Medulla Oblongata

Medulla Oblongata

1. Inferior part of brain stem

   • Begins at foramen magnum, extends to pons (about 3cm)

2. Pyramids are protrusions formed by large corticospinal tracts that pass from cerebrum to spinal cord.

   • Just superior to the junction of medulla with spinal cord, 90% of axons in left pyramid cross to the right side and vice versa. This is called decussation of pyramids.

3. Nuclei in the medulla control & regulate the cardiovascular center & medullary rhythmicity area.

   • Cardiovascular regulates rate & force of heart beat & diameter of blood vessels
   • Rhythmicity area of the respiratory center adjusts the basic rhythm of breathing

4. Controls reflexes for vomiting, swallowing, sneezing, coughing and hiccupping.

5. Olive = olivary nucleus

   • neurons send input to cerebellum
     • proprioceptive signals
       • gives precision to movements

6. 5 cranial nerves arise from medulla - 8 thru 12