Chapter 24: Medulla Flashcards

1
Q

The obex is the part of the fourth ventricle that narrows down to become the _____.

A
  • Central canal
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2
Q

Neurons on the surface of the obex are exposed to the cerebrospinal fluid in the _____.

A
  • 4th ventricle
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3
Q

Neurons on the surface of the obex respond to toxins in the _____ in the 4th ventricle.

A
  • Cerebrospinal fluid
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4
Q

The group of neurons on the _____ that responds to toxins in the cerebrospinal fluid is called the area postrema.

A
  • Walls of the obex
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5
Q

Neurons in the _____ detect toxins in the cerebrospinal fluid.

A
  • Area postrema
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6
Q

Neurons in the area postrema project to the preganglionic parasympathetic neurons in the _____ of the _____ that control the muscles of the stomach.

A
  • Dorsal motor nucleus

- Vagus nerve

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7
Q

When they detect toxins in the cerebrospinal fluid neurons in the area postrema initiate vomiting through their projections to the _____ of the _____.

A
  • Dorsal motor nucleus

- Vagus nerve

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8
Q

The _____ is sometimes called the vomiting center.

A
  • Area postrema
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9
Q

The lateral and anterior spinothalamic tracts carry _____ sensations through the lateral region of the medulla without synapsing.

A
  • Protopathic
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10
Q

Axons in the spinothalamic tracts synapse only in the _____.

A
  • Thalamus
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11
Q

The axons in the _____ and _____ synapse on second order neurons in the nucleus gracilis and nucleus cuneatus in the lower medulla.

A
  • Fasciculus gracilis

- Fasciculus cuneatus

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12
Q

Just as the fasciculus cuneatus is _____ to the fasciculus gracilis, the nucleus cuneatus is _____ to the nucleus gracilis.

A
  • Lateral

- Lateral

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13
Q

The axons of the _____ neurons in the nucleus gracilis run ventrad in wide arcs as internal arcuate fibers.

A
  • Secondary sensory
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14
Q

Internal arcuate fibers from each _____ cross in the midline just dorsal to the pyramids and turn rostrad to form the ventral half of the contralateral medial lemniscus.

A
  • Nucleus gracilis
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15
Q

The axons of the neurons in the left nucleus gracilis form the ventral half of the _____ after they cross the midline.

A
  • Right medial lemniscus
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16
Q

The axons of the neurons in the nucleus gracilis are _____ until they cross the midline.

A
  • Internal arcuate fibers
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17
Q

Internal arcuate fibers make a right angle turn rostrad toward the thalamus when they enter the _____.

A
  • Medial lemniscus
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18
Q

The ventral half of the left medial lemniscus carries _____ information from the _____ extremity to the thalamus.

A
  • Epicritic

- Right lower

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19
Q

Axons of _____ neurons in the nucleus cuneatus run ventrad in wide arcs, cross the midline, and turn rostrad to form the dorsal half of the medial lemniscus.

A
  • Secondary sensory
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20
Q

Axons in the ventral half of the medial lemniscus come from neurons in the _____ and carry epicritic information from the contralateral _____.

A
  • Nucleus gracilis

- Lower extremity

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21
Q

Axons in the dorsal half of the medial lemniscus come from neurons in the _____ and carry epicritic information from the contralateral _____.

A
  • Nucleus cuneatus

- Upper extremity

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22
Q

When axons from the nucleus cuneatus cross the midline they are _____ to axons from the nucleus gracilis.

A
  • Dorsal
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23
Q

Internal arcuate fibers from the nucleus cuneatus must _____ internal arcuate fibers from the nucleus gracilis before crossing the _____.

A
  • Cross

- Midline

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24
Q

In the medulla each medial lemniscus is a vertical ribbon of white matter on the _____ side of a pyramid.

A
  • Dorsal
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25
Q

Tracts are _____; nuclei are _____; but myelinated tracts usually stain black with silver, iron, or osmium, and nuclei usually do not take these metallic stains.

A
  • White matter

- Gray matter

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26
Q

A decussation is a crossing of right and left tracts en route from one level to another. Thus, the crossing of internal arcuate fibers to form the medial lemniscus is the _____ of the medial lemniscus.

A
  • Decussation
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27
Q

Fibers crossing from one side of the CNS to the other at the same level form a commissure; fibers crossing from one side to the other en route to a different level form a _____.

A
  • Decussation
28
Q

The nucleus _____ and nucleus _____ continue to contribute to the medial lemniscus up to the level of the middle medulla, but the fasciculus gracilis disappears by that level.

A
  • Gracilis

- Cuneatus

29
Q

The nucleus gracilis is on the dorsal surface of the _____ at the _____ level.

A
  • Medulla

- Mid-medulla

30
Q

The nucleus cuneatus is still deep to the _____ lateral to the nucleus gracilis at the mid-medulla level.

A
  • Fasciculus cuneatus
31
Q

The medial lemniscus contacts the posterior surface of the _____ throughout the medulla.

A
  • Pyramid
32
Q

The posterior spinocerebellar tract drifts from its position on the _____ side of the lower medulla to a dorsolateral position at the mid-medulla level.

A
  • Lateral
33
Q

The lateral cuneate nucleus becomes prominent dorsolateral to the nucleus _____ and deep to the posterior spinocerebellar tract at the mid-medulla level.

A
  • Cuneatus
34
Q

The cuneocerebellar tract merges with the _____ tract to form the restiform body at the mid-medulla level.

A
  • Posterior spinocerebellar
35
Q

The bulge on the lateral side of the middle and upper medulla is called the _____.

A
  • Olive
36
Q

The inferior olivary nucleus is wavy ribbon of _____ inside the olive.

A
  • Gray matter
37
Q

The inferior olivary nucleus receives tendon stretch information from the contralateral side of the body through the _____ and messages from the ipsilateral red nucleus of the midbrain through the central tegmental tract.

A
  • Spino-olivary tract
38
Q

The central tegmental tract carries messages from the _____ of the _____ to the ipsilateral _____ of the _____.

A
  • Red nucleus
  • Midbrain
  • Inferior olivary nucleus
  • Medulla
39
Q

It is a bit unfortunate that the tract that should have been called the rubro-olivary tract is called the _____.

A
  • Central trigeminal tract
40
Q

The central tegmental tract enters the _____ on its dorsal (posterior) surface.

A
  • Inferior olivary nucleus
41
Q

The spino-olivary tract enters the _____ on its convex lateral side.

A
  • Inferior olivary nucleus
42
Q

The spino-olivary tract tells the _____ how an action was carried out.

A
  • Inferior olivary nucleus
43
Q

The central tegmental tract tells the _____ what the action was intended to be.

A
  • Inferior olivary nucleus
44
Q

The _____ compares intention and action and communicates that comparison to the contralateral cerebellum.

A
  • Inferior olivary nucleus
45
Q

Information from the inferior olivary nucleus allows the contralateral _____ to better assist the ipsilateral cerebral cortex the next time the action is performed.

A
  • Cerebellum
46
Q

The contralateral cerebellum will inform the ipsilateral red nucleus of its intentions and the red nucleus will inform the ipsilateral inferior olivary nucleus of those intentions through the _____.

A
  • Central tegmental tract
47
Q

The cerebellum to _____ to _____ to cerebellum circuit is responsible for the simpler aspects of motor learning.

A
  • Red nucleus

- Inferior olivary nucleus

48
Q

The right side of the cerebellum projects to the _____ red nucleus which projects to the _____ inferior olivary nucleus which projects to the _____ side of the cerebellum.

A
  • Left
  • Left
  • Right
49
Q

The body part whose performance is subject to the cerebellar learning circuit is ipsilateral to the participating side of the cerebellum but contralateral the participating _____ and _____.

A
  • Red nucleus

- Inferior olivary nucleus

50
Q

The inferior olivary nucleus projects to the contralateral side of the _____ through the restiform body.

A
  • Cerebellum
51
Q

The olivocerebellar tract leaves the medial side of the inferior olivary nucleus and joins the contralateral _____.

A
  • Restiform body
52
Q

The restiform body is formed by the union of the _____ tract, the posterior spinocerebellar tract, and the cuneocerebellar tract.

A
  • Olivocerebellar
53
Q

The olivocerebellar tract curves dorsad to join the _____ and cuneocelebellar tract to form the restiform body.

A
  • Posterior spinocerebellar tract
54
Q

The region ventral to the hypoglossal nucleus, dorsal motor nucleus of the vagus, and solitary nucleus and dorsal to the _____ nucleus and _____ is the reticular formation of the medulla.

A
  • Inferior olivary nucleus

- Central tegmental

55
Q

The medullary reticular formation contains neurons whose axons form the _____.

A
  • Lateral reticulospinal tract
56
Q

The most easily assigned function of the _____ is the stimulation of the lower motor neurons for the _____ of the _____ during absent-minded walking.

A
  • Medullary reticular formation
  • Flexion
  • Lower extremity
57
Q

Most of the other _____ in the medullary reticular formation have short axons that create a neural network.

A
  • Neurons
58
Q

The neural network of the _____ gets its name from the Latin word for net: reticulum.

A
  • Reticular formation
59
Q

The nucleus ambiguus is embedded in the _____ ventromedial to the _____ nucleus.

A
  • Reticular formation

- Spinal trigeminal

60
Q

The inferior olivary nucleus is _____ to the reticular formation.

A
  • Ventral (anterior)
61
Q

The inferior olivary nucleus projects to the _____ side of the cerebellum via the _____.

A
  • Restiform body
62
Q

The inferior olivary nucleus receives information from the _____ of the midbrain via the _____.

A
  • Red nucleus

- Central tegmental tract

63
Q

The red nucleus receives information from the _____ side of the cerebellum via the _____.

A
  • Contralateral

- Superior cerebellar peduncle

64
Q

The medial lemniscus is _____ to the inferior olivary nucleus.

A
  • Medial
65
Q

Each medial lemniscus carries _____ information from the _____ side of the body to the _____.

A
  • Epicritic
  • Contralateral
  • Thalamus