Medulla Oblongata Flashcards

Examine the medulla oblongata, its external landmarks, cranial nerve nuclei, ascending and descending pathways, blood supply, and vital functions.

Card 1 of 30Question

What is the medulla oblongata?

The inferior division of the brainstem, connecting the pons to the spinal cord.

In This Section

1. What is the medulla oblongata?

The inferior division of the brainstem, connecting the pons to the spinal cord.

2. What forms the superior boundary of the medulla oblongata?

The pontomedullary junction.

3. At which anatomical level does the medulla become continuous with the spinal cord?

Near the foramen magnum, approximately at the pyramidal decussation.

4. What are the medullary pyramids?

Paired longitudinal elevations on the anterior medulla containing descending corticospinal fibers.

5. What is the pyramidal decussation?

The crossing of most corticospinal fibers in the caudal medulla to form the lateral corticospinal tracts.

6. What structures form the prominent olives on the ventrolateral medulla?

The underlying inferior olivary nuclei.

7. What is the principal function of the inferior olivary nucleus?

Providing climbing fiber input to the contralateral cerebellum for motor learning and coordination.

8. Which cranial nerve emerges from the preolivary sulcus?

The hypoglossal nerve (cranial nerve XII).

9. Which cranial nerves emerge from the postolivary sulcus?

The glossopharyngeal (IX), vagus (X), and cranial accessory rootlets traditionally assigned to XI.

10. Which two elevations appear on the posterior surface of the closed medulla?

The gracile and cuneate tubercles.

11. Which nuclei lie beneath the gracile and cuneate tubercles?

The gracile and cuneate nuclei, which relay discriminative touch, vibration, and conscious proprioception.

12. What is the sensory decussation of the medulla?

The crossing of internal arcuate fibers from the gracile and cuneate nuclei.

13. Which ascending tract forms after the internal arcuate fibers cross?

The medial lemniscus.

14. Which part of the fourth ventricle is formed by the posterior surface of the open medulla?

The inferior portion of the floor of the fourth ventricle.

15. What is the obex?

The inferior tip of the fourth ventricle, near its transition into the central canal.

16. Which cerebellar peduncle primarily connects the medulla to the cerebellum?

The inferior cerebellar peduncle.

17. What is the principal function of the hypoglossal nucleus?

Providing somatic motor innervation to the intrinsic and most extrinsic tongue muscles.

18. Which medullary nucleus provides branchial motor fibers to muscles involved in swallowing and phonation?

The nucleus ambiguus.

19. What is the function of the dorsal motor nucleus of the vagus?

Providing preganglionic parasympathetic fibers to thoracic and abdominal viscera.

20. Which medullary nucleus receives taste and visceral sensory information?

The nucleus of the solitary tract.

21. Which medullary nucleus processes pain and temperature sensation from the face?

The spinal trigeminal nucleus, especially its caudal portion.

22. Which medullary nuclei contribute to hearing and balance?

The cochlear and vestibular nuclei near the pontomedullary junction.

23. Which medullary neuronal group is essential for generating the respiratory rhythm?

The pre-Botzinger complex in the ventrolateral medulla.

24. Which medullary region contributes to sympathetic cardiovascular regulation?

The rostral ventrolateral medulla.

25. Which cranial nerves carry the main afferent signals from arterial baroreceptors to the medulla?

The glossopharyngeal nerve (IX) and vagus nerve (X).

26. Which arteries provide the principal blood supply to the medulla oblongata?

Branches of the vertebral arteries, anterior spinal artery, and posterior inferior cerebellar arteries.

27. Which artery commonly supplies the medial medulla?

The anterior spinal artery, with contributions from vertebral artery branches.

28. What is lateral medullary syndrome also called?

Wallenberg syndrome.

29. Which vascular occlusions commonly cause lateral medullary syndrome?

Occlusion of the vertebral artery or posterior inferior cerebellar artery.

30. What is a characteristic neurological finding in medial medullary syndrome?

Contralateral limb weakness with possible ipsilateral tongue weakness.