Chapter 24: Medulla Flashcards
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 _____ that responds to toxins in the cerebrospinal fluid is called the area postrema.
- Walls of the 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 _____ is sometimes called the vomiting center.
- Area 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 _____ and _____ synapse on second order neurons in the nucleus gracilis and nucleus cuneatus in the lower medulla.
- Fasciculus gracilis
- Fasciculus cuneatus
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 _____; nuclei are _____; but myelinated tracts usually stain black with silver, iron, or osmium, and nuclei usually do not take these metallic stains.
- White matter
- Gray matter
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 _____ 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.
- Gracilis
- Cuneatus
The nucleus gracilis is on the dorsal surface of the _____ at the _____ level.
- Medulla
- Mid-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 _____ inside the olive.
- Gray matter
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 trigeminal tract
The central tegmental tract enters the _____ on its dorsal (posterior) surface.
- Inferior olivary nucleus
The spino-olivary tract enters the _____ on its convex lateral side.
- Inferior olivary nucleus
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 _____ tract, the posterior spinocerebellar tract, and the cuneocerebellar tract.
- Olivocerebellar
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 nucleus
- Central tegmental
The medullary reticular formation contains neurons whose axons form the _____.
- Lateral reticulospinal tract
The most easily assigned function of the _____ is the stimulation of the lower motor neurons for the _____ of the _____ during absent-minded walking.
- Medullary reticular formation
- 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 _____ gets its name from the Latin word for net: reticulum.
- Reticular formation
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 (anterior)
The inferior olivary nucleus projects to the _____ side of the cerebellum via the _____.
- 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
