Chapter 27: Pons Flashcards
Pons is Latin for bridge, and the pons is the bridge between the midbrain and the _____.
- Medulla
The pons is also the bridge between the brainstem and the _____.
- Cerebellum
The ventral (or anterior) half of the _____ is full of pontine nuclei.
- Pons
Pontine nuclei, in the strict sense, are confined to the _____ half of the ___.
- Ventral
- Pons
The _____ share the ventral half, or base, of the pons with the axons of the corticospinal tracts.
- Pontine nuclei
The base of the pons contains the _____ and the myelinated fibers of the _____ tracts.
- Pontine nuclei
- Corticospinal
The retrotrapezoid nucleus, which detects CO2, lies between the base of the pons and the facial nucleus just superior (or rostral) to boundary between the _____ and the _____.
- Pons
- Medulla
The retrotrapezoid nucleus is just dorsal (or posterior) to the _____ of the _____ in the most caudal part of the _____.
- Base
- Pons
- Pons
The _____ is the body’s principal CO2 detector.
- Retrotrapezoid nucleus
The pontine nuclei in the _____ of the _____ receive input from the ipsilateral motor cortex of the cerebrum about its intentions.
- Base
- Pons
Axons from the motor cortex of the cerebrum synapse on neurons in the _____ pontine nuclei.
- Ipsilateral
Neurons in the pontine nuclei signal the intentions of the _____ of the _____ to neurons in the contralateral cerebellar cortex.
- Motor cortex
- Cerebrum
Axons of neurons in pontine nuclei synapse on neurons in the _____ cerebellar cortex.
- Contralateral
The left cerebellar cortex receives information about the intentions of the _____ cerebral cortex from neurons in the _____ side of the base of the pons.
- Right
- Right
The left cerebellar cortex then assists the _____ cerebral cortex in carrying out an action.
- Right
Axons from the pontine nuclei to the _____ side of the cerebellum make up the middle cerebellar peduncle.
- Contralateral
The right middle cerebellar peduncle consists of axons of neurons in the _____ pontine nuclei that synapse on neurons in the _____ cerebellar cortex.
- Left
- Right
Each _____ is made up of axons from neurons in the _____ side of the _____ of the pons.
- Middle
- Contralateral
- Base
The left side of the cerebellum projects to the _____ side of the forebrain through the left superior cerebellar peduncle.
- Right
Each side of the cerebellum projects to the contralateral side of the forebrain through the ipsilateral _____.
- Superior cerebellar peduncle
Because the cerebellum is dorsal (or posterior) to the fourth ventricle, the superior cerebellar peduncles leave the cerebellum _____ to the fourth ventricle.
- Dorsal
The superior cerebellar peduncles leave the _____ dorsal (or posterior) to the fourth ventricle and remain in the roof of the fourth ventricle until they reach the lower midbrain.
- Cerebellum
The left superior cerebellar peduncle reaches the _____ side of the forebrain by crossing under the cerebral aqueduct in the lower (or caudal) midbrain.
- Right
The superior cerebellar peduncles cross each other ventral to the _____ in the _____.
- Cerebral aqueduct
- Lower midbrain
The crossing (or decussation) of the superior cerebellar peduncles is a prominent feature of the _____.
- Lower midbrain
The superior cerebellar peduncles are in the lateral sides of the roof of the _____.
- Fourth ventricle
The ventral half of the pons is the _____; the dorsal half is the tegmentum.
- Base
The part of the pons between the base and the fourth ventricle is the _____.
- Tegmentum
The motor nucleus of the trigeminal nerve is in the dorsolateral corner of the _____ of the pons.
- Tegmentum
The _____ nucleus of the trigeminal is present only at the mid-pontine level.
- Motor
The spinal tract and nucleus of the trigeminal descend from the midpontine level in the lateral part of the _____ of the _____.
- Tegmentum
- Pons
The spinal tract and nucleus of the trigeminal are just ventral to the lateral vestibular nucleus in the _____ of the lower (or caudal) pons.
- Tegmentum
The mesencephalic nucleus of the trigeminal extends upward (or rostrad) from the mid pontine level in the lateral wall of the _____.
- Fourth ventricle
The mesencephalic tract of the trigeminal is ventral to the _____.
- Superior cerebellar peduncle.
The nucleus ceruleus is in the dorsal part of the _____ of the middle and upper pons ventral and medial to the mesencephalic tract of the trigeminal.
- Tegmentum
The nucleus ceruleus is an essential alertness center in the _____ of the middle and upper pons.
- Dorsal tegmentum
Neurons in the _____ project to many other brain centers to keep them awake.
- Nucleus ceruleus
Projections of the nucleus ceruleus release norepinephrine in several forebrain nuclei to increase _____.
- Alertness (wakefulness)
The _____ is the principal source of norepinephrine in the central nervous system.
- Nucleus ceruleus
The nucleus ceruleus is ventral and medial to the _____ tract of the _____.
- Mesencephalic
- Trigeminal
The medial lemniscus is a thick vertical ribbon of _____ matter in the medulla, but it becomes a thick horizontal ribbon of _____ matter in the pons.
- White
- White
The medial lemniscus is a thick _____ ribbon of white matter forming the ventral (or anterior) border of the tegmentum in the pons.
- Horizontal
The ventral trigeminothalamic tract is a thin ribbon of _____ on the dorsal side of the medial lemniscus.
- White matter
Since the ventral trigeminothalamic tract carries _____ information from the _____ side of the face from the _____ of the _____ to the thalamus, it cannot be present below the mid-pontine level.
- Epicritic
- Contralateral
- Principal sensory nucleus
- Trigeminal
The ventral trigeminothalamic tract which carries _____ information from the _____ side of the face is on the dorsal side of the _____ which carries _____ information from the _____ side of the body.
- Epicritic
- Contralateral
- Medial lemniscus
- Epicritic
- Contralateral
The ventral trigeminothalamic tract is ventral to the central tegmental tract and dorsal to the _____ in the middle and upper pontine levels.
- Medial lemniscus
The central tegmental tract, which carries information from the red nucleus to the _____, is dorsal to the _____ tract.
- Inferior olivary nucleus
- Ventral trigeminothalamic
The nucleus of the lateral lemniscus, a relay center for _____, is on the lateral side of the central tegmental tract at the mid-pontine level.
- Hearing
The lateral lemniscus, which carries auditory information from the _____ to the _____, is on the lateral side of the nucleus of the lateral lemniscus.
- Superior olivary nucleus
- Inferior colliculus
The lateral lemniscus is on the lateral side of the _____ of the _____.
- Nucleus
- Lateral lemniscus
The nucleus of the lateral lemniscus on the lateral side of the _____.
- Central tegmental tract
The central tegmental tract is _____ to the medial lemniscus.
- Dorsal
The lateral lemniscus is _____ to the medial lemniscus.
- Dorsolateral
The lateral lemniscus ascends from the superior olivary nucleus to the inferior colliculus through the lateral side of the _____ of the _____.
- Tegmentum
- Pons
The anterolateral system, formed by the merger of the _____, _____, and spinoreticular tract ascends through the pons between the lateral lemniscus and the middle cerebellar peduncle.
- Lateral spinothalamic tract
- Anterior spinothalamic tract
The anterolateral system is _____ to the lateral lemniscus in the pons.
- Lateral
The pontine reticular formation is a network of neurons and axons occupying most of the tegmentum of the _____.
- Pons
Some neurons in the pontine reticular formation have long axons that form the _____.
- Medial (pontine) reticulospinal tract
The axons in the medial reticulospinal tract synapse on internuncial neurons that control lower motor neurons for _____ of the _____.
- Extensors
- Lower extremity
Neurons in the pontine reticular formation project through only the _____ medial reticulospinal tract, but neurons in the medullary reticulospinal tract project through _____ reticulospinal tracts.
- Ipsilateral
- Both lateral
The nucleus raphe magnus is on the midline between the _____ and _____ reticular formations in the lower (or caudal) pons.
- Right
- Left
The nucleus raphe magnus gets its name from its _____ because a raphe is where two sides join.
- Location (position)
The nucleus raphe magnus is on the midline of the tegmentum of the lower pons between the right and left sides of the reticular formation.
- Tegmentum
- Reticular formation
Pain transmission in the spinal cord is inhibited by projections of the _____ through the raphespinal tract.
- Nucleus raphe magnus
Axons in the raphespinal tract release enkephalin in the posterior horn of the spinal cord to inhibit the transmission of _____.
- Pain
The release of _____ in the posterior horn of the spinal cord _____ the transmission of pain.
- Enkephalin
- Inhibits
Projections of the _____ through the _____ tract inhibit pain transmission in the posterior horn of the spinal cord by releasing _____.
- Nucleus raphe magnus
- Raphespinal
- Enkephalin
The rostral half of the _____ lies between the pons and the cerebellum.
- 4th ventricle
The corticospinal tract pass through the _____ of the pons.
- Base
Pontine nuclei surround the _____ in the base of the pons.
- Corticospinal tract
Pontine nuclei receive projections from the _____.
- Ipsilateral cerebral cortex
Pontine nuclei project to the _____ cortex through the _____.
- Contralateral cerebellar
- Middle cerebellar peduncle
Pontine projections to the cerebellar cortex are more important for _____ than for _____.
- Coordination
- Muscle tone
The facial nucleus in the tegmentum of the _____ pons contains _____ motor neurons for facial muscles.
- Caudal (lower)
- Lower
The retrotrapezoid nucleus superficial to the _____ monitors _____.
- Facial nucleus
- Carbon dioxide
The _____ nuclei which surround the superior cerebellar peduncles in the _____ pons regulate the timing of _____.
- Parabrachial
- Rostral (upper)
- Exhalation
The reticular formation in the _____ of the pons projects to internuncial neurons for _____ through the _____ tract.
- Tegmentum
- Extensors
- Ipsilateral medial reticulospinal tract
The _____ in the lateral periventricular gray of the pons is a critical wakefulness center.
- Nucleus ceruleus (locus ceruleus)