Neuro Exam 2 Lecture 4

Front 1

What are the special senses?

Back 1

-Visual
-auditory
-vestibular
-olfaction
-taste

Front 2

____________ and ___________ are chemo senses

Back 2

taste and smell (olfaction)

Front 3

Of the special senses, which are somatic afferent and which are visceral afferent?

Back 3

Somatic afferent: visual, auditory, vestibular

Visceral afferent: olfaction, taste

Front 4

What are the cranial nerves conveying special senses?

Back 4

CN I, CN II, CNVII, CN VIII, CN IX, CN X

Front 5

which cranial nerves are associated with taste?

Back 5

CN VII, IX, and X

Front 6

What are the specialized receptors associated with taste?

Back 6

taste buds

Front 7

In reference to taste, the first order pseudounipolar neurons have cell bodies located where?

Back 7

In the cranial nerve ganglia of CN VII, CN IX, and CN X (functionally equivalent to the posterior root ganglion)

Front 8

Where do the first order taste neurons synapse?

Back 8

In the solitary nucleus

Front 9

Where is the solitary nucleus located?

Back 9

In the rostral medulla

Front 10

What is the primary viscerosensory nucleus of the brainstem?

Back 10

the solitary nucleus

Front 11

Is there crossing in the taste pathway?

Back 11

No, it is an ipsilateral pathway

Front 12

From the solitary nucleus in the rostral medulla, the second order taste neuron ascends on the _____________ side to synapse where?

Back 12

ipsilateral side

Axons project to synapse in VPM in the thalamus

Front 13

Where are the second order taste neuronal cell bodies?

Back 13

in the solitary nucleus of the rostral medulla

Front 14

Where are the third order neuronal cell bodies in the taste pathway?

Back 14

in the VPM

Front 15

Where do the third order neurons synapse in the taste pathway?

Back 15

In the gustatory cortex

Front 16

What is the gustatory cortex?

Back 16

the taste cortex on that postcentral gyrus (taste pathway)

Front 17

When people refer colloquially to a loss of taste, what they are really referring to is a loss of _______, which is actually more closely associated with your sense of _________

Back 17

flavor

smell

Front 18

What type of neurons are first order neurons in the olfaction pathway?

Back 18

bipolar neurons

Front 19

Where are the cell bodies of the olfactory neuronal cell bodies found?

Back 19

In the olfactory epithelium

Front 20

How do the olfactory nerves enter the skull?

Back 20

Through the cribriform plate of the ethmoid bone

Front 21

Where do the first order bipolar olfactory neurons synapse?

Back 21

in the olfactory bulb

Front 22

Why is there such a strong connection between smells and memories?

Back 22

Because from the olfactory cortex, there is a strong projection to the limbic system

Front 23

Where are the cell bodies of the olfactory second order neurons located?

Back 23

in the olfactory bulb

Front 24

Where do the olfactory second order neurons synapse after they form the olfactory tract?

Back 24

In the olfactory cortex

Front 25

Does olfaction have a third order neuron?

Back 25

There are, except for the story gets so complicated, at that point, that for us, it isn't worth talking about (but they would be in the olfactory cortex)

Front 26

In the eye, what does the iris do?

Back 26

It controls the pupillary aperture diameter in response to varying light levels (controls aperture to let light in)
(pupillary dilator muscle and a pupillary constrictor muscle)

Front 27

What muscle controls the shape of the lens for accommodation, or focusing the image?

Back 27

The ciliary body

Front 28

which part of the eye contains light-sensitive photoreceptors and associated neurons for initial visual processing?

Back 28

The neural Retina

Front 29

What prevents scattering of stray light?

Back 29

Retinal pigment Epithelium

Front 30

What are the two parts of the retina?

Back 30

-neural retina
-retinal pigment epithelium

Front 31

What becomes separated from the retina when you have a retinal detachment?

Back 31

The neural retina tears away from the pigment epithelium layer

Front 32

in the Retina, light travels from ____________ to ____________

Back 32

anterior to posterior

Front 33

In the retina, _____________ travels from posterior to anterior to exit via the optic nerve

Back 33

information processing

Front 34

What are the layers of the retina? (from posterior to anterior)

Back 34

-Retinal pigment epithelium
-photoreceptors
-first order bipolar neurons
-second order neurons (retinal ganglion cells)
-optic nerve (the axons of retinal ganglion cells

Front 35

________________ are not true neurons. They are modified epithelial cells that can act like neurons, but are not true neurons

Back 35

Photoreceptors (rods and cones)

Front 36

In the retina, the bipolar first order neurons will then synapse on second order neurons, or _______ __________ ________

Back 36

retinal ganglion cells

Front 37

The axons of the retinal ganglion cells, or the second order neurons, form the ______ ________ with their axons

Back 37

optic nerve

Front 38

What is a fovea?

Back 38

Fovea means pit, so the fovea is a depression in a specific location in the back of the eye

Front 39

What is the area or region with highest visual acuity?

Back 39

the fovea centralis

(other retinal layers are pushed aside so that more light reaches photo receptors, and it has the highest concentration of cone photoreceptors which have better spatial resolution)

Front 40

What is the blind spot in your eye?

Back 40

It is the optic disc; the point where the axons of the optic nerve exit the eye (the axons of the retinal ganglion cells).

Front 41

Are there any photoreceptors, bipolar neurons, or retinal ganglion cells present at the optic disc?

Back 41

no. Therefore, there is no vision right here. - blind spot

Front 42

Photoreceptors consists of ____1_____ and ____2____, and are responsible for _______3_______

Back 42

1. rods
2. cones
3. phototransduction

Front 43

What is phototransduction?

Back 43

It is conversion of light energy (photons) to electrochemical signals

Front 44

In Rods and cones, ___1___ have chromatic (color) vision and three types of photopigments, while the other, ____2_____, have ____3___ type(s) of photopigment

Back 44

1. Cones

2. Rods

3. one

Front 45

Are there more rods or cones in the retina?

Back 45

There are more rods- ~ 20 times more rods than cones

Front 46

____1_____ are not present in the central fovea, while ____2_____ are concentrated in the central fovia

Back 46

1. rods not present

2. cones concentrated

Front 47

Rods are concentrated where?

Back 47

in the periphery

Front 48

___1_____ have high visual acuity and better spatial resolution, while ______2_____ have low visual acuity, so worse spatial resolution

Back 48

1. Cones- high and better

2. Rods- low and worse

Front 49

Rods have ____1____ sensitivity to light, and are specialized for _____2____ vision, while cones have ____3_____ sensitivity to light, and a specialized for _____4____ vision.

Back 49

Rods- high sensitivity- night vision

Cones- low sensitivity- day vision

Front 50

What is one of the names of the visual pathway?

Back 50

The retino-geniculo-striate pathway

Front 51

Striate cortex is another name for _____________

Back 51

visual cortex

Front 52

Where are the neuronal cell bodies of the visual pathway located? (hence the name of the visual pathway)

Back 52

-Retina (retinal ganglion cells)
-Lateral geniculate nucleus
-those cell bodies then project to the visual cortex (has an interesting looked to it- striped=striate cortex)

Front 53

Where is the lateral geniculate nucleus located?

Back 53

In the thalamus

Front 54

The thalamus is the relay to the _______

Back 54

cortex. Remember you have the VPL, VPN, and now the LGN here (lateral geniculate nucleus)

Front 55

The sensory receptors are the first step in the visual pathway. What are these?

Back 55

Photoreceptors- rods and cones

Front 56

The first order neurons in the visual pathway are the ______1_____ neurons, and then you have the second order neurons which are the ____2___ ______ ________, whose axons form the__3_____ _______

Back 56

1. bipolar

2. retinal ganglion cells

3. optic nerve (CN II)

Front 57

In the visual pathway, is there a complete crossing, or decussation of the second order neurons?

Back 57

no, at the optic chiasm there is partial decussation, but there is not a complete crossing of axons, some of them stay ipsilateral

Front 58

What occurs in the visual pathway starting at the second order neurons?

Back 58

The second order neuronal retinal ganglion cell bodies are in the retina and then their axons form the optic nerve, and then there is partial decussation at the optic chiasm where the neurons will then continue to travel posteriorly via the optic tract to the LGN- where there are now third order neuronal cell bodies, which project via optic radiation to the primary visual cortex, or Brodemann's area 17

Front 59

Where are the cell bodies of the third order neurons in the visual pathway?

Back 59

In the LGN

Front 60

From the LGN, where do the third order neurons go?

Back 60

The project via optic radiation to the primary visual cortex, or Brodmann's area 17

Front 61

The _________ is a layered structure that maintains a precise retinotopic map of the visual field (a visual spatial map)

Back 61

LGN- lateral geniculate nucleus of the thalamus

Front 62

axons of the _________ _________ cells are ultimately destined to synapse on cells in the LGN

Back 62

lateral ganglion cells

Front 63

Where is the LGN located?

Back 63

Very posteriorly in the thalamus - has a very characteristic layered structure

Front 64

The primary visual cortex is sometimes called:

Back 64

V1 or Brodmann's area 17

Front 65

Where is the primary visual cortex located?

Back 65

On the occipital lobe, on either bank of the calcarine sulcus (which is on the medial aspect of the occipital lobe)

Front 66

What supplies blood to the primary visual cortex?

Back 66

The posterior cerebral artery

Front 67

The _________ ___________ is that part of the world projected onto each retina

Back 67

Visual field. Everything to your left is in your left visual field, and vise versa

Front 68

How can each visual field be divided?

Back 68

Into left and right halves (hemifields), as well as upper and lower portions, resulting in quadrants

Front 69

Each retina can be divided into a _______ half and a _________ half, as well as into superior and inferior portions

Back 69

nasal half (closest to nose)

temporal half (more lateral)

Front 70

Because of the optics of how the lens projects light onto the retina, things are:

Back 70

reversed.

Front 71

The left visual field is project onto the _________ nasal retina and the ________ temporal retina

Back 71

left nasal retinal

right temporal retina

Front 72

All fibers from the ______ half of each retina cross at the chiasm to the contralateral optic tract, while all retinal fibers from the ________ half remain ipsilateral

Back 72

Nasal half crosses

temporal half passes through chiasm without crossing and enters the ipsilateral optic tract

Front 73

because the fibers from the nasal half of each retina cross and the chiasm and the fibers from the temporal half remain ipsilateral, what does this mean?

Back 73

Each optic tract consists of fibers transmitting only the contralateral visual hemifield (any time after the optic chiasm

Front 74

What are the types of optic radiations?

Back 74

-dorsomedial fibers

-ventrolateral fibers (meyer's loop)

Front 75

The dorsomedial fibers contain information from the ____________ visual field and project to the _________ bank of the primary visual cortex

Back 75

inferior (and contralateral) visual field

Project to superior bank of primary visual cortex

look at slide 24!!!!

Front 76

The ventrolateral fibers (meyer's loop) contain information from the ____________ visual field and project to the _________ bank of the primary visual cortex

Back 76

(contralateral) superior visual field

inferior bank

Front 77

the __________________ nucleus is responsible for the circadian rhythms. What is that?

Back 77

suprachiasmatic nucleus

Circadian rhythm is your sense of day and night- the day and night cycle

Front 78

The pretectal area and Edinger-Westphal nucleus are responsible for:

Back 78

pupillary light reflex

Front 79

If there were a flash of light to the side and you reflexively turn to look, that visual reflex is mediated by what?

Back 79

The superior colliculus

Front 80

The oculomotor nerve innervates the extraocular eye muscles, but is also carrying what?

Back 80

Parasympathetic fibers for pupillary constriction

Front 81

With the pupillary light reflex, there is both an __________ and an __________ limb

Back 81

afferent and efferent

Front 82

With the afferent limb of the pupillary light reflex, where do the optic nerve fibers project?

Back 82

to the pretectal area

Front 83

With the afferent limb of the pupillary light reflex, there are bilateral projections to both _____________ nuclei.So if you shine a light in one eye, you get pupillary constriction in both eyes. This is called a:

Back 83

Edinger-Westphal nuclei

-Direct and consensual reflex

Front 84

What is a consensual reflex?

Back 84

If you shine a light in one eye, you get pupillary constriction in both eyes

Front 85

In a pupillary light reflex in the efferent limb, _______________ fibers travel via the oculomotor nerve to innervate the __________ __________ muscle

Back 85

parasympathetic (synapse in ciliary ganglion)

pupillary constrictor muscle

Front 86

If there is an infection or lesion to the optic nerve, what will occur if you shine light into the eye on the side with the lesion? why?

Back 86

Both pupils will remain dilated, because the information of this light in this retina can't get past the broken optic nerve, which means it can't reach either pretectal area, so there is neither a direct or a consensual reflex

Front 87

If there is an infection or lesion to the optic nerve, what will occur if you shine light into the eye on the side without the lesion? (the uninjured side)

Back 87

You will have a normal direct reflex and consensual reflex because that information is successfully traversing the optic chiasm and successfully arriving at the pretectal areas

Front 88

What would occur if you lesioned the optic tract?

Back 88

because light is able to cross the optic chiasm, you can successfully activate the pretactal nucleus on the opposite side, and the pretactal nucleus has bilateral projections, so you actually have a normal scenario - normal type of pupillary light reflex

Front 89

What would occur if the oculomotor nerve itself was lesioned?

Back 89

There is no way that you can activate the pupillary constrictor muscle because it is innervated by the oculomotor nerve, so no matter which side you shine light into, it is deactivated.