The obex is the part of the fourth ventricle that narrows down to become the ____________ ________.
central canal
Neurons on the surface of the obex are exposed to the cerebrospinal fluid in the _____ ____________.
4th ventricle
Neurons on the surface of the obex respond to toxins in the _________________ _________ in the 4th ventricle.
cerebrospinal fluid
The group of neurons on the ___________ of the ________ that responds to toxins in the cerebrospinal fluid is called the area postrema
walls
obex
Neurons in the ________ _____________ detect toxins in the cerebrospinal fluid.
area postrema
Neurons in the area postrema project to the preganglionic parasympathetic neurons in the _________ _________ __________ of the ________ __________ that control the muscles of the stomach
dorsal motor nucleus
vagus nerve
When they detect toxins in the cerebrospinal fluid neurons in the area postrema initiate vomiting through their projections to the _________ _________ ___________ of the ________ __________.
dorsal motor nucleus
vagus nerve
The area _____________ is sometimes called the vomiting center.
postrema
The lateral and anterior spinothalamic tracts carry ________________ sensations through the lateral region of the medulla without synapsing.
protopathic
Axons in the spinothalamic tracts synapse only in the _____________.
thalamus
The axons in the fasciculus gracilis and fasciculus cuneatus synapse on ____ in the nucleus gracilis and nucleus cuneatus in the lower medulla
second order neurons
Just as the fasciculus cuneatus is __________ to the fasciculus gracilis, the nucleus cuneatus is ___________ to the nucleus gracilis.
lateral
lateral
The axons of the __________ _________ neurons in the nucleus gracilis run ventrad in wide arcs as internal arcuate fibers.
secondary sensory
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.
nucleus gracilis
The axons of the neurons in the left nucleus gracilis form the ventral half of the ________ _________ _______________ after they cross the midline.
right medial lemniscus
The axons of the neurons in the nucleus gracilis are _____________ __________ __________ until they cross the midline.
internal arcuate fibers
Internal arcuate fibers make a right angle turn rostrad toward the thalamus when they enter the _________ ______________.
medial lemniscus
The ventral half of the left medial lemniscus carries _____________ information from the _________ _________ extremity to the thalamus.
epicritic
right lower
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.
secondary sensory
Axons in the ventral half of the medial lemniscus come from neurons in the _________ __________ and carry epicritic information from the contralateral _________ ____________.
nucleus gracilis
lower extremity
Axons in the dorsal half of the medial lemniscus come from neurons in the _________ __________ and carry epicritic information from the contralateral _________ ____________.
nucleus cuneatus
upper extremity
When axons from the nucleus cuneatus cross the midline they are __________ to axons from the nucleus gracilis.
dorsal
Internal arcuate fibers from the nucleus cuneatus must _________ internal arcuate fibers from the nucleus gracilis before crossing the ____________.
cross
midline
In the medulla each medial lemniscus is a vertical ribbon of white matter on the __________ side of a pyramid.
dorsal
Tracts are _________ matter; nuclei are _________ matter; but myelinated tracts usually stain black with silver, iron, or osmium, and nuclei usually do not take these metallic stains.
tracts: white
nuclei: gray
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.
decussation
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 ______________.
decussation
The nucleus gracilis and nucleus cuneatus continue to contribute to the medial lemniscus up to the level of the __, but the fasciculus ___ disappears by that level.
middle medulla
gracilis
The nucleus gracilis is on the dorsal surface of the ___________ at the mid-medulla level
medulla
The nucleus cuneatus is still deep to the _____________ ___________ lateral to the nucleus gracilis at the mid-medulla level.
fasciculus cuneatus
The medial lemniscus contacts the posterior surface of the _____________ throughout the medulla
pyramid
The posterior spinocerebellar tract drifts from its position on the _________ side of the lower medulla to a dorsolateral position at the mid-medulla level.
lateral
The lateral cuneate nucleus becomes prominent dorsolateral to the nucleus __________ and deep to the posterior spinocerebellar tract at the mid-medulla level
cuneatus
The cuneocerebellar tract merges with the ____________ _________________ tract to form the restiform body at the mid-medulla level.
posterior spinocerebellar
The bulge on the lateral side of the middle and upper medulla is called the __________.
olive
The inferior olivary nucleus is wavy ribbon of _________ matter inside the olive
gray
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.
spino-olivary tract
The central tegmental tract carries messages from the _______ ___________ of the ____________ to the ipsilateral ____________ __________ __________ of the ___________.
red nucleus
midbrain
inferior olivary nucleus
medulla.
It is a bit unfortunate that the tract that should have been called the rubro-olivary tract is called the __________ _______________ ________.
central tegmental tract
The central tegmental tract enters the _____________ __________ ___________ on its dorsal (or posterior surface.
inferior olivary nucleus
The spino-olivary tract enters the inferior olivary nucleus on its ____ side
convex lateral
The spino-olivary tract tells the ____________ __________ __________ how an action was carried out.
inferior olivary nucleus
The central tegmental tract tells the _____________ _________ __________ what the action was intended to be .
inferior olivary nucleus
The ___________ _________ __________ compares intention and action and communicates that comparison to the contralateral cerebellum.
inferior olivary nucleus
Information from the inferior olivary nucleus allows the contralateral _____________ to better assist the ipsilateral cerebral cortex the next time the action is performed.
cerebellum
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 ___________ ______________ _________.
central tegmental tract
The cerebellum to ______ __________ to _____________ ________ _________ to cerebellum circuit is responsible for the simpler aspects of motor learning
red nucleus
inferior olivary nucleus
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
left
left
right.
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 ____________ __________ __________.
red nucleus
inferior olivary nucleus
The inferior olivary nucleus projects to the contralateral side of the ____________ through the restiform body.
cerebellum
The olivocerebellar tract leaves the medial side of the inferior olivary nucleus and joins the contralateral ____________ _______.
restiform body
The restiform body is formed by the union of the ________________ ________, the posterior spinocerebellar tract, and the cuneocerebellar tract.
olivocerebellar tract
The olivocerebellar tract curves dorsad to join the _____________ ____________________ _______ and cuneocelebellar tract to form the restiform body.
posterior spinocerebellar tract
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.
inferior olivary
central tegmental tract
The medullary reticular formation contains neurons whose axons form the __________ _____________________ _________.
lateral reticulospinal tract
The most easily assigned function of the medullary reticular formation is the stimulation of the lower motor neurons for the ___________ of the _________ ____________ during absent-minded walking.
flexion
lower extremity
Most of the other ___________ in the medullary reticular formation have short axons that create a neural network.
neurons
The neural network of the _____________ formation gets its name from the Latin word for net: reticulum.
reticular
The neural network of the _____________ formation gets its name from the Latin word for net: reticulum.
reticular
The nucleus ambiguus is embedded in the ________________ ________________ ventromedial to the ___________ ___________________ nucleus.
reticular formation
spinal trigeminal
The inferior olivary nucleus is _______________ to the reticular formation
ventral (or anterior)
The inferior olivary nucleus projects to the ________________ side of the cerebellum via the ________________ _________.
contralateral
restiform body
The inferior olivary nucleus receives information from the _______ ____________ of the midbrain via the _____________ __________________ ____________.
red nucleus
central tegmental tract
The red nucleus receives information from the __________________ side of the cerebellum via the _____________ ______________ ______________.
contralateral
superior cerebellar peduncle
The medial lemniscus is ____________ to the inferior olivary nucleus
medial
Each medial lemniscus carries _____________ information from the ___________________ side of the body to the ______________.
epicritic
contralateral
thalamus