Flashcards in Unit II Deck (107)
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1
Cranial Nerve 0
chemoreceptors
2
Cranial Nerve I olfactory
one of oldest, by passes thalamus and goes to olfactory cortex first then thalamus
3
Where is CN 0 and CN I in the brain?
Telencephalon
4
Where is CN II in the brain?
Diencephalon
5
Where is CN III-XII except XI in the brain?
Middy
pons
medulla
rule of 4
6
Cranial nuggets (4 of them)
axons form CN nerve
all CN motor nerve=LMN
corticobular directly innervate CN V, VII, XI, XII
all CN have bilateral innervation except VII, XII
7
All cranial nerves have .. .?
2 nuclei
2 nerves
ipsilateral innervation except trochlear nerve (contralateral)
8
Nucleus of origin vs destination
cell body of fibers that make nerve
2nd order neuron for incoming sensory info
9
Brain stem lesion, ipsilateral vs contralateral
ipsilateral: cerebellar and cranial nerves
contralateral: corticospinal and dorsal column
10
Vision in general
only sensory system that provides accurate spatial info from a far
taste/touch=accurate but no distance
smell/hearing=distance but not accurate
11
Electromag spectrum
vision only encompasses small part of it
light is unidimentional, straight, and travels far=good for accurate distant sensory
12
LIght interaction with medium
refraction- light is bent and slowed
diffraction- light bounces around the object
absorption
13
Wavelength and frequency
inversely related
long wavelength, short frequency= decreased energy
short wavelength, inc frequency= increased energy
14
What determines saturation, brightness, color/hue
Wavelength= color/hue
amp= brightness
purity=saturation
15
eye anatomy
Outer: sclera/cornea
Intermediate:
ant chamber: behind cornea, front of iris/ciliary body
post chamber: behind iris/ciliary body, front of lens
inner: retina
16
Optical disk
blind spot, BV=no receptor there
17
Formation of image
flipped upside down and backward
18
Cells of retina
ganglion cell layer
bipolar layer
photoreceptor
amacrine/horizontal layer (lateral interneurons)
19
Lateral interneuron cells
inhibitory in the periphery
on ganglion cells vs off ganglion cells
20
Rods vs Cones
rods:
respond to all wavelengths of light
max sensitivity at 500nM
1 photoreceptor (rhodopsin)
light sensitive
for night vision in low light setting
less photon needed to elicit response thus daytime bleaches rods
cones:
responds to only certain wavelengths
blue, green, red, respond to 420,530,650 nM
3 photo receptors (iodopsin)
not light sensitive
for daytime vision (no cones=legally blind)
needs >100 photon to elicit response
21
Retinal conversion
only 1 million ganglion cells, over 94 rods/cones
rods:
high convergence=undetail
1 ganglion receives input from many rods
inc light gathering during night low light condition
inhibit spatial resolution (large receptive field)
no rods in fovea
cones:
low convergence=detailed
1:1 ganglion:cone
for acuity
spatial resolution (small receptive field)
almost all cones in fovea, few cones scattered too
22
Rods/Cones firing AP?
they don't fire AP
fire graded potentials (decay in time/space), (don't have enough sodium channels)
23
Ganglion cells in general
first cell in vision pathway to fire AP
axons of ganglion cell form optic nerve
projects to: LGN of thalamus, superior colliculus (retinofugal pathway), brainstem nuclei, suprachiasm nucleus of hypothalamus
24
Parasol vs Midget Cells
Parasol cells:
monochromatic
large cell bodies/receptive field
gross movement of stimulus
large fibers to LGN magnocellular layer (4cA)
Midget cells:
numerous
small cell bodies/receptive fields
fine detailed/color
small fibers to LGN parvocellular layer (4cB)
25
Normal path for visual perception
retina eye to LGN of thalamus to Visual cortex
info is divided at chiasm
shared at splenium
26
2 streams of info of vision
dorsal: tells us where
ventral: tells us what
27
Visual field affected by lesion
Optic nerve
Optic chiasm
Optic tract
Lower bank/meyer's loop
Upper bank/optic radiation
28
Most common eye symptom
double vision
other eye movement controlled by tectum
29
Intrinsic eye movement
iris spincter (parasymp of CN III)
pupillary dilator (ascending cervical sympth)
ciliary body (parasymp of CN III)
Vision of near object: ciliary body relaxes
Vision of far object : ciliary body contracts (bends lens to converge the divering light rays)
Dim light: pupillary dilator contract, iris sphinctor relax
Bright light: pupillary dilator relax, iris sphinctor contract
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