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Tracts and nuclei of the medula oblongata

Tracts and nuclei of the medula oblongata. Márk Kozsurek, M.D., Ph.D. www.flickr.com/photos/ethanhein/2972774132/sizes/o/in/photostream/. ED II., 03/10/2017. lateral view. posterior view. Two sections through the medulla. Nuclei ( cell bodies of neurons – gray matter )

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Tracts and nuclei of the medula oblongata

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  1. Tracts and nuclei ofthemedulaoblongata Márk Kozsurek, M.D., Ph.D. www.flickr.com/photos/ethanhein/2972774132/sizes/o/in/photostream/ ED II., 03/10/2017

  2. lateral view posterior view Twosectionsthroughthemedulla

  3. Nuclei (cellbodies of neurons – graymatter) • cranialnervenuclei • sensory – somatosensoryorviscerosensory • motor – somatomotor, branchialmotororvisceromotor • othernuclei (notrelatedtocranialnerves) • Tracts (axons – whitematter) • ascendingsensory • desceding motor

  4. Sensory systems

  5. Motorsystems Pyramidal system simple structure voluntary movements Extrapyramidal tracts complex network body balance muscle tone automatic movements

  6. Originally sensory nerons are found in the dorsal portion of the neural tube (alar plate), while motor neurons occupy the ventral part (basal plate). As the fourth ventricle „opens up”, sensory nuclei migrate laterally and motor cells move dorsomedially.

  7. Medullaoblongatacaudal („closed”) part,approx. atthelevel of obex

  8. lateral view posterior view

  9. 2 sensory and 2 motor cranial nerve nuclei

  10. Sol STN XII Amb Sol: solitary nucleus Amb: ambiquus nucleus STN: spinal trigeminal nucleus

  11. Gr Cu Sol STN XII Amb inf. olivary nucl. Sol: solitary nucleus Amb: ambiquus nucleus STN: spinal trigeminal nucleus Gr: gracile nucleus Cu: cuneate nucleus

  12. Gr Cu stt Sol STN XII Amb STT medial lemniscus inf. olivary nucl. stt: spinal trigeminal tract STT: spinothalamic tract

  13. Gr Cu stt Sol STN XII Amb STT inf. olivary nucl. Py stt: spinal trigeminal tract STT: spinothalamic tract Py: pyramidal tract

  14. The caudal solitary nucleus (lateral nucl. of ala cinerea) receives general viscerosensory input from cervical, thoracic and abdominal organs. • Spinal trigeminal nucleus (general somatosensory nucleus of CNs V, VII, IX, X) receives protopathic information from the head via the spinal trigeminal tract which is constituted by the central axons of the pseudounipolar neurons of the corresponding ganglia. • Motoneurons within the hypoglossal nucleus (a general motor nucleus) innervate the muscles of the tongue and contribute to the innervation of the infrahyoid muscles. • Ambiquus nucleus is the branchialmotor nucleus of the CNs IX, X, XI contributing to the innervation of the striated muscles of the pharynx, larynx, esophagus.

  15. Gracile and cuneate nuclei are the brainstem relay nuclei of the dorsal column-medial lemniscus pathway conveying epicritic information. Fibres arising from these nuclei decussate and ascend close to the midline as the medial lemniscus toward the thalamus. • Spinothalamic tract (pain and heat sensation) arises from the dorsal spinal cord and terminates in the thalamus. • 80-90% of the pyramidal tract fibres decussate in the caudal medulla and descend in the lateral funiculus of the spinal cord.

  16. http://semmelweis.hu/anatomia/files/2014/04/Brainstem-sections.pdfhttp://semmelweis.hu/anatomia/files/2014/04/Brainstem-sections.pdf

  17. Medullaoblongatarostral („open”) part,accrossthehypoglossal and vagaltrigones

  18. lateral view posterior view

  19. One more cranial nerve nucleus!

  20. NDX: dorsal vagus nucleus inferior cerebellar peduncle NDX XII Sol STN Amb vagus n. hypoglossus n.

  21. NDX: dorsal vagus nucleus Gr inferior cerebellar peduncle Cu NDX XII Sol STN Amb vagus n. inf. olivary nucl. hypoglossus n.

  22. NDX: dorsal vagus nucleus Gr inferior cerebellar peduncle Cu NDX XII Sol dsc STN stt vsc STT Amb vagus n. medial lemniscus inf. olivary nucl. dsc: dorsal spinocerebellar tract vsc: ventral spinocerebellar tract hypoglossus n.

  23. NDX: dorsal vagus nucleus Gr inferior cerebellar peduncle Cu NDX XII Sol MLF dsc STN TST stt vsc STT Amb vagus n. ML inf. olivary nucl. Py dsc: dorsal spinocerebellar tract vsc: ventral spinocerebellar tract hypoglossus n.

  24. Withinthevaguscomplexbesidethesolitarynucleusthedorsalvagalnucleusappears. Thisgeneralvisceromotornucleusprovidesparasympatheticfibresfortheviscera of theneck, thorax and abdomen. • Inferiorolivarynucleus is mainlyinvolvedinextrapyramidalfunctions. • Dorsal (Flechsig) and ventral (Gowers) spinocerebellartractscarryproprioceptive and epicriticinformationfromthespinalcordtothecerebellum. • Medianlongitudinalfascicle (MLF) is a part of theextrapyramidalsystem, connectsthebrainstemgazecenters, thenucleiofC.N. III, IV and VI, thevestibularapparatusandthecervicalspinalmotoneuronsinnervatingthemuscles of theneck (coordinationofeye and headmovement). • Tectospinaltract (TST): extrapyramidalpatwayfromthesuperiorcolliculitothespinalcord, head and eyemovementco-ordination. Moving upward, what is new?

  25. http://semmelweis.hu/anatomia/files/2014/04/Brainstem-sections.pdfhttp://semmelweis.hu/anatomia/files/2014/04/Brainstem-sections.pdf

  26. Reticularformation Diffusenetwork of neuronsthatoccupiesthewholebrainstemaroundthe major descending and ascendingpathwaysandcranialnervenuclei. Motor functions(muscletone, posture, gaze, swallowing, breathing, vomiting, coughing, sneezing) Cardiovascularregulation Painmodulation ARAS: ascendingactivatingreticularsystem – consciousness, sleeping, arousal

  27. Three longitudinal columns of nuclei in the midline, medially and laterally.

  28. Thank you for your attention!

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