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StuDocu is not sponsored or endorsed by any college or universityChapter 14 - The Brain and Cranial NervesHuman Anatomy And Physiology II (College of Staten Island CUNY)StuDocu is not sponsored or endorsed by any college or universityChapter 14 - The Brain and Cranial NervesHuman Anatomy And Physiology II (College of Staten Island CUNY)Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Chapter 14 - The Brain and Cranial Nerves14.1 - Overview of the BrainMajor Landmarksrostral- toward the foreheadoanteriorcaudal- toward the spinal cordoposteriorcoronal-(or frontal) sectioning into ventral-dorsal planessagittal-sectioning from left to rightbrain weighs abouto1,600 g (3.5 lb) in men, ando1,450 g in women3 major portions of the brain:ocerebrum- is 83% of brain volumecerebral hemispheres,gyri and sulci,longitudinal fissure, andcorpus callosumocerebellum- contains 50% of the neuronssecond largest brain regionlocated in posterior cranial fossaobrainstem- the portion of the brain that remains if the cerebrum and cerebellum are removeddiencephalon,midbrain,pons, andmedulla oblongatalongitudinal fissure- deep groove that separates cerebral hemispheresgyri- thick foldssulci- shallow groovescorpus callosum- thick nerve bundle at bottom of longitudinal fissure that connects hemispheres1Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
the brain occupies theoanterior cranial fossa,omiddle cranial fossa,andoposterior cranial fossacerebellumoccupiesposterior cranial fossaomarked bygyri, sulci, and fissuresseparated from cerebrum bytransverse cerebral fissureoabout 10% of brain volumeocontains over 50% of brain neurons2Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
brainstem- what remains of the brain if the cerebrum and cerebellum are removedomajor components:midbrainponsmedulla oblongata3Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Gray and White Mattergray matter- the seat of neuron cell bodies (neurosomas), dendrites, and synapsesodull white color when fresh, due to little myelinoforms surface layer(cortex)over cerebrum and cerebellumoformsnucleideep within brainwhite matter- bundles of axonsoliesdeep to cortical gray matter,opposite relationship in the spinal cordopearly white color frommyelinaround nerve fibersocomposed oftracts,or bundles of axons, that connect one part of the brain to another, and to thespinal cord4Downloaded by Katya Zamolodchikova ([email protected])lOMoARcPSD|4395810
Embryonic Developmentnervous system develops fromectodermoectoderm- outermost tissue layer of the embryoearly in third week of developmentoneuroectoderm -dorsal streak appears along the length of embryoothickens to formneural platedestined to give rise to most neurons and all glial cells except microglia, which comefrom mesodermas thickening progressesoneural plate sinks and its edges thickenforming aneural groovewith a raisedneural foldon each sideneural folds fuse along the midline, creating a hollowneural tubeby day 26

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