Anatomy 9a CN1-6 Flashcards

1
Q

If olfaction a mechanical or chemical receptor?

A

Chemical

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2
Q

T/F Olfactory receptor cells are neurons in the nasal cavity

A

True

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3
Q

What bone is the roof of the nasal cavity?

A

Ethmoid Bone

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4
Q

Which hair system IS neurons:
Olfactory
Cochlea
Vestibular

A

Olfactory

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5
Q

Describe the olfactory sensory/receptor cells (hair cells) found in the sensory organ olfactory epithelium
(What type of neuron)

A

Bipolar neurons with cilia (olfactory hairs) on end of dendrite

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6
Q

What are the supporting cells found in the olfactory epithelium?

A

Mucous membrane lining of nasal cavity that function to support, nourish, insulate, and detoxify olfactory receptor cells (neuroglia)

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7
Q

What are the basal stem cells found in the olfactory epithelium?

A

Neurons continually undergoing replication to replace olfactory receptor cells which have a life span of 1 month

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8
Q

What are the olfactory glands found in the olfactory epithelium?

A

Provide mucous to cover surface of olfactory epithelium to dissolve odor molecules so they can interact with receptor cells

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9
Q

T/F: Odor molecules must be dissolved before they can interact with olfactory sensory/receptor cell receptors

A

True

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10
Q

What is adaption in regard to olfactory apparatus?

A

Process by which we decrease our sensitivity to continuous exposure to a particular odor (50% adaptation in first second of exposure)

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11
Q

Describe the olfactory pathways starting with an odor ending at olfactory bulb

A

Odor (molecule in air) -> molecule dissolves in mucous of nasal surface -> molecules binds to combination of olfactory receptors protein (ligand binding) -> Chemical gated channels open (Ca/Cl) -> Depolarize due to graded potential on dendrite/soma in olfactory epithelium (CN 1 not considered ganglia) -> AP down axon CN 1 -> CN 1 goes through cribriform plate to olfactory bulb

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12
Q

T/F: Olfactory bulb is layered for processing signals and is NOT topographically representative of olfactory epithelium for discriminating signals

A

F:

IS topographically representative of olfactory epithelium for discriminating signals

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13
Q

T/F: Olfactory bulb does not always send signals

A

False: Olfactory bulb is always sending signals and a new signal changes the pattern of signaling

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14
Q

Olfactory tract carries new pattern of signals from olfactory bulb to:

A
  1. Ipsi and contralateral limbic structures (amygdale, entorhinal cortex, hippocampus, prefrontal cortex, Insula (reflex to odor)
  2. Temporal? either directly or via thalamus for odor discrimination
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15
Q

What are the 5 accessory structures of the eye?

A
Eye lid
Eye brow
eye lashes
muscles
lacrimal apparatus
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16
Q

Eye lid:
Function:
What muscles close lid and what CN?
What is the inner lining of eye lid?

A
  • Function - protect eye
  • Orbicularis occuli orbital and palpebral close eye (CN 7)
  • Palpebral conjunctiva is the inner lining of eye lid (continuous with sclera)
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17
Q

What is the lacrimal apparatus?

Describe pathway

A
  • Lacrimal glands produce lacrimal fluid (tears) which is released (CN 7)
  • Secrete fluid superior/lateral -> flows diagonally to inferior/medial lacrimal canals-> empty into nasal cavity
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18
Q

What are the extrinsic eye muscles? (6)

A

Superior/inferior rectus
lateral/medial rectus
superior/inferior oblique

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19
Q

What is the sclera of the eye?
Continuous with what?
Avascular/vascular?

A
  • Continuous with the cornea

- Forms an AVASCULAR dense “white” CT covering the eye

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20
Q

The sclera of the eye for an attachment between eye and what 3 structurs?

A
  1. Palpebral conjunctiva of eye lid to close off eye socket
  2. Dural sheath (epineurium) of CN 2
  3. Tendons of extraoccular muscles
    - > Effectively hold eye in place
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21
Q

What is the cornea?

Avascular/vascular?

A

AVASCULAR area covers anterior surface of eye ball

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22
Q

The vascular middle layer of the eye is called what?

A

Uveal tract

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23
Q

What is the choroid of the eye?

A

Middle layer

Contains blood vessels

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24
Q

What is the ciliary body of eye?

A

Anterior modification of choroid

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25
Q

What is the ciliary processes of ciliary body?
What does it produce?
What does it attach to?

A
  • Form circular ridge
  • Contains capillaries
  • Produce aqueous humor
  • Attach to suspensory ligaments which connect to lens
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26
Q

Ciliary muscle:
What is it?
What CN innervation?

A
  • Circular smooth muscle at base of ciliary process that changes shape of lens by pulling suspensory ligaments (visual accommodation for near/far vision)
  • CN3 parasympathetic innervation
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27
Q

Describe what happens when ciliary muscle contracts?

Increase/decrease CN stimulation?

A

Decrease tension of lense -> convex surface (opening decreases) -> near vision
-Increase CN 3 stimulation

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28
Q

Describe what happens when ciliary muscle relaxes?

Increase/decrease CN stimulation?

A

Increase tension of lense -> flat surface (opening increases) -> far vision
-Decrease CN 3 stimulation

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29
Q

What is the iris?

A
  • Area of eye color

- Smooth muscle fibers that change size of opening (pupil) through which light enters eye ball

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30
Q

The circular muscle of the iris does what?

Innervated by?

A
  • Constricts pupil

- Parasympathetic CN 3

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31
Q

The radial muscle of the iris does what?

Innervated by?

A
  • Dilate the pupil

- Sympathetic (carotid plexus/sup cervical plexus)

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32
Q

What is the retina?

A
  • Inner layer

- Contains neuron sensor receptor cells and is beginning of visual pathway

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33
Q

What is the pigment epithelium of retina?

Neural/non-neural epithelial cells?

A
  • Outer layer of retina next to choroid

- Composed of non-neural pigmented epithelial cells

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34
Q

What is the photoreceptor layer of retina?
Rods-
Cones-

A

-Neurons contain sensor receptor processes with photo-pigment
Rods - dim light vision produces gray images (100 million/retina)
Cones - bright light vision produces color images (5 million/retina)

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35
Q

What is the outer nuclear layer of retina?

A

Soma of rods and cones

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36
Q

The outer synaptic layer of retina is also called?

A

outer plexiform layer

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37
Q

What is the inner nuclear layer of retina?

A

Bipolar layer for initial image processing

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38
Q

What is the ganglion cell layer of retina?

A
  • Bodies of ganglia cells (multipolar ganglia cells NOT pseudounipolar)
  • Axons of ganglia cells form optic nerve fibers (inner most layer of the retina next to vitrous body)
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39
Q

Which way does light travel?
Inner optic nerve cell layer -> outer pigment epithelium/photoreceptor layer
or vice versa?

A

Inner optic nerve cell layer -> outer pigment epithelium/photoreceptor layer

40
Q

Which way do nerve impulses travel?
Inner optic nerve cell layer -> outer pigment epithelium/photoreceptor layer
or vice versa?

A

Outer pigment epithelium/photoreceptor layer -> Inner optic nerve cell layer

41
Q

What is the optic disk of the retina?

T/F: Optic disk contains sensory receptor cells

A

-Blind spot
-Site where optic nerve (CN 2) enters and blood vessels (opthalmic A/V) enter/exit the eye ball
FALSE: Contains no sensory receptor cells (rods/cones)

42
Q

What is the macula lutea of the retina?

Contains rods or cones?

A

Visual axis = focal point

-Contains central fovea which is an area of only cones and serves as the area fo highest visual resolution

43
Q

What is the ora serrata of the retina?

A

Anterior margin of the neural (photoreceptor) retina

44
Q

Lens:
Connected by what to what?
Functions?

A
  • Connected by suspensory ligaments to ciliary process/muscles
  • Functions to bend light to focus image on retina
  • more curved = near, contraction of ciliary
  • Less curved = far, relaxation of ciliary
45
Q

What is the vitreous body (humor)?

A
  • Located between lens and retina

- Contains phagocytes that remove floating debris

46
Q

What is the anterior cavity of the eye?
What does it contain?
How is the liquid drained?

A

Between the cornea and the lens

  • Contains aqueous humor which is filtered blood plasma secreted by the ciliary body and drained by the canal of Schlemn into the venous system in the anterior chamber
  • Nourishes lens and cornea
47
Q

Refraction:
How are images changed when it gets to retina?
What love corrects images?

A

Cornea and lens bend light rays to focus them on the retina

  • Images are inverted upside down and reversed right to left
  • Brain occipital lobe corrects retinal images to give them proper orientation
48
Q

Accomodation:
What is it?
Describe change for near objects:
Describe change for far objects:

A

-Process by which curvature of lens is changed to focus light rays on retina
Near objects: curvature becomes greater (ciliary muscles contract and decreases tension on suspensory ligaments)
Far objects: Curvature flattened (CN3 parasympathetic inhibition - ciliary muscles relax and increase tension of suspensory ligaments)

49
Q

Myopia (nearsightedness):

A

Distant objects can’t be seen clearly because the image is focused in front of retina
(can only see near objects, use concave lens to fix)

50
Q

Hypermetropia (farsightedness):

A

near objects can’t be seen clearly because image is focused behind retina
(can only see far objects, use convex lens to fix)

51
Q

Presbyopia

A

Lens becomes less elastic with age and therefore less convex moving the focal point for near vision further away from eyes

52
Q

Convergence:

Necessary for what type of vision

A
  • Process of moving the eyes medially for near vision so that image of objects hit the equivalent spot in both retinas
  • Maintain overlap of visual fields of both eyes for BINOCULAR VISION which allows depth perception and 3 dimensional perception
53
Q

Light pathway starting with light ending at retina

A

Light -> object -> reflected light -> cornear -> aqueous humor -> lens -> vitrous body -> retina

54
Q

Pigment cells

A

absorb light = quench

55
Q

photoreceptor cell

A

transduce light to nerve impulse

56
Q

Describe nerve signal within retina:

A

Change pattern of depolarization/hyperpolarization = excitation/inhibition neuron layers within the retina to change pattern of signals on ganglion cell axons/CN2

57
Q

Where are AP generated in visual pathway?

A

In ganglion cells

58
Q

APs exit the eye by?

A

optic nerve (CN 2)

59
Q

Where do the two optic nerves meet?

A

Optic chiasm

60
Q

Impulses from nasal half of retina go where?

A

Cross over to opposite side of the brain

61
Q

Impulses from temporal half of retina go where?

A

Stay on same side of brain

62
Q

Where are optic tracts formed?

A

After the optic chiasm

63
Q

What does the left optic tract contain?

A

Left temporal and right nasal retina go to left brain

= right visual field

64
Q

What does the right optic tract contain?

A

right temporal and left nasal retina go to the right brain

= left visual field

65
Q

The optic tracts will send signals to what 3 areas?

A
  1. Pretectal area -> pupillary reflex
  2. Superior colliculus -> horizontal tracing eye movements and head turning
  3. Lateral geniculate nucleus of thalamus
66
Q

Spacial relationships of visual/retinal fields are maintained where?

A

Lateral geniculate nucleus

67
Q

Where are images processes to be in proper perspective?

A

Visual cortex

68
Q

External Eye muscles:
Originate where?
Insert where?

A

Originate on orbital bone

insert on sclera

69
Q

Levator Palpebrae superioris
Innervation -
Action -

A

Innervation - CN 3

Action - elevate eye lid (open)

70
Q

Orbicularis occuli
Innervation -
Action -

A

Innervation - CN 7

Action - depress eye lid (close)

71
Q

Superior oblique
Innervation -
Action -

A

Innervation - CN 4 trochlear
Action -
1. From near focus (eyes adducted) will further adduct
2. From far focus (eyes abducted) will further abduct
3. Will also depress and medially rotate

72
Q

Inferior oblique
Innervation -
Action -

A

Innervation - CN 3
Action -
1. From near focus (eyes adducted) will further adduct
2. From far focus (eyes abducted) will further abduct
3. Will elevate and laterally rotate

73
Q

Superior rectus
Innervation -
Action -

A

Innervation - Cn 3

Action - elevate (slight add and medial rotate)

74
Q

Inferior rectus
Innervation -
Action -

A

Innervation - CN 3

Action - depress (slight add and lateral rotate)

75
Q

Medial rectus
Innervation -
Action -

A

Innervation - CN 3

Action - adduct

76
Q

Lateral rectus
Innervation -
Action -

A

Innervation - Cn 6

Action - abduct

77
Q

Cn3 neuron types: (2)

A
  1. Somatomotor to skeletal muscles

2. Visceromotor (parasympathetic) to smooth muscles and glands

78
Q

The nuclei of CN 3 occulomotor found where in brain stem?

  1. Somatomotor nuclei
  2. Visceromotor (parasympathetic) nuclei
A
  • Found at level of midbrain1.
    1. Somatomotor nuclei - occulomotor nucleus
    2. Visceromotor nuclei - edinger-westphal nucleus
79
Q

How does CN 3 enter orbital cavity?

A

Through superior orbital fissure

80
Q

What muscles does the superior division of CN 3 innervate? (2)
Ipsilateral/Contralateral?

A

Superior division - ipsilateral

  1. Superior rectus
  2. Levator palpebrae
81
Q

What does the inferior division of CN 3 innervate?

Ipsilateral/Contralateral?

A

Inferior division - ipsilateral

  1. Inferior rectus
  2. medial rectus
  3. inferior oblique
  4. Ciliary ganglion (parasympathetic)
82
Q

How does inferior division of CN 3 affect the

  1. Ciliary body/ciliary muscles? (describe stimulation/no stimulation)
  2. Circular muscles of iris?
A
  1. Ciliary body/ciliary muscles? accommodation
    Stimulation - relax suspensory lig -> increase curvature of lens (near vision)
    No stimulation - pull suspensory lig -> decrease curvature of lens (far vision)
  2. Circular muscles of iris? pupil constriction
83
Q

CN 4 Neuron types: (2)

A
  1. Somatomotor to eye muscle

2. Somatosensory proprioception

84
Q
Pathways of CN4 (trochlear n) start with nucleus
Where nucleus located?
Where does it cross?
How does it enter the orbital cavity?
What muscles does it innervate?
A
  1. Nucleus = brain stem at level of midbrain
  2. Cross pretectum
  3. Cranial foramen = superior orbital fissure
  4. Contralateral superior oblique (somatomotor and sensory)
85
Q

CN 6 neuron type (1):

A
  1. Somatomotor to lateral rectus m
86
Q

Describe pathway of CN 6 from brain stem
Where nucleus located in brain stem?
How does it enter the orbital cavity?
What muscle does it innervate?

A
  1. Brain stem nuclei at level of open medulla
  2. Through the superior orbital fissure
  3. Ipsilateral Lateral rectus m to abduct eye
87
Q

Describe pathway of sympathetics
Start with preganglionic neuron lateral horn T1 ->
What head structures?

A
  1. preganglionic neuron lateral horn T1 ->
  2. postganglionic neuron in Superior cervical ganglia of paravertebral chain ganglia ->
  3. Carotid/sympathetic plexus of nerves ->
  4. Head structures: iris, glands
88
Q

What is the pupillary light reflex?

A

Shine light in one eye, both should constrict

89
Q

Describe 1st part of pathway of pupillary reflex
Start: Light
End: pre-rectal area

A
  1. Light
  2. Ganglion cells
  3. optic n/optic tract
  4. pre-tectal area (rostral of superior colliculus
90
Q

Describe 2nd part of pathway of pupillary reflex
Start: pre-rectal area
End: Pupil constricts

A
  1. Pre-tectal area
  2. Edinger-Westphal nucleus on both sides (bilateral projection via posterior commissure)
  3. Parasympathetic preganglionic
  4. Ciliary ganglia
  5. Parasymp postganglionic
  6. contract circular m or iris
  7. pupil constricts
91
Q

Direct pupillary light reflex

A

Eye shined light into constricts it’s pupil

92
Q

Concensual pupillary light reflex

A

Eye did not shine light into also constricts its pupil

93
Q

Accommodation reflex -

A

Accommodation - change focus from far to near object

94
Q

Accommodation reflex: Describe 1st part of pathway
Start: Motor cortex
end: Activate edinger-westphal

A
  1. Motor cortex
  2. CN 3
  3. Medial rectus muscles on both sides
  4. Adduct to facilitate convergence of visual field
  5. Papillary constriction reflex (pupillary constriction)
  6. Activate edinger-westphal
95
Q

Accommodation reflex: Describe pathway
Start: Activate edinger-westphal
end: Near vision

A
  1. Activate edinger-westphal
  2. Ciliary ganglia
  3. Ciliary muscles contract
  4. increase curvature lens
  5. Near vision