The document describes the anatomy and features of the myelencephalon, which forms the medulla oblongata. It notes that the myelencephalon extends from the rhombencephalic isthmus to the cervical flexure. Key features include lateral walls that are everted compared to the spinal cord, and a roof plate covered by pia mater and vascular mesenchyme called the tela choroidea. The medulla contains three motor nuclei and receives sensory input from cranial nerves related to hearing, taste, and the head.

2. • 1.Metencephalon(from pontine flexure to
rhombencephalic isthmus)
• 2.Myelencephalon(R.I to cervical flexure)

3. • Forms medulla oblongata
• DIFFERENCE FROM SPINAL CORD:
• 1.lateral walls are everted
• 2.Roof plate:single layer of ependymal cells covered by
vascular mesenchyme called Pia Mater..Together these
constitute Tela Choroidea

4. • 3 motor nuclei
• Medial to Lateral
• Somatic efferent..Sp.visceral efferent..General Visceral
efferent

5. • Extent: up to mesencephalon…called som.efferent motor
column
• Hypoglossal nerve nucleus supplying muscles of tongue

6. • Extent: up to Metencephalon
• CN IX,X,XI

7. • Muscles of
• GIT
• Respiratory tract

8. • Med to lateral
• Som.aff
• Sp.visceral aff
• Gen.visceral aff

9. • Receives impulses from head(CN V)and ear(CN VIII)

10. • Oral cavity(tongue,palate,oropharynx,epiglottis)

11. • Impulses from GIT and Heart

12. • Tela choroidea in the roof of myelencephalon invaginates
into the underlying cavity in the form of tufts forming
choroid plexus