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Questions and Answers
The medulla oblongata extends from the pons to the spinal cord.
The medulla oblongata extends from the pons to the spinal cord.
True (A)
The facial nerve (VII) emerges between the pons and the anterior median fissure.
The facial nerve (VII) emerges between the pons and the anterior median fissure.
False (B)
The hypoglossal trigone is located lateral to the vagal trigone on the floor of the fourth ventricle.
The hypoglossal trigone is located lateral to the vagal trigone on the floor of the fourth ventricle.
False (B)
The inferior cerebellar peduncle connects the medulla oblongata to the cerebellum.
The inferior cerebellar peduncle connects the medulla oblongata to the cerebellum.
The pyramids of the medulla contain corticothalamic fibers.
The pyramids of the medulla contain corticothalamic fibers.
The vallecula of the cerebrum embraces the medulla oblongata dorsally.
The vallecula of the cerebrum embraces the medulla oblongata dorsally.
The 'open part' of the medulla contains the upward continuation of the central canal of the spinal cord.
The 'open part' of the medulla contains the upward continuation of the central canal of the spinal cord.
The trigeminal tubercle is always a well-defined elevation on the dorsal surface of the closed part of the medulla.
The trigeminal tubercle is always a well-defined elevation on the dorsal surface of the closed part of the medulla.
The abducens nerve (VI) emerges between the pons and the olive.
The abducens nerve (VI) emerges between the pons and the olive.
The gracile and cuneate tubercles are located dorsally in the lower medulla.
The gracile and cuneate tubercles are located dorsally in the lower medulla.
The rootlets of the ninth, tenth and cranial part of the eleventh nerves emerge lateral to the olive.
The rootlets of the ninth, tenth and cranial part of the eleventh nerves emerge lateral to the olive.
The hypoglossal nucleus is located under the dorsal trigone.
The hypoglossal nucleus is located under the dorsal trigone.
The dorsal nucleus of the vagus contains motor cell bodies for skeletal muscle.
The dorsal nucleus of the vagus contains motor cell bodies for skeletal muscle.
The cells of the nucleus of the tractus solitarius are the most loosely packed of any brainstem nucleus.
The cells of the nucleus of the tractus solitarius are the most loosely packed of any brainstem nucleus.
The nucleus ambiguus contains motor cell bodies for muscles of the larynx, soft palate, pharynx, and upper esophagus, all distributed by branches of the vagus nerve, aside from the supply to stylopharyngeus, which is innervated by the facial nerve.
The nucleus ambiguus contains motor cell bodies for muscles of the larynx, soft palate, pharynx, and upper esophagus, all distributed by branches of the vagus nerve, aside from the supply to stylopharyngeus, which is innervated by the facial nerve.
The spinal nucleus and tract of the trigeminal nerve lie medial to the nucleus of the tractus solitarius.
The spinal nucleus and tract of the trigeminal nerve lie medial to the nucleus of the tractus solitarius.
The inferior olivary nucleus fibers (olivocerebellar) decussate across the midline to enter the superior cerebellar peduncle.
The inferior olivary nucleus fibers (olivocerebellar) decussate across the midline to enter the superior cerebellar peduncle.
The gracile and cuneate nuclei give origin to the spinal lemniscus.
The gracile and cuneate nuclei give origin to the spinal lemniscus.
The accessory cuneate nucleus conveys proprioceptive impulses from the upper limb to the cerebellum via the superior peduncle.
The accessory cuneate nucleus conveys proprioceptive impulses from the upper limb to the cerebellum via the superior peduncle.
The medullary reticular formation is located primarily between the pyramids and the floor of the fourth ventricle.
The medullary reticular formation is located primarily between the pyramids and the floor of the fourth ventricle.
The cardiac, respiratory, and vasomotor centers are anatomically demonstrable as distinct nuclei within the reticular formation.
The cardiac, respiratory, and vasomotor centers are anatomically demonstrable as distinct nuclei within the reticular formation.
The area postrema, located near the gracile nuclei, is protected by the blood-brain barrier.
The area postrema, located near the gracile nuclei, is protected by the blood-brain barrier.
The brainstem reticular formation is only responsible for motor activity.
The brainstem reticular formation is only responsible for motor activity.
The reticulospinal tracts, originating from the reticular formation cells, are part of the pyramidal system.
The reticulospinal tracts, originating from the reticular formation cells, are part of the pyramidal system.
The medulla is supplied ventrally by branches of the vertebral and basilar arteries.
The medulla is supplied ventrally by branches of the vertebral and basilar arteries.
Damage to the anterior spinal artery results in paralysis of the tongue on the opposite side.
Damage to the anterior spinal artery results in paralysis of the tongue on the opposite side.
Dysphonia and dysphagia result from damage to the spinal lemniscus.
Dysphonia and dysphagia result from damage to the spinal lemniscus.
Damage to the vestibular nuclei results in anosmia.
Damage to the vestibular nuclei results in anosmia.
The medial medullary syndrome includes hemiplegia on the same side as the lesion.
The medial medullary syndrome includes hemiplegia on the same side as the lesion.
Reticular formation cells do not receive input from the hypothalamus.
Reticular formation cells do not receive input from the hypothalamus.
Flashcards
Medulla Oblongata
Medulla Oblongata
A structure in the brainstem that connects the pons and spinal cord.
Closed Part of Medulla
Closed Part of Medulla
The lower end of the medulla containing the central canal's continuation.
Open Part of Medulla
Open Part of Medulla
The upper end of the medulla where the central canal becomes visible and connects to the fourth ventricle.
Pyramid of Medulla
Pyramid of Medulla
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Olive in Medulla
Olive in Medulla
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Cranial Nerves
Cranial Nerves
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Hypoglossal Trigone
Hypoglossal Trigone
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Vagal Trigone
Vagal Trigone
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Gracile Tubercles
Gracile Tubercles
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Cuneate Tubercles
Cuneate Tubercles
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Vital Centres
Vital Centres
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Area Postrema
Area Postrema
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Reticular Formation
Reticular Formation
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Extrapyramidal System
Extrapyramidal System
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Circadian Rhythms
Circadian Rhythms
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Medullary Blood Supply
Medullary Blood Supply
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Medial Medullary Syndrome
Medial Medullary Syndrome
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Lateral Medullary Syndrome
Lateral Medullary Syndrome
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Horner's Syndrome
Horner's Syndrome
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Spinal Tracts
Spinal Tracts
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Decussation of the pyramids
Decussation of the pyramids
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Hyoglossal nucleus
Hyoglossal nucleus
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Dorsal nucleus of the vagus
Dorsal nucleus of the vagus
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Nucleus of the tractus solitarius
Nucleus of the tractus solitarius
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Inferior olivary nucleus
Inferior olivary nucleus
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Cuneate nucleus
Cuneate nucleus
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Gracile nucleus
Gracile nucleus
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Nucleus ambiguus
Nucleus ambiguus
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Study Notes
Medulla Oblongata: Structure and Function
- Located between the pons and spinal cord, positioned vertically from the occipital bone to the atlas, within the cerebellar vallecula.
- Divided into an 'open' part (upper end, fourth ventricle floor) and a 'closed' part (lower end, spinal cord canal continuation).
- Ventral aspect: midline grooves, prominent pyramids (corticospinal fibers), olives (inferior olivary nucleus), and inferior cerebellar peduncles.
- Cranial nerve attachments: nerves VI, VII (and its intermedius component), VIII, IX, X, and XI rootlets emerge from distinct locations relative to the pons, pyramids, olives and inferior cerebellar peduncles. Nerve XII rootlets arise from areas between the pyramid and olive.
- Dorsal aspect: lower fourth ventricle floor, gracile and cuneate tubercles, and trigeminal tubercle.
Internal Structure
- Upper medulla: easily identifiable pyramids and olives.
- Closed medulla: retains pyramids ventrally, but adds gracile and cuneate tubercles dorsally.
- Pyramids decussate (cross) in the lower medulla, followed by medial lemniscus fiber decussation slightly higher.
- Nuclei positioned below fourth ventricle floor: hypoglossal, dorsal vagus, nucleus of tractus solitarius, spinal trigeminal nucleus, vestibular and cochlear nuclei, nucleus ambiguus, and inferior olivary nucleus.
Nuclei and Their Functions
- Hypoglossal nucleus: controls hypoglossal nerve for tongue movements.
- Dorsal vagal nucleus: controls cardiac, visceral muscle and gland secretions (primarily stomach). Its sensory role is now attributed to nucleus of tractus solitarius.
- Nucleus of tractus solitarius: receives taste and visceral sensory fibers (e.g. from carotid sinus, carotid body, aortic arch). Crucial for cough, sneeze, gag, and vomiting reflexes.
- Nucleus ambiguus: controls skeletal muscles of the larynx, soft palate, pharynx, and upper esophagus (motor).
- Inferior olivary nucleus: C-shaped lamina; its fibers (olivocerebellar) decussate and enter the inferior cerebellar peduncle.
- Gracile and cuneate nuclei: receive spinal cord sensory fibers; responsible for medial lemniscus formation. Cuneate cells with accessory cuneate nucleus convey upper limb proprioceptive information to cerebellum.
- Medullary reticular formation: irregular cell and fiber mass interspersed with other structures. Includes cardiovascular (cardiac, respiratory, vasomotor), cough, sneeze, gag, vomit centers. Vital for alertness and consciousness; major role in controlling motor activity (extrapyramidal), sensory input modulation (thalamus), autonomic function, and circadian rhythms.
Blood Supply and Clinical Syndromes
- Ventral supply: vertebral and basilar arteries.
- Lateral and dorsal supply: posterior inferior cerebellar artery.
- Medial medullary syndrome: damage to vessels supplying the pyramid, medial lemniscus, and hypoglossal nucleus results in tongue paralysis, contralateral hemiplegia, and sensory loss.
- Lateral medullary syndrome (syndrome of the posterior inferior cerebellar artery): damage produces vocal fold paralysis, dysphagia, facial and body sensory loss, Horner's syndrome, vertigo, nystagmus, and nausea/vomiting,
Additional Structures
- Area postrema: near gracile nuclei. Contains vomiting center and chemoreceptor trigger zone. Lacks blood-brain barrier.
- Medullary veins: drain dorsally to occipital sinuses, and ventrally into basilar plexus and inferior petrosal sinuses.
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Description
Explore the intricate structure and functions of the medulla oblongata, located between the pons and the spinal cord. This quiz covers key anatomical features, cranial nerve attachments, and the medulla's internal structure, providing a deep understanding of its role in the nervous system.
