Cerebellum MIMSA’s Anatomy sessions 2013 cerebellum •Motor part of the brain •Coordination of movement •Regulation of muscle tone •Maintenance of equilibrium •Ensures that there is contraction of the proper muscle at the appropriate time and with the correct force •Posterior cranial fossa •Separated from the occipital lobes by the tentorium cerebellum •Falx cerebelli placed deeply in the posterior cerebellar fissure •Fastigium constitutes the roof of the 4th ventricle http://bedahunmuh.files.wordpress.com/2010/05/fourth-ventricle-and-cerebellum.jpg •Longitudinally: 2 large bilateral hemispheres with vermis between them •Transversally: •Floccolonodular: at the edge of inferior surface; composed of paired irregular-shaped masses – flocula- joined medially by the nodulus (part of the vermis) •Anterior: rostral to the primary fissure. ATTENTION!2nd fissure to develop •posterior lobe: between primary and posterolateral fissures •Posterolateral fissure – between flocculonodular and posterior lobes. 1st fissure to develop http://www.netterimages.com/images/vpv/000/000/008/8291-0550x0475.jpg Gray and white matter •Gray matter: cortex + 4 types of nuclei in each side •White matter: medullary center + paired inferior, middle and superior cerebellar peduncles composed of afferent and efferent nerve fibers which connect the cerebellum with the medulla, pons and midbrain respectively Cerebellar cortex •Folia cerebelli •3 layers: •Molecular (stellate +basket) •Ganglionar (purkyne) •Granular (golgi cells + granular cells) •Layers have 5 types of cells: •Stellate •Basket •Purkyne •Golgi •granule http://vanat.cvm.umn.edu/neurHistAtls/pages/images/CNS9.jpg Cerebellar nuclei •Transmit all output from the cerebellum •Fastigial: close to the midline in contact with the fastigium •globulose: 2 or 3 masses in each side •Emboliform: oval shape •Dentate: most proeminent http://www.dizziness-and-balance.com/anatomy/images/cerebellar%20nuclei.jpg White matter •All the afferent (sensory) and efferent (motor) pathways pass through the peduncles. •Inferior cerebellar peduncle •Fibers entering the cerebellum with predominant origin in the inferior olivary complex – olivocerebelar tract; •Middle cerebellar peduncle •Fibers originating in the nuclei pontis / ponto cerebellar tract •Superior cerebellar peduncles •Fibers from globulose, emboliform and dentate nuclei. •Afferent fibers: superior spinocerebellar + rubrocerebellar tracts • http://o.quizlet.com/i/UGsmEwK4Cx5plxPJs_CD7Q_m.jpg Phylogenetical development •Archicerebellum – flocculonodular lobe: vestibular nuclei (major connection); function: posture and eye movement •Paleocerebellum – superior vermis in the anterior lobe + part of inferior vermis in the posterior lobe; spinal cord (major connection); function: progressive movement •Neocerebellum – ceberellar hemispheres + vermis in posterior lobe; cerebral cortex via ncl pontis (major connection); funtion: manipulative movement and speech http://classconnection.s3.amazonaws.com/917/flashcards/770260/png/cerebellum.png