Ch. 24 Perceptions and Relays in the Medulla

Question 1

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

Answer 1

central canal

Question 2

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

Answer 2

4th ventricle

Question 3

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

Answer 3

cerebrospinal fluid

Question 4

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

Answer 4

walls

obex

Question 5

Neurons in the ________ _____________ detect toxins in the cerebrospinal fluid.

Answer 5

area postrema

Question 6

Neurons in the area postrema project to the preganglionic parasympathetic neurons in the _________ _________ __________ of the ________ __________ that control the muscles of the stomach

Answer 6

dorsal motor nucleus

vagus nerve

Question 7

When they detect toxins in the cerebrospinal fluid neurons in the area postrema initiate vomiting through their projections to the _________ _________ ___________ of the ________ __________.

Answer 7

dorsal motor nucleus

vagus nerve

Question 8

The area _____________ is sometimes called the vomiting center.

Answer 8

postrema

Question 9

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

Answer 9

protopathic

Question 10

Axons in the spinothalamic tracts synapse only in the _____________.

Answer 10

thalamus

Question 11

The axons in the fasciculus gracilis and fasciculus cuneatus synapse on ____ in the nucleus gracilis and nucleus cuneatus in the lower medulla

Answer 11

second order neurons

Question 12

Just as the fasciculus cuneatus is __________ to the fasciculus gracilis, the nucleus cuneatus is ___________ to the nucleus gracilis.

Answer 12

lateral

lateral

Question 13

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

Answer 13

secondary sensory

Question 14

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.

Answer 14

nucleus gracilis

Question 15

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

Answer 15

right medial lemniscus

Question 16

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

Answer 16

internal arcuate fibers

Question 17

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

Answer 17

medial lemniscus

Question 18

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

Answer 18

epicritic

right lower

Question 19

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.

Answer 19

secondary sensory

Question 20

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

Answer 20

nucleus gracilis

lower extremity

Question 21

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

Answer 21

nucleus cuneatus

upper extremity

Question 22

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

Answer 22

dorsal

Question 23

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

Answer 23

cross

midline

Question 24

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

Answer 24

dorsal

Question 25

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.

Answer 25

tracts: white nuclei: gray

Question 26

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.

Answer 26

decussation

Question 27

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 ______________.

Answer 27

decussation

Question 28

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.

Answer 28

middle medulla | gracilis

Question 29

The nucleus gracilis is on the dorsal surface of the ___________ at the mid-medulla level

Answer 29

medulla

Question 30

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

Answer 30

fasciculus cuneatus

Question 31

The medial lemniscus contacts the posterior surface of the _____________ throughout the medulla

Answer 31

pyramid

Question 32

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

Answer 32

lateral

Question 33

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

Answer 33

cuneatus

Question 34

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

Answer 34

posterior spinocerebellar

Question 35

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

Answer 35

olive

Question 36

The inferior olivary nucleus is wavy ribbon of _________ matter inside the olive

Answer 36

gray

Question 37

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.

Answer 37

spino-olivary tract

Question 38

The central tegmental tract carries messages from the _______ ___________ of the ____________ to the ipsilateral ____________ __________ __________ of the ___________.

Answer 38

red nucleus midbrain inferior olivary nucleus medulla.

Question 39

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

Answer 39

central tegmental tract

Question 40

The central tegmental tract enters the _____________ __________ ___________ on its dorsal (or posterior surface.

Answer 40

inferior olivary nucleus

Question 41

The spino-olivary tract enters the inferior olivary nucleus on its ____ side

Answer 41

convex lateral

Question 42

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

Answer 42

inferior olivary nucleus

Question 43

The central tegmental tract tells the _____________ _________ __________ what the action was intended to be .

Answer 43

inferior olivary nucleus

Question 44

The ___________ _________ __________ compares intention and action and communicates that comparison to the contralateral cerebellum.

Answer 44

inferior olivary nucleus

Question 45

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

Answer 45

cerebellum

Question 46

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 ___________ ______________ _________.

Answer 46

central tegmental tract

Question 47

The cerebellum to ______ __________ to _____________ ________ _________ to cerebellum circuit is responsible for the simpler aspects of motor learning

Answer 47

red nucleus | inferior olivary nucleus

Question 48

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

Answer 48

left left right.

Question 49

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 ____________ __________ __________.

Answer 49

red nucleus | inferior olivary nucleus

Question 50

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

Answer 50

cerebellum

Question 51

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

Answer 51

restiform body

Question 52

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

Answer 52

olivocerebellar tract

Question 53

The olivocerebellar tract curves dorsad to join the _____________ ____________________ _______ and cuneocelebellar tract to form the restiform body.

Answer 53

posterior spinocerebellar tract

Question 54

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.

Answer 54

inferior olivary | central tegmental tract

Question 55

The medullary reticular formation contains neurons whose axons form the __________ _____________________ _________.

Answer 55

lateral reticulospinal tract

Question 56

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.

Answer 56

flexion | lower extremity

Question 57

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

Answer 57

neurons

Question 58

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

Answer 58

reticular

Question 59

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

Answer 59

reticular

Question 60

The nucleus ambiguus is embedded in the ________________ ________________ ventromedial to the ___________ ___________________ nucleus.

Answer 60

reticular formation | spinal trigeminal

Question 61

The inferior olivary nucleus is _______________ to the reticular formation

Answer 61

ventral (or anterior)

Question 62

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

Answer 62

contralateral | restiform body

Question 63

The inferior olivary nucleus receives information from the _______ ____________ of the midbrain via the _____________ __________________ ____________.

Answer 63

red nucleus | central tegmental tract

Question 64

The red nucleus receives information from the __________________ side of the cerebellum via the _____________ ______________ ______________.

Answer 64

contralateral | superior cerebellar peduncle

Question 65

The medial lemniscus is ____________ to the inferior olivary nucleus

Answer 65

medial

Question 66

Each medial lemniscus carries _____________ information from the ___________________ side of the body to the ______________.

Answer 66

epicritic contralateral thalamus