MEDULLA Flashcards
Floor of the 4th vent
Posterior Median Fissure, Hypoglossal Trigone, Vagal Trigone
This fissure is a continuation of the posterior median sulcus of the spinal cord.
Posterior Median Fissure
protuberance of the nucleus of the hypoglossal nerve (cranial nerve XII) into the floor of the fourth ventricle.
Hypoglossal Trigone
protuberance of the dorsal motor nucleus of the vagus nerve (cranial nerve X) into the floor of the fourth ventricle.
vagal trigone
This is the surface landmark of the arcuatocerebellar bundle of fibers running from the arcuate nucleus of the medulla oblongata to the cerebellum.
stria medullaris
roof of the fourth ventricle structures
anterior medullary velum, the cerebellum, and the tela choroidea
The lateral boundaries of the fourth ventricle
Brachium Conjunctivum, Retiform Body, Clava and Cuneate Tubercles
Medulla at level of pyramidal decussation
The fibers of the lower extremities are more lateral than are those of the upper extremities
fractures of the ________ or mass lesions in that location result in paralysis of the muscles of the upper extremities but may spare the muscles of the lower extremities.
odontoid
can result from a lesion in the lower medulla that injures the crossed fibers to the arm as well as the uncrossed fibers to the leg
paralysis of an ipsilateral arm and a contralateral leg (hemiplegia cruciata)
dorsal column nuclei are divided into two distinct areas which are
core and reticular zone
SPINAL TRIGEMINAL NUCLEUS of the medulla is continuous with the _____of the SC
substantia gelatinosa
it mediates dental pain
nucleus interpolaris
mediates tactile sensations from the oral mucosa.
nucleus oralis
Trigeminothalamic tract lamellation
fibers from the ophthalmic branch (V1) of the trigeminal nerve are located most lateral and those from the mandibular branch (V3) are most medial.
loss of kinesthesia and discriminative touch contralateral to the side of the lesion in the medulla. Where is the lesion?
medial lemniscus
inputs to cuneate nucleus
glossopharyngeal (cranial nerve IX) and vagus (cranial nerve X) nerves as well as from the vasopressor and cardioacceleratory areas of the posterior hypothalamus
______ triggers the accessory cuneate nucleus, via cardiovascular reflexes, to produce bradycardia and hypotension.
HPN
The inferior olivary nuclear complex consists of ______
Principal olive (the largest of the complex)
Dorsal accessory olive
Medial accessory olive
formed of astroblast-like cells, arterioles, sinusoids, and some apolar or unipolar neurons. It is one of several central nervous system areas that lack a blood-brain barrier.
area postrema
inferior olivary nuclear complex consists of three nuclear groups namely
Principal olive (the largest of the complex)
Dorsal accessory olive
Medial accessory olive
Afferent inputs to inferior olive
- Cerebral cortex via the corticospinal tract
- Basal ganglia via the central segmental tract
- Mesencephalon from the periaqueductal gray matter of the midbrain and the red nucleus via the central segmental tract
medulla oblongata, the dorsal column nuclei project to the contralateral accessory olive - cerebellum via the superior cerebellar peduncle the spinal cord, to the accessory olives of both sides via the spino-olivary tract.
major output of the inferior olivary complex is to the cerebellum
olivocerebellar tract
They pass through the hilum of the olive, traverse the medial lemniscus, and course through the opposite olive to enter the restiform body on their way to the cerebellum.
olivocerebellar tract
Accessory Nerve origins
spinal: from the accessory nucleus
cranial: from the caudal pole of the nucleus ambiguus in the medulla oblongata.
impaired function of the trapezius muscle
Downward and outward rotation of the scapula ipsilateral to the lesion
Moderate sagging of the ipsilateral shoulder
impaired function of the sternocleidomastoid muscle.
Weakness on turning the head to the side opposite the lesion
emergence of axons from dorsal motor nucleus of vagus
lateral surface of the medulla between the inferior olive and the inferior cerebellar peduncle
results in nausea, vomiting, and a change in heart rate because of connections with this area
connection of the vagus with vestibular nuclei
s a column of cells situated about halfway between the inferior olive and the nucleus of the spinal tract of the trigeminal nerve
nucleus ambiguous
emergence of axons of nucleus ambiguus
the lateral surface of the medulla between the inferior olive and the inferior cerebellar peduncle.
Afferents of nucleus ambiguus
Nucleus of the spinal tract of the trigeminal nerve.
Nucleus solitarius
nucleus receives general somatic afferent fibers from the external ear, external auditory canal, and external surface of the tympanic membrane.
Nucleus of the spinal tract of the trigeminal nerve.
These fibers convey general visceral sensations from the pharynx, larynx, trachea, and esophagus as well as the thoracic and abdominal viscera.
GVA of Nucleus solitarius
These fibers convey taste sensations from the region of the epiglottis.
SVA of Nucleus solitarius
efferent components of the glossopharyngeal
NUCLEUS AMBIGUUS
INFERIOR SALIVATORY NUCLEUS
hey are preganglionic general visceral efferent fibers that convey secretomotor impulses to the parotid gland. They travel via the lesser petrosal nerve to the otic ganglion, from which postganglionic fibers supply the parotid gland
INFERIOR SALIVATORY NUCLEUS
afferent components of the glossopharyngeal nerve
Nucleus of the spinal tract of the trigeminal nerve.
Nucleus solitarius.
This branch innervates the carotid body and carotid sinus, which are chemoreceptor and baroreceptor centers.
carotid sinus nerve
The two vestibular nuclei that appear at rostral levels of the medulla
inferior vestibular nucleus and the medial vestibular nucleus
zones of nucleus solitarius
caudal and medial: general visceral sensation and primarily cardio-respiratory function
rostral and lateral zone is concerned with special visceral (taste) function
gustatory (taste) zone receives taste sensations via three cranial nerves:
7, 9, 10
output of the gustatory zone
posterior thalamus (ventral posterior medial nucleus), which in turn projects to the primary gustatory cortex.
Lesions in the nucleus or tractus solitarius and their connections with the area postrema result in
early satiety and poor appetite
genesis of neurogenic pulmonary edema.
caudal zone of the nucleus solitarius, along with the dorsal motor nucleus of the vagus and the medial reticular formation,
brain stem nuclei involved in cardiovascular control
nucleus solitarius, along with the dorsal motor nucleus of the vagus, the caudal, and the rostral ventrolateral medulla
Lesions in the _______ have been shown to result in arterial blood pressure elevation
tractus solitarius
Lack of activity in _____________ neurons has been associated with development of hypertension.
caudal ventrolateral medulla
The _____________is critical for the tonic and reflexic regulation of blood pressure.
rostral ventrolateral medulla
____________contains primary inspiratory
neurons that project to the nucleus ambiguus and to spinal cord neurons that supply the diaphragm
DRG of nucleus solitarius
The ventral respiratory group in the nucleus ambiguus and nucleus retroambiguus contains____________
inspiratory and expiratory neurons.
Structures implicated in apnea in humans include
the nucleus solitarius, the nucleus ambiguus, the nucleus retroambiguus, the dorsal motor nucleus of the vagus, the region of the medial lemniscus, the region of the spinothalamic tract, and the medullary reticular formation, all bilaterally
where is the lesion for NPE
caudal brain stem, nucleus solitarius, the dorsal motor nucleus of the vagus, and the medial medullary reticular formation.
The __________ is in the medulla oblongata at the ventromedial margin of the descending tract and nucleus (spinal nucleus) of the trigeminal nerve and includes the adjacent reticular formation and nucleus solitarius.
sneezing center
phases of sneezing
nasal and respiratory
The afferent limb of the nasal phase consists of the _____________.
The efferent limb consists of ________________
ethmoidal (cranial nerve V) and olfactory (cranial nerve I) nerves, which project to the sneezing center in the medulla oblongata;
preganglionic fibers to the greater petrosal nerve (cranial nerve VII) and the sphenopalatine ganglion (cranial nerve VII),
Manifestations of respiratory phase of sneezing
ye closure, deep inspiration, pharyngeal closure, forceful expiration, dilation of the glottis, explosive air release through the mouth and nose, and expulsion of mucus and irritants.
phases of swallowing
oral, pharyngolaryngeal, and esophageal.
two regions in the medulla are involved in swallowing
The dorsal swallowing group (DSG) and VSG
contains the generator neurons which trigger, shape, and time the sequential or rhythmic swallowing pattern
DSG located within the nucleus solitarius and the adjacent reticular formation
contains the switching neurons, which distribute the swallowing drive to the various motor neuronal pools involved in swallowing.
VSG
Descending pathways that modify swallowing arise from _______
the prefrontal cortex, the limbic system, the hypothalamus, the midbrain, and the pons
__________ of the hypothalamus mediate the expression of yawning via connections to the hippocampus, pons, and medulla oblongata.
Oxytocinergic neurons in the paraventricular nucleus
yawn-producing hormones
dopamine, excitatory amino acids, and oxytoci
Blood supply of medulla
Vertebral
Anterior spinal
Posterior spinal
Posterior inferior cerebellar artery (PICA)
four vascular territories of the medulla
paramedian, olivary, lateral, and dorsal
paramedian territory receives its blood supply from the __________
vertebral and/or anterior spinal arteries
olivary territory receives an inconstant blood supply from the ________
vertebral artery.
e lateral territory receives a constant blood supply from Z________
the vertebral artery and a variable supply from the posterior inferior cerebellar artery.
The dorsal territory is supplied rostrally by the __________
posterior inferior cerebellar artery and caudally by the posterior spinal artery.