Medulla

1. Medulla
Stacy Sellner

2. Location and structure
The medulla oblongata the most inferior part of the brain
stem
Anterior median fissure – left/right
Rostral and caudal part – anterior/posterior
Dorsal median and dorsal intermediate sulcus
Contains pyramidal tracts and arcuate fibers which contains
corticospinal and corticobulbar tracts
In the pyramids there is decusation of motor fibers
Contains olivary body
Relays ascending sensory information to the cerebellum

3. Functions
Controls autonomic functions and reflexes
Breathing - controls through chemoreceptors
Heart rate, vasoconstricton/vasodilation via baroreceptors and
sympathetic and parasympathetic systems
Digestion via vagus nerve (stimulates HCl/peptin)
Sneezing via trigeminal nerve
Speech, swallowing/tongue movement via glossopharyngeal
nerve and hypoglossal nerve
Contains lots of motor and sensory tracts to relay information

4. Functions/Tracts
Synapse of (sensory) fasciculus gracilis (upper)/fasciculus cuneatus
(lower) occur in the medulla then travel to thalamus.
Dorsal column/medial leminiscus (sensory) - first order neurons
synapses in medulla
Discriminative touch and conscious proprioception
Rostral ventromedial medulla
Nociceptive information can be inhibited by binding of endorphins
or of analgesic drugs to receptor sites

6. More tracts through the Medulla
Medial corticospinal tract / Lateral corticospinal tract
Neck, shoulder, and trunk muscles / Fractionization, movement
of ipsilateral limbs
Corticobulbar
Voluntary control over cranial nerves, activation of descending
pathways and sensory processing.
Reticulospinal tract
Gross body movement and postural adjustments
Lateral vestibulospinal tract / Medial vestibulospinal tract
Postural muscles (center of gravity) / head movements

7. And some more...
Rubrospinal tract
Large muscle movement and fine motor
Spinothalamic
Conveys discriminative information about pain and temperature
Spinolimbic / spinomesencephalic / spinoreticular
Nonlocalized perception of pain; arousal, reflexive,
motivational, and pain blocking centers
Spinocerebellar
Conveys unconscious proprioceptive information

8. Disease/Injury to Medulla
Paralysis of the opposite side of the body
Loss of proprioception
Partial paralysis of tongue
Loss of pain and temperature sensation
Loss of gag reflex
Difficulty swallowing/vomiting
Vertigo
Loss of coordination
Severe injury can result in death by respiratory/cardiac arrest

9. https://www.youtube.com/watch?v=YH5tumYDmpg

10. References
Bailey, R. (n.d.). What is the medulla oblongata? Retrieved October 17, 2014, from
http://biology.about.com/od/anatomy/p/medulla-oblongata.htm
Gracile fasciculus. (2014, October 18). Retrieved October 20, 2014, from
http://en.wikipedia.org/wiki/Gracile_fasciculus
Lundy-Ekman, L. (2013) Neuroscience; Fundamentals for rehabilitation, 4th ed. St. Louis MO. Saunders,
Elsevier, Inc.
Medulla oblongata. (n.d.). Retrieved October 17, 2014, from http://www.healthline.com/human-body-maps/
medulla-oblongata
Swenson, R. (2006). Chapter 8A - Pyramidal system. Retrieved October 17, 2014, from
http://www.dartmouth.edu/~rswenson/NeuroSci/chapter_8A.html
The medulla oblengata. (n.d) Retrieved October 17, 2014, from htttp://www.vestib.com/medulla.html