Medulla

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

5. 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

6. 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

7. 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

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

9. 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 htt tp://www.vestib.com/medulla.html