Ocular: Visual Pathways (scott)

Question 1

Rods are specialized for __________ light and __________ detection

Answer 1

Dim

Motion

Question 2

Cones are specialized for __________ vision.

Answer 2

Color (day-time vision)

Question 3

Where are cone photoreceptors most populated?

Answer 3

In the macula

Question 4

The fovea only contains ___________.

Answer 4

Cones

Question 5

The signal from photoreceptors are passed onto what cells?

Answer 5

Retinal interneurons - bipolar cells, amacrine cells, horizontal cells

Question 6

Bipolar cells receive inputs from ____________ and project to ___________ cells.

Answer 6

Photoreceptors and project to ganglion cells

Question 7

Horizontal cells are located between which two layers?

Answer 7

Receptor cell layer and the bipolar cell layer

Question 8

Amacrine cells are located between the ___________ layer and the __________ layer and modulate the activity there.

Answer 8

Bipolar cell layer and the ganglion cell layer

Question 9

How do retinal ganglion cells send their output signal and to where?

Answer 9

Send output via axons that form the optic nerve to communicate with the brain

Question 10

Papillomacular Bundle is defined as:

Answer 10

Axons of the retinal ganglion cells coursing from the macula towards the optic disc

Question 11

What side of the optic disc does the papillomacular bundle enter into?

Answer 11

Temporal side of the optic disc

Question 12

Where are macular fibers situated within the retrobulbar optic nerve?

Answer 12

Centrally

Question 13

When do optic nerve fibers become myelinated?

Answer 13

After they exit the eye

Question 14

90% of the optic nerve fibers synapse where?

Answer 14

LGN

Question 15

10% of optic nerve fibers will project to the ____________ nucleus.

Answer 15

Suprachiasmatic nucleus

Question 16

Where is the optic chiasm located in relation to the 3rd ventricle?

Answer 16

Floor of 3rd ventricle

Question 17

At what structure/area does the visual information from right and left eyes cross to the contralateral side of the visual system?

Answer 17

Optic chiasm

Question 18

Posterior to the optic chiasm, the visual pathway continues on each side as an ____________.

Answer 18

Optic tract

Question 19

The nasal retinal fibers will cross at the _________.

Answer 19

Chiasm

Question 20

How do temporal retinal fibers course?

Answer 20

Remain Ipsilateral and do not cross over

Question 21

How can a pituitary adenoma impact visual fields?

Answer 21

Compress optic chiasm and cause bitemporal hemianopia

Question 22

An early stage pituitary adenoma will first compress the _____________ retinal fibers and manifest as a ______________________________.

Answer 22

First compress the inferonasal retinal fibers crossing in the chiasm

Manifest as a bitemporal superior quadrantanopia

Question 23

How might an aneurysm of the internal carotid artery impact visual fields?

Answer 23

By compressing temporal fibers of the optic chiasm, it is displaced and compressed against the contralateral ICA, which in turn compresses the temporal fibers on that same side and results in a rare binasal hemianopia

Question 24

Do afferent pupillomotor reflex fibers leave the optic tract before reaching the LGN?

Answer 24

Yes

Question 25

Where do afferent pupillomotor reflex fibers synapse?

Answer 25

Pretectal nucleus of the midbrain

Question 26

Each optic tract contains fibers from where?

Answer 26

Temporal retina of ipsilateral eye ## Footnote Nasal retinal fibers of the contralateral eye

Question 27

Temporal retinal fibers are carrying visual information regarding the __________ visual field.

Answer 27

Nasal visual field

Question 28

Nasal retinal fibers are carrying visual information regarding the ______________.

Answer 28

Temporal visual field

Question 29

Transection of the right optic tract would result in what deficit?

Answer 29

Left hemianopia

Question 30

The LGN is located in the _______ thalamus.

Answer 30

Lateral

Question 31

Visual information from the optic tracts is then relayed to their respective __________.

Answer 31

LGN

Question 32

LGN is a _______ layered structure.

Answer 32

6

Question 33

The axons exiting the LGN are known as the _______________.

Answer 33

Optic radiations

Question 34

Some of the inferior fibers of the optic radiation will loop into the __________ lobe on their way to __________ and are collectively known as ______________.

Answer 34

Temporal lobe on their way to the occipital lobe and are collectively known as Meyer's loop

Question 35

Damage to the inferior optic radiations will produce what visual field deficit/pattern?

Answer 35

Superior quadrantopic field (Pie in the Sky pattern)

Question 36

Fibers from the superior optic radiations will loop into __________ lobe on their way to __________ and are collectively known as ______________.

Answer 36

Parietal lobe on their way to the occipital lobe and are collectively known as Baums' Loop

Question 37

Damage to the superior optic radiations will produce what visual field deficit?

Answer 37

Inferior quadrantopic field (Pie on the Floor pattern)

Question 38

The primary visual cortex is also known as _______ and ______________.

Answer 38

V1 and Brodmann area 17

Question 39

The primary visual cortex is located predominantly on the medial surface of the _________________.

Answer 39

Occipital lobe

Question 40

Calcarine fissure divides the visual cortex into an _________ and ______________ gyrus.

Answer 40

Upper (cuneus gyrus) and lower (lingual gyrus)

Question 41

The striate cortex is involved in ____________ vision.

Answer 41

Binocular

Question 42

Where do the superior optic radiations terminate in the striate cortex?

Answer 42

Superior to the calcarine fissure (cuneus gyrus)

Question 43

Where do the Inferior optic radiations terminate in the striate cortex?

Answer 43

Below the calcarine fissure (lingual gyrus)

Question 44

Damage to the superior optic radiations causes ____________________.

Answer 44

Contralateral lower quadrantanopia

Question 45

Damage to the inferior optic radiations causes _____________________.

Answer 45

Contralateral upper quadrantanopia

Question 46

The visual cortex must send visual information to which higher visual association areas?

Answer 46

Area 18 (parastriate cortex) and area 19 (peristriate cortex)

Question 47

Visual association areas in one hemisphere are interconnected to the same areas in the contralateral hemisphere via ______________.

Answer 47

Inter-hemispheric commisural pathway in the posterior corpus callosum

Question 48

Visual information is ultimately analyzed in the dominant __________ lobe.

Answer 48

Parietal

Question 49

Most often times, Lesions of the left angular gyrus of the parietal lobe will result in _______________.

Answer 49

Faulty integration of visual information despite intact primary visual pathways

Question 50

The Oculomotor nucleus will give rise to lower motor neurons supplying _____________.

Answer 50

EOMs (specifically Levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, inferior oblique)

Question 51

Edinger-Westphal nucleus gives rise to preganglionic parasympathetic neurons to supply the ___________ and ____________.

Answer 51

Sphincter pupillae and ciliary muscles

Question 52

Trochlear nucleus gives rise to lower motor neurons supplying the ____________.

Answer 52

Superior Oblique muscle

Question 53

Abducent nucleus gives rise to lower motor neurons supplying the __________.

Answer 53

Lateral rectus muscle

Question 54

Accommodative pathway: Area 19 (visual association cortex) receives visual feedback from area ____________.

Answer 54

17 (primary visual cortex)

Question 55

Describe the accommodative pathway?

Answer 55

1. Area 19 (Visual Association Cortex) receives feedback from Area 17 (Primary Visual Cortex) 2. Association detects blur & projects to PTN 3. Pretectal projects bilaterally to EW 4. Preganglionic fibers travel on CN3 & synapse in ciliary ganglion 5. Postganglionic fibers go to sphincter muscle to constrict pupil & to ciliary muscle to thicken the lens 6. CN3 carries out convergence of the eyes via MR

Question 56

Accommodative triad

Answer 56

Accommodation, constriction, convergence

Question 57

Pupillary Light Reflex Pathway

Answer 57

1. Optic tract fibers directly project to pretectal nucleus 2. Pretectal nucleus projects to EW nucleus bilaterally 3. Preganglionic fibers from EW nucleus synapse in the ciliary ganglion 4. Postganglionic fibers project to sphincter pupillae muscle to constrict the pupil

Question 58

Consensual reflex of the pupil

Answer 58

Stimulation of one eye causes reflex in both eyes

Question 59

Pupillary Dilation Pathway

Answer 59

Posterior hypothalamus projects to cells in the intermediolateral cell column of the spinal cord at the upper thoracic levels C8-T2 ## Footnote Preganglionic fibers synapse onto Postganglionic neurons in the superior cervical ganglion ## Footnote Postganglionic fibers from the internal carotid nerve plexus and follow the internal carotid artery and its branches ## Footnote Postganglionic fibers supply dilator pupillae muscles via the long ciliary nerve

Question 60

A lesion of the superior optic radiations in the right parietal lobe will result in what visual field defect?

Answer 60

Left inferior quadrantanopia

Question 61

A right inferior quadrantanopia suggests a lesion where in the visual pathway?

Answer 61

Superior optic radiation (Baum's loop) in the left parietal lobe