Sensory Pathways

Question 1

what are the categories of sensory receptors?

Answer 1

mechanoreceptors
thermoreceptors
photoreceptors
chemoreceptors
nociceptors

Question 2

where do Aalpha afferent fibers conduct signals from?

Answer 2

proprioceptors in muscle spindles and golgi tendon organs

Question 3

where do Abeta afferent fibers conduct signals from?

Answer 3

non-noxious mechanoreceptors

Question 4

what are the three major somatosensory tracts?

Answer 4

dorsal column medial lemniscal pathway
spinothalamic tracts
spinocerebellar tracts

Question 5

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

Answer 5

delivers sensations to the CNS

Question 6

where does the paleospinothalamic tract project to?

Answer 6

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

Question 7

where does the spinomesencephalic tract project to?

Answer 7

periaqueductal gray

Question 8

where does the spinoreticular tract project to?

Answer 8

reticular formation

Question 9

what provides sensory innervation of the head?

Answer 9

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

Question 10

what controls the muscles of mastication?

Answer 10

proprioceptive afferents and motor efferents of the trigeminal

Question 11

when does the vestibular system maintain balance?

Answer 11

forward movement
head rotation
tilting of the head or trunk

Question 12

what are the compartments of the membranous labyrinth?

Answer 12

semicircular canals (3)
macula: utricle and saccule

Question 13

firing is _____________ in the direction of the head movement

Answer 13

increased

Question 14

where are cell bodies of bipolar vestibular neurons found?

Answer 14

within vestibular ganglion

Question 15

where do some fibers from the optic nerve cross?

Answer 15

optic chiasm

Question 16

where are olfactory receptors?

Answer 16

olfactory epithelium in upper nasal cavity

Question 17

where do axons from the vomeronasal organ project to?

Answer 17

accessory olfactory bulb

Question 18

what is the only sensory input with direct cortical innervation?

Answer 18

olfaction

Question 19

what makes up superficial sensation?

Answer 19

touch
temperature
pain

Question 20

what is part of deep sensation?

Answer 20

proprioception
deep muscle pain
vibration

Question 21

where do Adelta fibers conduct signals from?

Answer 21

noxious mechanoreceptors for quick, intense pain

Question 22

what are the classic pain receptors?

Answer 22

nociceptors with C fibers

Question 23

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

Answer 23

Aalpha and Abeta

Question 24

what does the dorsal column medial lemniscal pathway conduct?

Answer 24

superficial sensation

Question 25

which fibers do the spinothalamic tracts utilize?

Answer 25

Adelta
C fibers

Question 26

how many neurons do conscious pathways require?

Answer 26

at least 3

Question 27

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

Answer 27

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

Question 28

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

Answer 28

contralateral

Question 29

what information do the spinothalamic tracts carry?

Answer 29

deep pressure
sharp pain
temperature

Question 30

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

Answer 30

numerous interneurons, collaterals, and bilateral projections

Question 31

what are the indirect spinothalamic tracts?

Answer 31

paleospinothalamic
spinoreticular
spinomesencephalic

Question 32

what tracts are involved in unconscious proprioception?

Answer 32

spinocerebellar tracts

Question 33

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

Answer 33

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

Question 34

what helps to maintain normal jaw function with unilateral damage?

Answer 34

bilateral projections to and from muscles of mastication

Question 35

where are hair cells concentrated?

Answer 35

ampulla

Question 36

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

Answer 36

decrease firing on that side

Question 37

what bends the cilia of hair cells in the macula?

Answer 37

gravity

Question 38

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

Answer 38

optic nerve
optic chiasm
optic tract

Question 39

what are the secondary sensory neurons of the olfactory system?

Answer 39

mitral cells

Question 40

where does the vomeronasal organ project to?

Answer 40

accessory olfactory bulb

Question 41

where is olfactory information transmitted to?

Answer 41

olfactory cortex
amygdala
hippocampus

Question 42

what types of fibers do spinal nerves contain?

Answer 42

both afferent and efferent fibers

Question 43

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

Answer 43

ipsilateral

Question 44

what is the trigeminal lemniscus?

Answer 44

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

Question 45

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

Answer 45

decreased activation on that side