Untitled Quiz

Medulla Oblongata

• The medulla oblongata is the most inferior part of the brainstem.
• It resembles an upward widening of the spinal cord.
• It's involved in vital autonomic functions such as regulating heart rate, breathing, and blood pressure.
• It contains crucial nuclei controlling various cranial nerves.

Anterior Surface Features

• The anterior surface of the medulla oblongata has a prominent anterior median fissure.
• The pyramids are prominent structures on the anterior surface.
• The pyramidal decussation is where the corticospinal tracts cross over to the opposite side.
• An olivary complex is visible on the anterior surface.
• Several cranial nerves exit the medulla from the anterior surface.
• Regions include the retroolivary sulcus.

Posterior Surface Features

• The posterior surface of the medulla oblongata is part of the floor of the fourth ventricle.
• It includes important structures such as the inferior cerebellar peduncles.
• Cranial nerve exit points are found on this surface, including the glossopharyngeal, vagus, and accessory nerves.

Inferior Cerebellar Peduncle

• The inferior cerebellar peduncle connects the medulla to the cerebellum.
• It contains various fiber tracts, including the posterior spinocerebellar tract, some fibers of the anterior spinocerebellar tract, cuneocerebellar tract, and olivocerebellar tract.
• It connects the cerebellum to parts of the brainstem and spinal cord related to movement.

4th Ventricle and Rhomboid Fossa

• The medulla oblongata forms part of the floor of the fourth ventricle and the surrounding rhomboid fossa.
• The rhomboid fossa has a quadrangular shape with a lower triangle area related to the medulla oblongata.
• The upper triangle connects to the pons and the ventricle.

Cranial Nerves

• The medulla oblongata gives rise to several cranial nerves.
• These include the glossopharyngeal, vagus, accessory, and hypoglossal nerves.
• The nuclei of these cranial nerves are located within the medulla.

Spinal Tract & Nuclei of Trigeminal Nerve

• The trigeminal nerve's spinal tract and nuclei are located in the medulla, within a posterolateral position, associated with sensations of pain and temperature from the head and neck.
• The medulla is located in pons, medulla, and upper spinal cord segments 1-2.

Solitary Nucleus

• The solitary nucleus is related to taste sensation.
• The facial and glossopharyngeal cranial nerves connect to this nucleus.

Dorsal Nucleus of Vagus Nerve

• The dorsal nucleus of the vagus nerve is a parasympathetic nucleus associated with the vagus nerve.

Inferior Salivatory Nucleus

• The inferior salivatory nucleus is a parasympathetic nucleus involved in the production of saliva.
• Cranial nerve IX (glossopharyngeal) has connections to this nucleus.

Vestibular Nuclei

• Four vestibular nuclei are located in the medulla oblongata (superior, inferior, medial, lateral).
• These nuclei receive input from the inner ear.
• They are associated with balance and equilibrium, essential for sensing position and motion.

Reticular Nuclei at Medulla Level

• Several reticular nuclei are located in the medulla.
• They include the reticularis lateralis, ventralis, gigantocellularis, parvocellularis, and paramedianus nuclei.
• They mediate numerous functions, including automatic activities associated with consciousness.

Internal Structure of Medulla Oblongata (Transverse Section)

• Pyramidal decussation, where the corticospinal tracts cross
• Fasciculus gracilis and cuneatus, posterior column–medial lemniscus tract.
• Other tracts, including sensory and motor pathways.

Transverse Section of Medulla (at specific levels)

• Sections at various locations show unique features. Levels like the inferior olive, pyramidal decussation, and upper medulla levels have distinctive organizational patterns of nerves and tracts.

Additional information

• The medulla controls vital functions (e.g., heart rate, breathing, blood pressure) important for survival.
• Trigeminal nerve branches innervate the face.