Neuro.block 3 Part 1

Front 1

The CNS interprets the type of sensation by the type of receptor and the sensory ganglion cell conducting the potentials. This is called a _

Back 1

population code.

Front 2

Together, frequency and population codes provide a transduction of both _ and _

Back 2

sensation type and magnitude

Front 3

The frequency code determines the _. It is composed of the _ and _

Back 3

magnitude of the stimulus.

Coded by the frequenct of APs and the number of axons producing the AP

Front 4

The _ range is the range of intensity of stimulus over which a receptor or its neuron will respond after reaching threshold.

Back 4

dynamic

Front 5

Dynamic range and differing threshold sensitivities of particular receptors provide another mechanism to code the magnitude of a stimulus through _

Back 5

a process of successive recruitment.

Front 6

Rapidly adapting and low threshold receptors are used in _

Back 6

tactile sensations such as those of the dorsal columns

Front 7

_ and _ are used in tactile sensations such as those of the dorsal columns

Back 7

rapidly adapting and low threshold receptors

Front 8

The dorsal columns carry the primary sensations of epicritic (discriminative) touch, vibration, and proprioception or position sense. How is it these sensations are perceived as separate?

Back 8

through the use of different types of peripheral receptors

Front 9

Cutaneous tactile receptors are located in glabrous and hairy skin. These are typically _-threshold _receptors.

Back 9

low threshold mechanoreceptors

Front 10

Meissner and Pacinian corpuscles are _ _ and can detect transient stimuli such as events and motion.

Back 10

rapidly adapting

Front 11

Meissner corpuscles are part of detection of _ with Merkel complexes.

Pacinian corpuscles detect _

Back 11

texture

vibration

Front 12

Merkel cell complexes, and Ruffini endings are_and can detect _ and _

Back 12

slowly adapting

position and movement (as well as temp)?

Front 13

The _ determines the discriminative ability of the area.

Back 13

size of the receptive fields

Front 14

The sequential activation of receptive fields can yield _

Back 14

the detection of motion, its velocity and direction of a stimulus.

Front 15

The dorsal column nuclei are also the first level at which _ can influence the _

Back 15

descending inputs (primarily from the contralateral somatosensory cortex and reticular formation)

incoming sensory information.

Front 16

The _ for tactile information from the face uses similar receptors as in the dorsal column medial-lemniscal system

Back 16

trigeminal system

Front 17

For tactile information and proprioception, the _ and _ are the counterparts of the dorsal column nuclei.

Back 17

the principal (aka proper, chief) sensory nucleus

mesencephalic nucleus

Front 18

The _ is an exception to the rule that first order primary sensory neurons are not located in the CNS.

Back 18

mesencephalic nucleus of V

* It carries the modalities of proprioception to jaw muscles, and other muscles of the face

Front 19

The ventral posterolateral and ventral posteromedial nuclei of the thalamus project through the _ and the _ in a somatotopic pattern to cerebral cortex on the postcentral gyrus

Back 19

internal capsule

superior thalamic peduncle

Front 20

Area _ of the somatosensory cortex receives information from cutaneous receptors related to the size, shape and texture of an object.

Back 20

3b

It also provides discrimination as to which finger contacts an object.

Front 21

Area 3b of the somatosensory cortex recieves information from _ regarding...

Back 21

cutaneous receptors, regarding the size, shape, and texture of an object.

Front 22

_ responds to the texture of an object detected by multiple fingers.

Back 22

Area 1

Front 23

Which area provides discrimination as to which finger contacts an object

Back 23

3b of somatosensory cortex

Front 24

Secondary Somatosensory cortex is found _, and is responsible for _

Back 24

on the inner face of the lateral fissure beneath the face representation

It receives input from both sides and is responsible for permitting a discriminative task that is learned by one hand to be performed by the other.

Front 25

Sensory cortex is capable of considerable plasticity in its representation of receptive fields. This is primarily due to _

Back 25

the extensive cross innervation between areas of receptive fields.

Front 26

Protopathic sensations are conveyed through the _ system

Back 26

anterolateral

These sensations include nondiscriminative touch, thermal sensation, and pain.

Front 27

Protopathic axons that are thinly myelinated can be called _, and unmyelinated fibers are called _.

Back 27

A Delta

C fibers

Front 28

Nerve pressure blocks or anoxia preferentially affects _.

Local anesthetics such as lidocaine or bupvacaine preferentially affect _

Back 28

large diameter heavily myelinated fibers, (resulting in varying loss of epicritic touch, vibratory and postural sensation.)

smaller diameter Aδ and C-fibers (resulting in a loss of nociception or analgesia)

Front 29

Free nerve ending receptors are broadly classified into _ and _

Back 29

nociceptors- (pain receptors) - which are further divided into A delta mechanical and C polymodal

... and innocuous-(non-noxious) receptors.

Front 30

Chemonociceptors respond to substances such as _, _, and _

Back 30

bradykinin, H ions, and foreign irritants like insect venoms

Front 31

Innocuous receptors are _ threshold mechanoreceptors, that respond to _ stimuli.

Back 31

high

rough (tapping, squeezing, rubbing)

They are silent in absence of stimuli and respond for the duration of the stimuli

Front 32

What is an axon reflex?

Back 32

When tissue damage occurs, a flare response (redness/swelling) spreads outside the area of injury. This causes release of intermediaries such as substance P that will activated mast cells

Front 33

Secondary hyperalgesia occurs in areas _and is thought to result from _

Back 33

adjacent to the tissue damage

changes in the CNS.

Front 34

_ is when dorsal horns near damaged tissue lower their threshold and acquire larger receptive fields. This is the result of long term action of the metabotropic receptors and second messenger systems.

Back 34

Central Sensitization

Front 35

Central Sensitization can be severe enough that it causes _, which is when normally innocuous stimuli evokes pain.

Back 35

allodynia

Front 36

A small number of protopathic C fibers enter the ventral root (instead of dorsal), particularly from the _

Back 36

pelvic viscera

Front 37

The two primary pathway types of the anterolateral system are described as direct (_)and indirect (_). Direct going from the spinal cord -> _ -> _. And Indirect going from the spinal cord -> _ -> _ ->_.

Back 37

(neospinothalamic)
(paleospinothalamic)

Direct: spinal cord-thalamus -cortex
Indirect: spinal cord-reticular formation-thalamus -broad regions of cortex

Front 38

The reticular formation cortical projections are believed to subserve an _ function of pain, and may be responsible for the _ sensations after thalamic lesion

Back 38

alerting

dull, poorly localized and persistent painful

Front 39

Outside of the primary anterolateral tracts, the _system is an ipsilateral projection of the dorsal horn in the lateral funiculus to end in the lateral cervical nucleus located from C1-C3

Back 39

spinocervicothalamic

Front 40

The protopathic sensation from the face are processed primarily through the _ nuclei, with protopathic touch processed primarily through the_ and _, and pain through the _

Back 40

spinal trigeminal

pars oralis and interpolaris

pars caudalis

Front 41

Although there are parallel pathways, cerebral cortex and hypothalamus modulate the periaqueductal gray through _ pathways. These exert an excitatory influence on the serotinergic pathways of the nucleus raphe magnus.

Back 41

enkephalinergic

Front 42

Localizable pain sensation is most likely to be carried in which tract?

Back 42

neospinothalamic tracts

Front 43

Which receptor type would be expected to respond to bradykinin released as a result of tissue damage

Back 43

chemonocioceptors

Front 44

The lateral division of the dorsal root entry zone including both noxious and innocuous sensation projects to_

Back 44

Lamina I (the posteromarginal nucleus)

Front 45

What tract is responsible for the return of pain sensation after anterolateral tract lesions?

Back 45

Spinocervicothalamic tracts

Front 46

Enkephalinergic pathways exert a(n) _ influence on the serotinergic pathways of the _.

Back 46

excitatory

nucleus raphe magnus

Front 47

The nucleus raphe magnus projects to the spinal trigeminal nucleus and on spinal cord dorsal horn enkephalinergic interneurons in _ and _ that are capable of directly inhibiting nociceptive inputs pre and postsynaptically.

Back 47

lamina II and III

Front 48

Endolymph is found in the _ and is secreted by _

Back 48

lumen of the cochlear duct
the stria vascularis

Endolymph is similar to intracellular fluid, in that it is high in K

Front 49

Sound frequency is coded in the cochlea such that high frequencies ...

Back 49

Stimulate hair cells in basal areas of the cochlea

Front 50

Normal conversation is in the range of _ to _ Hz, and is about _ db.

Back 50

2000-4000 Hz

50 dB

Front 51

Otosclerosis causes _, in this case, the _ becomes fused with the _.

Back 51

conduction deafness
stapes, oval window.

This brings the level of normal conversation to a whisper

Front 52

The cochlea is the spiral portion of the bony and membranous labyrinths. It makes 2.5 turns around a bony core, the _

Back 52

modiolus

Front 53

The spaces between the bony labyrinth and the membranous labyrinth form two chambers the_ and _,

Back 53

scala tympani and scala vestibuli

Front 54

The scala tympani and scala vestibuli are separated by the _membrane and _ membrane from the lumen of the membranous labyrinth.

Back 54

basilar
Reissner’s

Front 55

The scala vestibuli and typani are filled with _

Back 55

perilymph (similar to CSF, high in Na)

Front 56

The cochlear duct contains a primary sensory transducer for sound, the _. This supplies the mechanism for the transduction of sound into action potentials

Back 56

the organ of Corti

Front 57

Regarding transduction of sound: Sound waves in cochlear fluid cause the _ to vibrate, the _ rubs against the _ of the hair cells, depolarizing them.

Back 57

basilar membrane

tectoral membrane

stereocilia

Front 58

The resonance at _ frequencies activates hair cells near the base of the cochlea while _ frequencies activate hair cells near the apex

Back 58

high

low

Front 59

Volume of sound is encoded by two primary mechanisms, what are they?

Back 59

Neuron threshold and saturation
Neuron type

Front 60

The type of neuron and hair cell also contribute to _ and _.

Back 60

volume coding and detection

Front 61

Inner hair cells are used as _ detectors.
Outer hair cells are _ detectors

Back 61

primary frequency detectors (they receive most afferent innervation)

low intensity sound detectors that are less specific. (receive most innervation from efferent cochlear bundle)

Front 62

Recent data suggest that outer hair cells may act as_ through their contractile and electrical properties.

Back 62

selective amplifiers

Front 63

Olivocochlear axons are associated with _

Back 63

auditory sharpening, the ability to focus on particular sounds and frequencies within a complex pattern of input.

Front 64

Patient has loss of high frequency hearing, but frequencies below 4000 Hz were spared. Peripheral branches of type I primary afferents originated from which part of the spiral ganglion were spared?
The damaged afferents normally end in _

Back 64

Inner hair cells toward the apex of the cochlea

Anterior and Posterior cochlear nuclei

Front 65

The cochlea is organized such that high frequencies are represented at the _ and low frequencies more toward the _

Back 65

base,

apex

Front 66

Primary afferent fibers from the _ ganglion make up the cochlear portion of the vestibulocochlear nerve.

Back 66

spiral

Front 67

An ischemic infarction results in total deafness in only the right ear. What artery is most likely involved?

Back 67

right anterior inferior cerebellar artery. It supplies the cochlear nuclei, vestibulocochlear nerve, and the cochlea itself

Front 68

What are characteristics of the fibers entering the medial division of the posterior root?

Back 68

Heavily myelinated, rapidly conducting, subserve vibratory sense, two-point discrimination and proprioception

Front 69

Lightly myelinated fibers conveying pain and thermal information collect to form the _ division of the posterior root.

Back 69

lateral

Front 70

The pars caudalis nucleus receives afferents from the _ side of the face conveying _

Back 70

contralateral

pain and thermal sensation

Front 71

The NT involved in the primary central auditory pathways is _ or _

Back 71

glutamate or aspartate

Front 72

Auditory information is organized tonotopically as well as into two types of parallel pathways, _ information and _ information

Back 72

monaural information that is routed to the contralateral side
binaural information that is used to compare differences in sounds that reach both ears.

Front 73

The _ nucleus is the first level of processing for the localization of sound in the auditory fields.

Back 73

superior olivary nucleus

Front 74

The medial division of the _ is anatomically organized so that signals from the ipsilateral and contralateral ear can be compared in time to localize the sound.

Back 74

superior olivary nuclei

Front 75

The lateral division of the superior olivary complex contributes to _ as well as compares _. It is particularly effective to _ frequency signals

Back 75

sound localization (by phase comparison)

sound intensity difference between ears

high

Front 76

Monaural projections that bypass the superior olive cross the midline in the_

Back 76

dorsal (posterior) acoustic stria.

Front 77

The _ projects to the _ of the thalamus via the inferior brachium

Back 77

inferior colliculus projects to the medial geniculate nucleus

Front 78

Regarding the medial geniculate nucleus:
The anterior division responds to _, it projects to the _ The posterior division conveys information about _, and it projects to the _

Back 78

more complex sound patterns, primary auditory cortex.

moving or novel stimuli, secondary auditory cortex.

Front 79

The medial division of the medial geniculate responds to a wide range of frequencies. It projects to _; it may act as part of the _

Back 79

temporal and parietal association areas, the amygdala and parts of the basal ganglia;

reticular formation

Front 80

The medial geniculate projects to auditory cortex via the _

Back 80

retrolenticular portion of the posterior limb of the internal capsule.

Front 81

Primary auditory cortex is located in the_located in the depths of the lateral fissure.

Back 81

transverse gyri of Heschl

Front 82

Wernicke’s area is connected to primary auditory cortex via the _

Back 82

arcuate fasciculus.

Front 83

The middle ear reflex involves CN _ and _ as the efferent arm, where as the afferent arm is provided by _ and _

Back 83

VII (stapedius) and V (tensor tympani).

Cochlear nuclei and superior olive

This is sound dampening.