Sensory Pathways Flashcards

1
Q

what are the categories of sensory receptors?

A

mechanoreceptors
thermoreceptors
photoreceptors
chemoreceptors
nociceptors

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2
Q

where do Aalpha afferent fibers conduct signals from?

A

proprioceptors in muscle spindles and golgi tendon organs

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3
Q

where do Abeta afferent fibers conduct signals from?

A

non-noxious mechanoreceptors

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4
Q

what are the three major somatosensory tracts?

A

dorsal column medial lemniscal pathway
spinothalamic tracts
spinocerebellar tracts

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5
Q

what does a first-order neuron in a conscious pathway do?

A

delivers sensations to the CNS

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6
Q

where does the paleospinothalamic tract project to?

A

higher cortical areas (amygdala) to coordinate emotional aspect of pain

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7
Q

where does the spinomesencephalic tract project to?

A

periaqueductal gray

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8
Q

where does the spinoreticular tract project to?

A

reticular formation

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9
Q

what provides sensory innervation of the head?

A

all three branches of the trigeminal nerve (CN V)
external ear: CN VII, IX, X, spinal nerves C1 and C2

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10
Q

what controls the muscles of mastication?

A

proprioceptive afferents and motor efferents of the trigeminal

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11
Q

when does the vestibular system maintain balance?

A

forward movement
head rotation
tilting of the head or trunk

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12
Q

what are the compartments of the membranous labyrinth?

A

semicircular canals (3)
macula: utricle and saccule

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13
Q

firing is _____________ in the direction of the head movement

A

increased

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14
Q

where are cell bodies of bipolar vestibular neurons found?

A

within vestibular ganglion

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15
Q

where do some fibers from the optic nerve cross?

A

optic chiasm

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16
Q

where are olfactory receptors?

A

olfactory epithelium in upper nasal cavity

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17
Q

where do axons from the vomeronasal organ project to?

A

accessory olfactory bulb

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18
Q

what is the only sensory input with direct cortical innervation?

A

olfaction

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19
Q

what makes up superficial sensation?

A

touch
temperature
pain

20
Q

what is part of deep sensation?

A

proprioception
deep muscle pain
vibration

21
Q

where do Adelta fibers conduct signals from?

A

noxious mechanoreceptors for quick, intense pain

22
Q

what are the classic pain receptors?

A

nociceptors with C fibers

23
Q

what type of fibers are in the dorsal column medial lemniscal pathway?

A

Aalpha and Abeta

24
Q

what does the dorsal column medial lemniscal pathway conduct?

A

superficial sensation

25
Q

which fibers do the spinothalamic tracts utilize?

A

Adelta
C fibers

26
Q

how many neurons do conscious pathways require?

A

at least 3

27
Q

what is the path of the dorsal column medial lemniscal pathway?

A

dorsal horn, ascend ipsilaterally
synapse caudal medulla
ascend to contralateral thalamus via medial lemniscus
thalamus to ipsilateral somatosensory cortex

28
Q

lesions above the medulla will have signs that are on the ___________ side with conscious proprioception

A

contralateral

29
Q

what information do the spinothalamic tracts carry?

A

deep pressure
sharp pain
temperature

30
Q

why can pain caused by spinal nerve or cord damage in spinothalamic tracts be difficult to localize?

A

numerous interneurons, collaterals, and bilateral projections

31
Q

what are the indirect spinothalamic tracts?

A

paleospinothalamic
spinoreticular
spinomesencephalic

32
Q

what tracts are involved in unconscious proprioception?

A

spinocerebellar tracts

33
Q

where do the trigeminal touch, pain, and temperature pathways synapse?

A

pontine (touch) or spinal (pain and temperature) trigeminal nuclei

34
Q

what helps to maintain normal jaw function with unilateral damage?

A

bilateral projections to and from muscles of mastication

35
Q

where are hair cells concentrated?

A

ampulla

36
Q

if there is a lesion on one side, what do the hair cells do?

A

decrease firing on that side

37
Q

what bends the cilia of hair cells in the macula?

A

gravity

38
Q

damage to which areas would impact the visual pathway and the pupillary light reflex?

A

optic nerve
optic chiasm
optic tract

39
Q

what are the secondary sensory neurons of the olfactory system?

A

mitral cells

40
Q

where does the vomeronasal organ project to?

A

accessory olfactory bulb

41
Q

where is olfactory information transmitted to?

A

olfactory cortex
amygdala
hippocampus

42
Q

what types of fibers do spinal nerves contain?

A

both afferent and efferent fibers

43
Q

lesions below the medulla will have signs that are on the ___________ side with conscious proprioception

A

ipsilateral

44
Q

what is the trigeminal lemniscus?

A

where most fibers of the trigeminal (CN V) cross to synapse in the contralateral thalamus

45
Q

what is a lesion on one side of thee semi-circular canals interpreted as?

A

decreased activation on that side