Olfaction & visual systems Flashcards

(48 cards)

1
Q

olfactory pathway

A

Up through cribriform plate → olfactory bulb → olfactory tract → olfactory cortical areas
**No relay through the thalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

general brain parts/functions

A

hippocampus - memory
hypothalamus - homeostasis/autonomic response
amygdala and limbic - emotion
epithalamus - coordination
ventral striatum - decision making and reward-related behavior
entorhinal cortex: connects memories and smells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

medial geniculate nucleus

lateral geniculate nucleus

A
medial = hearing
lateral = vision
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

VPM

A

somatic sensation for face/head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

VPL

A

somatic sensation for the rest of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

fracture of anterior cranial fossa - anosmia

A

lack of smell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

fracture of anterior cranial fossa - CSF rhinorrhea

A

Leakage of CSF from subarachnoid space into nasal cavity

Route for bacteria to enter brain - can cause infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

type of receptor cells present in olfactory system

A

Specialized bipolar neurons (1st order neurons)

Chemoreceptors / Exteroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

location of receptor cells in olfactory system

A

Located in mucous membrane in nasal cavity
Hairs/cilia react to odors
NO relay through thalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

constant turnover of cells

A

replaced every 60 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

functions of visual system

A

Focus images on back of retina
Adjust dark/light intensity; different degrees of light
Color detection
Shape and movement detection (processing)
Localize visual stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

orbit

A

Socket: contains eyeball, blood vessels, nerves

Fractures cause visual disturbances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

eyelids

A

Protect eyes
Orbicularis oculi – closes eylid (CN VII)
Lesion in nerve or facial motor nucleus in pons (Bell’s Palsy) leads to inability to close eyelid
Levator palpebrae superioris – opens eyelid (CN III)
Lesion in nerve or oculomotor nucleus in midbrain leads to Ptosis (drooping eyelid due to weakness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lacrimal Glands

A

Keep eye lubricated (produce tears)
Innervated by CN VII
Lesion to nerve or motor nuclei can result in inability to tear/dry eye (BP)
Puts cornea at risk with foreign objects entering eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Eyeball - cornea

A

Light refraction and focusing image
Sensory innervation by CN V
Reflex by CN V (afferent, brainstem to facial motor n.) and CN VII (efferent, to orbicularis oculi)
Lesions in CN V, CN VII, or facial motor nucleus in pons will impair/lose corneal blink reflex to touch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Eyeball - iris

A
Pupil is hole in iris that constricts and dilates in response to light
Parasympathetic Innervation
cell bodies of neurons in Edinger Westphal nucleus in midbrain
Axons leave midbrain in CN III
Action = constrict pupil
Lesion – dilated pupil
Sympathetic Innervation
Dilates pupil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Eyeball - Ciliary body

A

Change shape for proper focus (smooth muscle attach to lens – contract and change)
Ciliary muscles innervated be Edinger-Westphal nucleus in midbrain (CN III)
Important in focusing image for looking at close objects
Lesions: difficulty focusing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Eyeball - photoreceptors

A

Sit in retina
Rods: highly sensitive to light for night vision; no color (monochromatic); do not help with visual acuity
Cones: for colors (trichromatic) and visual acuity; low sensitivity to light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

corneal blink reflex

A

Blink reflex is a protective mechanism in response to touch
When something is touching eye, CN V sends signal to brainstem to facial motor nucleus
CN VII transmits signal to the orbicularis oculi and you blink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how corneal blink reflex can be lost

A

Can be lost due to lesions to CN V or CN VII or their nuclei

21
Q

vision pathway

A

Light through cornea → Lens → Retina → Photo receptors → Ganglion Cells → Optic Nerve → Optic Chiasm → Optic Tract → Lateral Geniculate Nucleus → Optic Radiation → Primary Visual Cortex

22
Q

lesion in optic nerve

A

ipsilateral blindness (blind in that eye)

23
Q

lesion in optic chiasm

A

Tunnel Vision: cuts off nasal retinas so we lose peripheral vision

24
Q

lesion in optic tract

A

ipsilateral temporal retina, contralateral nasal retina and visual field, homonymous hemianopsia

25
lesion in visual cortex
cortical blindness (partial or complete)
26
left visual field
nasal retina from left eye, temporal retina from right eye
27
right visual field
nasal retina from right eye, temporal retina from left eye
28
to have complete perspective of L/R visual fields you have to ...
get information from both eyes
29
hypermetropia
farsighted - cannot focus well on near objects - caused by misshapen lens or cornea or eyeball sizes and shapes that produce refractive errors.
30
myopia
nearsighted - cannot focus well on far away objects - caused by misshapen lens or cornea or eyeball sizes and shapes that produce refractive errors.
31
presbyopia
reduction in visual acuity due to aging in which individuals have trouble focusing on near objects
32
cataracts
age-induced | clouds the lens reducing vision in the eye
33
glaucoma
due on an increase in intra-ocular pressure which damages the retina; early sign is tunnel vision
34
macular degeneration
familial
35
saccades
rapid movement of the eye between fixation points
36
components of saccades
the oculomotor system: moves the eyes in the orbits | head-movement system: moves the eye sockets
37
visual association cortex (PCA) is responsible for
association: needs info to tell you what you are seeing object agnosias and prospoagnosias
38
limbic system is responsible for
emotional responses to light | seasonal affective disorder
39
CN VII (facial) is responsible for
blink in response to light | another form of blink reflex where the stimuli to blink is light rather than touch
40
superior colliculus and the spinal cord is responsible for
Visual discrimination and integration occur in superior colliculus with somatosensory and auditory input to help orient eyes motor response of head and body in response to visual input
41
hypothalamus is responsible for
circadian rhythms
42
Pretectum and Edinger Westphal Nucleus (CNIII) is responsible for
constricting pupil in response to light
43
visual fields are made up of
nasal and temporal retina
44
focal point
far side of each eye and medial corner of each eye
45
lesion in optic radiation
similar to tract but bigger section so less of an impact; partial visual field loss
46
pupillary light reflex
shine light in one eye, both pupils restrict | light received by Edinger Westphal nucleus (acc. to oculomotor n) → ciliary ganglion → pupils constrict
47
frontal eye field
NOT the same as visual field portion of the brain that helps control the direction eyes move lesion: eyes drift in the direction of the lesion
48
PPRF (paramedian pontine reticular formation) and lesion
segment of brainstem that helps coordinate abducens and oculomotor nuclei lesion: eyes drift to opposite side