Brain and Cranial Nerves: Organization, Functions, and Meninges, Slides of Dental Anatomy

Download Brain and Cranial Nerves: Organization, Functions, and Meninges and more Slides Dental Anatomy in PDF only on Docsity! Ch 15: Brain and Cranial Nerves  Discuss the organization of the brain, including the major structures and their functions  Describe the meninges of the spinal cord and brain, and integrate the formation and flow of CSF with this information.  Describe the structures that constitute the BBB and their functions  Review the cranial nerves, again giving a brief function of each. Docsity.com Major Brain Subdivisions  Telencephalon (= Cerebrum)  Diencephalon (Thalamus and hypothalamus)  Mesencephalon  Metencephalon (Pons and cerebellum)  Myelencephalon (= Medulla oblongata) Brainstem Docsity.com Arachnoid granulations: This is where the CSF produced in the choroid plexuses of the ventricles and which has circulated into the subarachnoid space is reabsorbed. Longitudinal fissure Docsity.com Four Ventricles CSF filled chambers Communicating with central canal of spinal cord Lined by ependymal cells Docsity.com CSF: Cerebro-Spinal Fluid  Formation in ventricles by specialized ependymal cells of choroid plexuses (~500 mL/day; total volume ~ 150 mL)  Functions – transport medium, in – shock absorption – buoyancy (floats the brain)  CSF circulation: Ventricles → central canal → subarachnoid space  Reabsorption into circulation via arachnoid granulations into superior sagittal sinus. Fig 15.6 Docsity.com Cerebral Hemispheres . . .  . . have functional regions (motor, sensory and association areas)  . . . have some functional differences (in spite of anatomical resemblance) → Lateralization of cortical functioning  . . . receive information and generate commands for opposite side of body Docsity.com Cerebral Cortex and Central White Matter Gray surface (cortex) with white tracts internally Commissures – connect corresponding gyri of the two hemispheres 1) corpus callosum 2) anterior commissure Projection tracts (fibers) – connect more or less vertically Association tracts (fibers) – connect one gyrus to another in the same hemisphere Docsity.com Basal (or cerebral) Nuclei Misnomer: basal ganglia Gray matter internal to the cerebral cortex, below floor of lateral ventricles. Function: modulate motor output from the cerebral cortex. Subconscious control of skeletal muscle tone and coordination of learned movement patterns. Parkinson's disease is caused by the loss of at least 80% of the dopaminergic neurons in basal nuclei and substantia nigra (resting tremor) Fig 15.11 Docsity.com Metencephalon: Cerebellum Hemispheres and lobes Cortex -gray surface with folia - fine ridges and sulci - grooves between the ridges Purkinje cells , axons of which become arbor vitae (white matter) in center Regulation of posture and balance Docsity.com Metencephalon: Pons Myelencephalon: Medulla oblongata  Mostly ascending and descending tracts  Nuclei of ori for many cranial nerves  Location of autonomic nuclei involved in respiratory and cardiovascular control  Relay stations for sensory and motor neurons Docsity.com Cranial Nerves  Twelve pairs: – 2 attach to forebrain (Telen- & Diencephalon) – 10 attach to brainstem (Mes-, Met- and Myelencephalon)  Names relate to appearance or function  Classification ? Docsity.com Oculomotor (N III) C: Motor O: Mesencephalon D: Somatic motor to superior, inferior, medial recti and inferior oblique; visceral motor to intrinsic eye muscles by way of superior orbital fissure Docsity.com Trochlear (N IV) C: Motor O: Mesencephalon D: superior oblique by way of superior orbital fissure Docsity.com Trigeminal (N V) C: Mixed three major branches 1. ophthalmic (sensory) 2. Maxillary (sensory) 3. Mandibular (mixed) O: face / nuclei of pons D: sensory nuclei in pons / muscles of mastication Docsity.com Tympanic cavity (middle ear) Tympanic membrane Semicircular canals branch (VIII) Vestibular Pharyngotympanic tube Cochlea Internal acoustic Facial nerve (VII), cut nerve (VIII) Cochlear branch (VIII) Vestibulocochlear 000 S) “I a2 2 a Docsity com Glossopharyngeal (CN IX) C: mixed O: sensory from posterior 1/3 of tongue / motor from medulla oblongata D: medulla / muscles for swallowing, parotid gland Docsity.com Vagus (N X) C: Mixed O: Sensation from pharyngeal area and outer ear / motor from medulla D: Sensory to medulla / visceral motor to thoracic and abdominal cavities and their organs. Major motor pathway for ANS Docsity.com