Chapter 9 : Brainstem (2) Flashcards
1. Which one of the following nuclei does not project to the cerebellum? (A) Lateral reticular nucleus (B) Arcuate nucleus (C) Inferior olivary nucleus (D) Accessory (lateral) cuneate nucleus (E) Nucleus ambiguous
l-E. The nucleus ambiguus is a SVE cell column that gives rise to the motor components of
CN IX, CN X, and CN XI. The nucleus ambiguus also contains GVE (parasympathetic) neurons
with axons that innervate the heart via the vagal nerve.
2. Decussation of the superior cerebellar peduncles occurs in which area of the brain? (A) Rostral midbrain (B) Caudal midbrain (C) Rostral pons (D) Caudal pons (E) Cerebellum
2-B. Decussation of the superior cerebellar peduncles occurs in the caudal midbrain tegmentum at the level of the inferior colliculus.
3. The cerebral aqueduct is found in which part of the brain? (A) Telencephalon (B) Diencephalon (C) Mesencephalon (D) Metencephalon (E) Myelencephalon
3-C. The cerebral aqueduct is found in the mesencephalon; it connects the third ventricle to
the fourth ventricle.
- The base of the pons contains all of the following nuclei and fibers EXCEPT the
(A) cerebellar relay nuclei
(B) arcuate nuclei
(C) corticospinal fibers
(D) corticobulbar fibers
(E) exiting fibers of the abducent nucleus
4-B. The base of the pons contains corticospinal, corticobulbar, and corticopontine fibers and pontine nuclei (cerebellar relay nuclei). Exiting intra-axial abducent fibers of CN VI pass through thecortico spinal fibers in the base of the pons. Arcuate nuclei are displaced pontine nuclei found in the pyramids.
- All of the following statements concerning the trapezoid body are correct EXCEPT
(A) it is found in the ventral pontine tegmentum
(B) it contains the medial longitudinal fasciculus (MLF)
(C) it contains the medial lemniscus
(D) it contains aberrant corticobulbar fibers
(E) it contains auditory fibers
5-B. The trapezoid body contains auditory fibers from the cochlear and superior olivary nuclei, the medial lemniscus, and corticobulbar fibers. Exiting intra-axial abducent fibers pass through the trapezoid body. The medial longitudinal fasciculus (MLF) lies dorsal to this structure
- All of the following statements concerning the spinal trigeminal nucleus are correct EXCEPT
(A) it is a homolog of the substantia gelatinosa
(B) it gives rise to the dorsal trigeminothalamic tract
(C) it receives input from free nerve endings
(D) it projects to the contralateral ventral posteromedial nucleus of the thalamus
(E) it is found in the lateral pontine tegmentum
6-B. The spinal trigeminal nucleus of CN V extends from C3 to the caudal pole of the principal
sensory nucleus of the trigeminal nerve. It is considered a homolog of the substantia gelatinosa.
It lies in the lateral medulla and lateral pontine tegmentum and gives rise to the crossed ventral trigeminothalamic tract. The dorsal trigemino thalamic tract arises from the principal sensory nucleus of CN V.
- All of the following statements concerning the medulla oblongata are correct EXCEPT
(A) it extends from the pyramidal decussation to the inferior pontine sulcus
(B) it contains the facial nucleus
(C) it contains the medial and inferior vestibular nuclei
(D) it contains the inferior olivary nucleus
(E) it contains the nucleus ambiguous
7-B. On its ventral aspect, the medulla extends from the pyramidal decussation to the inferior pontine sulcus (pontobulbar sulcus); on its dorsal aspect, it extends from the pyramidal decussation to the striae medullares of the rhomboid fossa. The medial and inferior vestibular nuclei are found in the medulla and extend into the caudal pontine tegmentum. The inferior olivary nucleus, a cerebellar relay nucleus, is the most prominent nucleus of the medulla. The nucleus ambiguus is found in the medulla; it gives rise to SVE fibers of CN IX, CN X, and CN XI. The facial nucleus is found in the caudal pontine tegmentum.
- All of the following statements concerning the hypoglossal nucleus are correct EXCEPT
(A) it gives rise to SVE fibers
(B) it has axons that exit the medulla between the olive and the pyramid
(C) it lies dorsal to the medial longitudinal fasciculus (MLF)
(D) it innervates the intrinsic musculature of the tongue
(E) its intra-axial root fibers lie adjacent to the medial lemniscus
8-A. The hypoglossal nucleus of CN XII gives rise to GSE fibers. The hypoglossal nucleus lies
dorsal to the medial longitudinal fasciculus (MLF), gives rise to fibers that exit the medulla in the preolivary sulcus, and innervates the intrinsic and extrinsic muscles of the tongue (except the palatoglossus muscle, which is innervated by CN X). Intra-axial root fibers lie between the medial lemniscus and the inferior olivary nucleus.
- All of the following statements concerning the abducent nucleus are correct EXCEPT
(A) it is found in the pontine tegmentum
(B) it underlies the facial colliculus
(C) it exits the brainstem at the superior pontine sulcus
(D) it gives rise to fibers that traverse the cavernous sinus
(E) it gives rise to fibers that traverse the corticospinal tracts
9-C. The abducent nucleus of CN VI underlies the facial colliculus in the caudal pontine tegmentum. It gives rise to GSE fibers that innervate the lateral rectus muscle. It exits the brainstem at the inferior pontine sulcus (pontobulbar sulcus). Exiting abducent fibers pass through the corticospinal tracts, which traverse the base of the pons.
- All of the following statements concerning the motor nucleus of the trigeminal nerve are correct EXCEPT
(A) it plays a role in the corneal reflex
(B) it lies medial to the principal sensory nucleus of CN V
(C) it is located in the rostral pontine tegmentum
(D) it receives bilateral input from corticobulbar fibers
(E) it gives rise to SVE fibers
10-A. The motor nucleus of the trigeminal nerve (CN V) is a component of the SVE cell column,
lies medial to the principal sensory nucleus of CN V, is found in the rostral pontine tegmentum, and receives bilateral corticobulbar input. The afferent limb of the corneal reflex is the ophthalmic nerve (CN V-l); the efferent limb is the facial nerve (CN VII), which innervates the orbicularis oculi muscle.
- All of the following statements concerning the trochlear nerve are correct EXCEPT
(A) it has its nucleus in the midbrain tegmentum
(B) it exits the brainstem caudal to the inferior colliculus
(C) it decussates in the superior medullary velum
(D) it innervates a muscle that depresses the globe
(E) it innervates a muscle that extorts the globe
11-E. The trochlear nerve (CN IV) has its nucleus in the midbrain tegmentum at the level of the inferior colliculus. It decussates in the superior medullary velum and exits the brainstem lateral to the frenulum of the superior medullary velum. It is the only cranial nerve to exit the brainstem from the dorsal surface. It innervates the superior oblique muscle, which depresses, intorts, and abducts the eyeball.
- All of the following statements concerning the locus ceruleus are correct EXCEPT
(A) its neurons contain melanin
(B) its neurons contain dopamine
(C) it is located in the pons and midbrain
(D) it projects to the spinal cord
(E) it projects to the cerebral cortex
12-B. The locus ceruleus is a pigmented (melanin-containing) nucleus found in the rostral pontine tegmentum that extends into the midbrain. Its cells contain catecholamines (noradrenaline). It projects to all parts of the central nervous system (CNS), including the cerebral cortex and the spinal cord. Dopamine is found in the substantia nigra of the midbrain.
- All of the following statements concerning the oculomotor nuclear complex are correct
EXCEPT
(A) stimulation of its parasympathetic component results in mydriasis
(B) damage to its GSE fibers results in severe ptosis
(C) it is found in the midbrain at the level of the superior colliculus
(D) its preganglionic parasympathetic fibers synapse in the ciliary ganglion
(E) its exiting GSE fibers pass through the crus cerebri
13-A. Stimulation of the parasympathetic component results in miosis (sphincter pupillae
muscle). Preganglionic parasympathetic fibers synapse in the ciliary ganglion. The oculomotor
nuclear complex is found in the midbrain at the level of the red nucleus and the superior colliculus.
Exiting oculomotor fibers pass through the crus cerebri. Transection of these fibers results in severe ptosis, a dilated pupil, paralysis of the medial, superior, and inferior recti muscles and paralysis of the inferior oblique and the levator palpebrae muscles. The paralytic eye “looks down and out.”
Match the following structures to the appropriate brainstem division.
(A) Midbrain, at level of superior colliculus
(B) Midbrain, at level of inferior colliculus
(C) Tegmentum of pons
(D) Base of pons
(E) Lateral medulla
(F) Medial medulla
- Decussation of the superior cerebellar peduncle
14-B. The decussation of the superior cerebellar peduncle is diagnostic of midbrain division, at the level of the inferior colliculus.
Match the following structures to the appropriate brainstem division.
(A) Midbrain, at level of superior colliculus
(B) Midbrain, at level of inferior colliculus
(C) Tegmentum of pons
(D) Base of pons
(E) Lateral medulla
(F) Medial medulla
- Inferior olivary nucleus
15-E. The inferior olivary nucleus, a cerebellar relay nucleus, is the most prominent nucleus
in the lateral medulla.
