BIO153-B Ch12 Notes.docx - Chapter 12 – The Central Nervous...

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Chapter 12 – The Central Nervous System12.1 Folding during development determines the complex structure of the adult brain- brain and spinal cord begin asneural tube- rostraltoward the head (anterior)- caudaltoward the tail (posterior)secondary brain vesicles:- telencephalon (“endbrain”)- diencephalon (“interbrain”)- metencephalon (“afterbrain”)- myelencephalon (“spinal brain”)brain folds up to occupy available space because it grows morerapidly than the membranous skull that contains it-midbrainandcervicalflexuresmove forebrain toward brain stem- by week 26, continued growth of cerebral hemispheres causes theirsurfaces to crease and fold intoconvolutions(increase SA and allowmore neurons to occupy limited space)
1. Brain Regions and Organization (MISSING PAGE 437, ASK PROFESSOR OR SOMEBODY :c!!!!!!!!!!!!!!!!!!)-graymatter: short, nonmyelinated neuronsand neuron cell bodies-whitematter: mostly of myelinated axonswith some nonmyelinated axons, primarily in fiber tracts; dense coating offatty myelin is what gives white matter its color… where is figure 12.3 :C(1) spinal cord exhibits this basic pattern; pattern changes with ascent into the brain stem(2) brain stem has additional gray matter nuclei scattered within the white matter(3) cerebral hemispheres and the cerebellum have an outer layer or “bark” of gray matter called acortex2. Ventricles (WHERE IS FIGURE 12.4 T^T)-ventricles: continuous with one another and with central canal of the spinal cord- hollow ventricular chambers are filled with CSF and lined byependymal cells(type of neuroglia)- pairedlateral ventricles(one deep within each cerebral hemisphere): large C-shaped chambers that reflect the patternof cerebral growth; anteriorly, the lateral ventricles lie close together, separated only by thin median membrane called theseptum pellucidum (“transparent wall”)- each lateral ventricle communicates with the narrowthird ventriclein the diencephalon via a channel calledinterventricular foramen- third ventricleis continuous with thefourth ventriclevia the canal-likecerebralaqueductthat runs thru the midbrain-fourth ventriclelies in hindbrain dorsal to the pons and superior medulla; continuous with the central canal of thespinal cord inferiorly- three openings mark the walls of thefourthventricle:(1) the pairedlateralaperturesin its side walls(2)medianaperturein its roofconnect the ventricles to thesubarachnoid space(fluid-filled space surrounding the brain)
12.2 The cerebral hemispheres consist of cortex, white matter, and the basal nuclei< study this- Each of the cerebralhemispheres has three basicregions (Figure 12.3)- a superficialcerebralcortexofgraymatter, whichlooks gray in fresh brain tissue- internalwhitematter-basalnuclei, islandsof gray matter situated deepwithin the white matter***MISSING PAGES 441,442******

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Term
Fall
Professor
Bruce Prins

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