in the lateral horn of spinal cord at T1 and then to the superior cervical ganglion at the base of the skull and then to the ophthalmic division of CN V

Question 51

What are the afferent components of the pupillary light reflex?

Answer 51

Photoreceptors Optic N Optic chiasma Optic tract Pretectal nucleus in midbrain

Question 52

What is the efferent pathway of the pupillary light reflex?

Answer 52

Edinger-Westphal nucleus Oculomotor N Ciliary ganglion Short ciliary N Sphincter pupillae

Question 53

What is accommodation as it relates to vision?

Answer 53

Process by which the eye adjusts the shape of the lens to keep objects in focus

Question 54

What is presbyopia?

Answer 54

Normal distance vision, but accommodation is reduced with age

Question 55

What is Marcus Gunn pupil?

Answer 55

Consensual light response normal in unaffected eye Eye dilates in when light is shown in affected eye

Question 56

What is Argyll Robertson Pupil?

Answer 56

Accommodation reflex present Pupillary light reflex absent Caused by neurosyphilis

Question 57

What are the afferents and efferents of the corneal reflex?

Answer 57

Aff - CN V Eff - CN VII

Question 58

What is the reason for macular sparing?

Answer 58

Larger representation for macula in the visual cortex

Question 59

What extra-ocular muscle is innervated by the abducens N?

Answer 59

Lateral rectus

Question 60

What extraocular muscle is innervated by the trochlear N?

Answer 60

Superior oblique

Question 61

What extraocular muscles are innervated by the oculomotor N?

Answer 61

Medial rectus Superior rectus Inferior rectus Inferior oblique

Question 62

Where is the horizontal gaze center?

Answer 62

Paramedian pontine reticular formation in the pons

Question 63

Where is the vertical gaze center located?

Answer 63

Rostral midbrain reticular formation

Question 64

What are the conjugate eye movements?

Answer 64

Saccades Smooth pursuit movements Vestibulo-ocular movements Optokinetic nystagmus

Question 65

What are the disconjugate eye movements?

Answer 65

Convergence Divergence

Question 66

What are saccades?

Answer 66

Rapid, ballistic movements of the eyes that abruptly change the point of fixation

Question 67

What controls saccades?

Answer 67

Frontal eye field

Question 68

What is internuclear ophthalmoplegia/ophthalmoparesis?

Answer 68

Inability to perform conjugate lateral gaze due to damage of interneuron between CN VI and CN III (medial longitudinal fasciculus)

Question 69

What are signs of internuclear ophthalmoplegia?

Answer 69

Abducting eye displays nystagmus Convergence is normal