The brainstem consists of the midbrain, pons, and medulla oblongata. It regulates vital functions like breathing, heart rate, and blood pressure. The medulla is the narrowest part and connects to the spinal cord. The pons lies above the medulla and contains fiber tracts and cranial nerve nuclei. The midbrain is the widest part and contains visual and auditory centers. Together these structures control basic body functions and relay information between the brain and spinal cord.

1. BRAIN STEM

2. Definition

3. PARTS
•brainstem (brain stem) is the distal part of
the brain that is made up of the
•midbrain,
•pons, and
•medulla oblongata.

4. Functions of brain stem
•they help to regulate breathing, heart rate,
blood pressure, and several other important
functions.
•brainstem houses cranial nerve nuclei and is a
passageway for many important neural pathways.

5. • There are three parts of the brainstem:
• the medulla oblongata is the narrowest and most distal part
• the pons lies anteriorly and in the middle segment of the brainstem
• and the midbrain is the widest and most superior segment.

6. MIDBRAIN

7. MID BRAIN

8. Anterior surface

9. Posterior surface

11. Structureof midbrain

12. Tectum and tegmentum

14. Features at superior colliculi level

16. At superior collicular level

18. Features at the level of inferior colliculus
transverse section

21. Blood supply

23. PONS

24. PONS

25. ANTERIOR SURFACE OF PONS/ventral surface

27. POSTERIOR SURFACE OF PONS/Dorsal surface

29. Structureof pons

30. BASILAR PART
• Basilar part consists of the longitudinal bundles of fibres, the
transverse fibres and the pontine nuclei:
• Longitudinal bundles of fibres contain corticopontine, corticonuclear
and corticospinal fibres.
• The corticopontine fibres relay in the ipsilateral pontine nuclei.
• The corticonuclear fibres terminate in the contralateral (and to some
degree ipsilateral) motor nuclei of the cranial nerves.

31. TEGMENTAL PART
• Tegmental part is traversed by a number of ascending and descending
tracts and includes a decussation of transversely running fibres, the
trapezoid body.
• also includes the nuclei of trigeminal (5th), abducent (6th), facial (7th)
and vestibulocochlear (8th) nerves

32. Transverse sectionthrough upperpart
features:

34. Transverse sectionof pons through lower part
Features:

36. BLOOD SUPPLY

37. MEDULLA OBLONGATA

38. Medulla oblongata

40. ANTERIOR SURFACE OF MEDULLA/VENTRAL
SURFACE

41. Cranial nerves arises from anterior surface

42. Cranial nerves arises from anterior surface

43. Posterior surface of medulla

44. Cond.......

45. Blood supply
•Anterior spinal
•Posterior spinal,
•Posterior inferiorcerebellar,
•Anterior inferior cerebellar,
•and vertebral arteries.

47. Applied anatomy

59. Hydrocephalus:excess accumulation of CSF.

64. SPINAL CORD

67. Structureof spinal cord

68. Cond....

74. Cauda equina

75. Filum terminale