CN I, II, II, IV and VI Flashcards
1
Q
olfaction
A
detects volatile chemicals that are drawn into nasal cavity
2
Q
humans can detect___ different odors
A
10,000
3
Q
olfaction is made up of
A
olfactory bulb, tract, and epithelium
4
Q
olfaction orientation
A
bilateral
5
Q
olfactory epithelium contains how may receptor cells
A
3 million
6
Q
olfactory epithelium contains sensory endings from
A
CN V
7
Q
the olfactory receptor is what kind of neuron
A
small bipolar
8
Q
at the dendrite ends of olfactory vesicleare
A
cilia spree over the surface in allure of mucus
9
Q
mucus in the olfactory receptor is secreted by
A
bowman gland
10
Q
lifespan of chemosensitive cilia in olfactory receptor
A
1-2 months then the are replaced
11
Q
axons from olfactory receptors are among the ____ and ____
A
thinnest and slowest
12
Q
olfactory fila
A
collection of axon bundles (20) in the olfactory receptors
13
Q
where do the olfactory fila pass through
A
the cribriform plate of the ethmoid bone
14
Q
olfactory fila make up which CN
A
CN 1
15
Q
where are the 2nd order neurons in olfactory
A
olfactory bulb
16
Q
the olfactory bulb and tract develops as an outgrowth of the
A
telencephalon
17
Q
orientation of the olfactory tract
A
ipsilateral
18
Q
the olfactory tract has no relay in ___ and goes straight to the ____
A
thalamus, cortex
19
Q
types of cells that make up the olfactory bulb
A
mitral and tufted cells
20
Q
cranial nerve one is a ___ order neuron
A
1st order
21
Q
each type of olfacor receptor sends an axon to
A
one glomerulus of a mitral cell
22
Q
special sense are ____ neurons
A
bipolar
23
Q
olfactory tract
A
when axons of mitral cells come together
24
Q
what regulates sensitivity of olfaction bulb
A
collateral to anterior olfactory nucleus. affects sensitive of smells
25
olfactory fibers project to both ____
both bulbs
26
olfactory fibers cross the midline in the
ANTERIOR COMMISSURE in the brain in order to talk to other side of brain
27
what stria is rudimentary in humans
intermediate olfactory stria
28
three different strai
lateral (primary) olfactory stria, intermediate, medial (secondary)
29
location of lateral olfactory strai
cortex over uncus
30
medial olfactory stria location and function.
subcallosal region. emotional response to smell
31
the lateral olfactory stria projects to the
pyriform area
32
olfactory information orientation
ipsilateral (except the ones in the anterior white commissure)
33
olfactory information is sent to what 5 areas of the brain
hypothalamus, hippocampus (integrated memory), orbital cortex, amygdala, thalamus (goes back around to the dorsal medial nucleusthalamus)
34
what kind of sense is olfactory
special sensory afferent
35
cns origin or termiatio of the olfactory bulb
lateral geniculate nucleus, superior colliculus, hypothalamus
36
peripheral origin of the olfactory epithelium
retinal ganglion cells
37
zonules
attaches ciliary muscle to lens
38
fovea
area of highest acquit in the eye
39
focus of the eye requires
refraction light
40
what accounts for third of the sys refractive power
lens
| for near/far objects
41
most refraction is in the _____ of the corneal surface
air-water interface
42
iris
affects brightness and quality of image focused one etina
43
what are the 2 smooth muscles in the iris that control the size of the pupil
pupillary sphincter and the pupillary dilator
44
which is strong there pupillary sphincter or dilator
sphincter
45
smaller pupil =
improved ocular performance
46
the first layer of photoreceptor synapses on what kind of cells
bipolar and horizontal
47
after the first photoreceptor synapse where do the bipolar and horizontal cells go
bipolar cells: project 2nd synapses
| horizontal cells: spread laterally and interconnect receptors, bipolar cells and other horizontal cells
48
what kind of cells can bipolar cells in retina terminate on
ganglion cells or amacrine cells
49
amacrine cells
interconnect bipolar cells, ganglion ells, and other amacrine cells
50
bipolar, gangion and amacrine fibers collect to for the
optic nerve
51
photoreceptor cells are
highly specialized with different structural regions
52
outer segments of photoreceptor cells contain
visual pigment protein
1. Rods: Rhodopsin; low acquit and monochromatic
2. cones: cone pigments; high acuity color vision, need lots light
53
inner segments of photoreceptor cells
contain mitochondria to synthesize pigment
54
where are photons absorbed
photoreceptor cells
55
the ganglion cells on the surface of the retina have...
axons in optic nerve which travel to the optic chasm (partial decussation)
56
once axons in the optic nerve enter the tract they travel to the
1. lateral geniculate nucleus ;thalamic relay for vision
| 2. or superior colliculus and hypothalamus
57
if visual fields are intact you know
lower half to the brain is intact
58
optic nerves in the nasal region of the retina
gross over in the optic chasm and go to the opposite side
59
the lateral geniculate nucleus (LGN) is __ layered
6 layered, precept retinotopic arrangement
60
each layer of the lateral geniculate gets input from
one eye
1. contralateral eye 1,4,6
2. ipsilateral eye 2, 3, 5
61
paravocellular layers (LGN)
color and form (3-6)
62
magnocellular layers (LGN)
movement and contrast (1-2)
63
in LGN projects the fibers representing the inferior visual fields are
most superior in the radiations and vice versa
64
optic tract fibers that bypass the LGN go to the
superior colliculus and pretectal area (junction of midbrain and diencephalon)
65
what affects the circadian rhythm (sleep schedule)
hypothalamus and suprachiasmatic nucleus
66
fibers from he temporal half of the retina enter
ipsilateral optic tract
67
each optic tract "sees"
the contralateral visual field
68
depth perception needs
to examine comparable areas for both retinas, accomplished by chiasm
69
hemianopia
loss of half a visual field
70
quadrantanopia
loss of one quarter of a visual vield
71
homonymous
similar visual field loss in each eye
72
heteronymous
two eyes have non-overlapping visual fields
73
damage anterior to the optic chasm only affects the
ipsilateral eye
74
damage to the chasm causes
heteronymous deficits
75
damage to the optic tracts causes
homonymous deficits
76
what are the occulomotor muscles
superior oblique, superior rectus, medial rectus, lateral rectus, interior rectus, inferior oblique
77
superior rectus m. function
elevation of eye
78
inferior rectus m. function
depression of eye
79
medial rectus m function.
adduction of eye
80
inferior oblique m. function
external rotation of eye. up and in
81
superior oblique m. function
internal rotation of eye. down and out
82
lateral rectus m. function
abduction of eye
83
abducent nerve (CVI) controls which muslce
lateral rectus
84
the oculomotor nerve (CN II) controls which m
inferior oblique, superior rectus, medial rectus
85
the trochlear nerve (CN IV) control which m
superior oblique
86
parasympathetics of cranial nerve 3 reside in
the edinger westphal nucleus
87
describe the parasympathetic input to the eye
starts in midbrain. goes to dinger westpha nucleus which sends projections to ciliary ganglion. cell bodies synapse on ciliary ganglion to dilate pupil. pupillary constrictor muscles decrease pupil diameter
88
constriction of pupils in response to light involves ___ sets of neurons
4
89
afferent limb: retinal ganglion cells to
pretectal nuclei
90
each pretectal nucleus is linked to both ____ via the ____
Edinger-westphal nucleus via the posterior commissure
91
pre ganglions parasym. fibers in CN II synapse
in ciliary ganglion
92
postganglionic parasymp. fibers in short ciliary nerves
enter the iris to supply sphincter constrictor of pupillae
93
the preganglionic sympathetic fibers emerge in the _____ and ascend the _____ to ___
thoracic ventral nerve root and ascend sympathetic chain to superior cervical ganglion
94
the postganglionic sympathetic fibers run along the ______
external and internal carotid arteries and their branches
95
cavernous sinus
where sympathetic postganglionic optic fibers leave the internal carotid and join V1
96
why is the lens flat at resr
tension exerted by suspensory ligament
97
to view objects close up the ciliary muscle ___- and the lens suspensory ligaments____ and the lens ____
contracts; relax, bulges (thickens)
98
when the sphincter papillae contract it
decreases light coming through lens periphery
99
convergence is due to
increased tone in the medial rectus muscle; cross eyed
100
result of injury to CNIII
eye is "down and out"; the eye on the same she (ipsilater) to lesion with deviate laterally because the medial rectus is weak and th lateral rectus will be unopposed;
patient can't move eye medially
101
diplopia
double vision; can result from injury in cranial nerve III.
102
droopy eyelid is an injury to
CN III
103
mydriasis
pupil on affected side is dilated (result of injury to CN III) because pupillaryr dilator is unopposed because sphincter and ciliary are dysfunctional
104
pupil doesn't contract in reposes to light is an injury in
CN III
105
what axon type is Edinger westphal nucleus
General visceral efferent
106
course of the trochlear nerve (CN IV)
axons leave nucleus and course dorsally, decussate,and exit brainstem on dorsal surface
107
CN IV lesion
head tilts away from lesion and eye points up (contralateral side for head tilt)
108
CN VI
abducens nerve
109
abducens nerve innervate the
ipsilateral lateral rectus (abduct)
110
where is the abducens (CN VI) located
floor of 4th ventricle (caudal pons)
111
where is the CN VI nucleus located
facial colliculus
112
injury to CN VI (abducens)
medial strabismus (affect eye deviated medially). ipsilateral eye with not abduc past mid position and contralateral eye will not adduct past mid position
113
why does the course of the abducens nerve(CNVI) make it susceptible to increased intracranial pressure
its long intracranial course
114
Medial longitudinial fasiculus
allow coronation of head and eye movement
115
which CN motor nuclei ascend in the MLF
III, IV, VI
116
Medial longitudinal fasiculus injury
eye on same side of lesion won't move past mid position during horiztonal gaze; but cn VI nuclei are still intact so lateral movement is still intact
117
scanning
eyes move from one visual target to another in high-speedmovement saccades; gaze centers founding reticular formation
118
tracking
smooth pursuit eyes follow area of interest across visual field
119
compensation
are held on object of interest during head movement (vestibuloocular reflex)
