BIOM 3000 - Functional Mammalian Neuroanatomy Lectures PDF

Welcome to BIOM*3000 Functional Mammalian Neuroanatomy  Today’s Lecture Course Organization What is Functional Neuroanatomy? Cells of the Nervous System  How to get in touch with me? Dr. Tarek Saleh Professor and Chair...

Welcome to BIOM*3000 Functional Mammalian Neuroanatomy  Today’s Lecture Course Organization What is Functional Neuroanatomy? Cells of the Nervous System  How to get in touch with me? Dr. Tarek Saleh Professor and Chair Dept. of Biomedical Sciences OVC, Room 2633 Email [email protected] Office Hours OVC Main Building, Rm 2633 By appointment Teaching Methods Lectures: Every Monday & Wednesday at 2:30-4:20 (Room: MACN 113) Midterms during class time! Human Anatomy Lab: Monday, October 21st 6 sections: 10:00-11:00am, 11:15am-12:15pm, 12:30-1:30pm, & 1:45-2:45pm, 3:00-4:00pm, 4:15-5:15pm. Sign-up sheet in class! Case Studies: Problem based learning approach to Neuroanatomy Presentations during class (weeks 10 through 14; 3/class) Recommended Textbooks CourseLink BIOM*3000 Lecture Notes: Posted prior to each lecture, if notes are revised during class, updated notes will be posted following lecture Announcements: Check regularly for updates, changes in the schedule, etc. Discussion Boards: Course-related questions for your peers Case study groups Evaluation Assessment Type Weight Description Term Tests 15% Term Test #1 15% Term Test #2 *Case Study 20% Presentations starting Week 10 *Participation 10% Attendance case studies/peer reviews *Human Anatomy 5% Human Anatomy Lab tour Final Exam 35% Comprehensive/cumulative *If you are not present during the Anatomy tour or for any of the in-class case presentations, you will NOT be able to get the mark for that assessment (nor is there an opportunity to make up for the absence) Evaluation Term Tests (65%): 2 Midterms (15% each) scheduled inside of class time, (2:30-4:20) Final exam (35%) during finals period in Dec. Case Study (20%): Evaluation by Dr. Saleh – 15%; Intra-group peer assessment (if you receive a 3/5 or less from 2 or more members of your group, you presentation mark will be reduced by -10%) Accuracy of submitted flow chart – 5% Attendance at case studies (10%) – submission of peer review Anatomy lab tour (5%): Attendance at Human Anatomy lab – 5% Course Policies Attendance/Etiquette: Please be considerate of your fellow classmates Please turn off cell phone upon entering the classroom Recording of Materials Academic Misconduct LECTURE 1: INTRODUCTION TO NEUROANATOMY & CELLS OF THE NERVOUS SYSTEM Questions from midterm come from here Learning Outcomes By the end of today’s lecture, successful students will be able to: 1. Describe the localization of a brain structure using appropriate neuroanatomical terminology 2. List the principle cells of the nervous system 3. Describe the functions of each of these cells 4. Explain how to visualize cells of the nervous system What is Neuroanatomy? The study of the anatomy and organization of the central nervous system(s) of animals. the core fetsandright Correia fsidengf.fi Radial symmetry Bilateral symmetry Neuroanatomical Terminology http://what-when-how.com  Planes of Section Coronal Sagittal Horizontal Front & back Left & right Top & bottom MSU, Brain Biodiveristy Bank Neuroanatomical Terminology Anterior/Posterior (front/back) “ante” à before, belly in humans “post” à after, back in humans Medial/Lateral (inside/outside) “medius” à middle, and “lateralis” à to the side Superior/Inferior (top/bottom) “superior” à above, head in humans “inferior” à below, feet in humans Dorsal/Ventral aka superior/inferior (“top/bottom”) Rostral/Caudal aka anterior/posterior (“front/back”) sagittalplane Neuroanatomical Terminology ventral anterior dorsal posterior interchangable Coronal frontalplane Nolte: Essential of the Human Brain Figure 3.1  Nervous System Classification Nervous system Peripheral Central nervous Nervous system system (Cranial nerves) Brain Spinal Cord Autonomic Somatic (optic nerve) in Sympathetic Parasympathetic Central Nervous System (CNS) Brain & spinal cord White matter oflipids composed Myelinated axons Gray matter Cell bodies & dendrites http://study.com transverse plane  Cells of the Nervous System Neurons Convey information through electrical & chemical signals Oldest & longest cells Functional unit of behaviour Martone et al. CIL:40124 Limited ability to be replaced Cell Image Library Glia Provide a support system for the neurons both physicalandmetabolicsupport Variety of types & functions Presence is crucial for neurons www.novusbio.com Anatomy of a neuron deffee toteaches i onlyinPNS  Neuron Morphology Part Description Major Organelles Primary Function Dendrites Tapered extension(s) Cytoskeleton Primary site of of the cell body Mitochondria reception Complex (branching) Soma 1 or more processes, Nucleus Synthesis of (Cell Body) generally 1 axon & ER & Golgi macromolecules many dendrites apparatus Cytoskeleton Integration of Mitochondria electrical signals Axon Single, cylindrical Cytoskeleton Conduction of the processes Mitochondria action potential May have myelin Transport Vesicles Axon Terminal Vesicle-filled opposed Mitochondria Neurotransmission to another neuron Synaptic Vesicles adf.sn ation i  Neurons are Polarized Functional and anatomical polarization Regardless of the type of neuron, signaling occurs in an organized, consistent manner Neuron Classification Can be classified based on structure: (Dendrites branch off axon): Unipolar Pseudo-unipolar Bipolar (Dendrites branch off cell body): Multipolar Kandel –Principles of Neural Science 5th ed. Figure 2-3  Neuronal Classification – function! concegmuspongwareness 1. Sensory Pns CNS dorsalrootganglion (afferent) CNSSPNS 2. Motor (efferent) 3. Preganglionic Autonomic 4. Postganglionic Autonomic 5. Interneuron augtghgfoi sqng.IS 6. Projection Infifolyays Nolte: Essentials of the Human Brain Figure 1-3 Visualization of Neurons Golgi Staining oldest Silver staining technique for use under light microscopy Potassium dichromate & silver nitrate blackprecipitates  Golgi Staining Fainandcertainonesdon't gottatithe Stains a limited number of cells at random Camillo Golgi (1843 - 1926) Santiago Ramón y Cajal (1852 - 1934) Together won in 1906 Noble Prize in Medicine for their work on the structure of the nervous system  Visualization of Neurons Golgi Staining Silver staining technique for use under light microscopy Potassium dichromate & silver nitrate Immunohistochemistry Localization of proteins (antigen) using antibodies to specific proteins Example: NeuN, MAP2, synaptophysin, PSD95 specific for neurons s.EEftIhere each GFAP (Glial fibrillary acidic protein) for astrocytes  toamplify a signaladd Immunohistochemistry a 2nd antibody Wikipedia: Immunohistochemistry brownprecipitate Detection methods: 1. Chromogen: alkaline phosphate, horseradish peroxidase 2. Fluorescence: FTIC, TRITC, Alexa Fluors Visualization of Neurons Golgi Staining Silver staining technique for use under light microscopy Potassium dichromate & silver nitrate Immunohistochemistry Localization of proteins (antigen) using antibodies to specific proteins Example: NeuN, MAP2, synaptophysin, PSD95 GFAP (Glial fibrillary acidic protein) for astrocytes Neuron filling Via injection or axonal transport Example: biotin derivatives, GFP, lucifer yellow, Viruses (pseudo- rabies/herpes), etc. Neuron Filling/Tracers Targeted filling of neurons of interest Take advantage of polarity & transport mechanisms within the cell Methods for loading Microinjection pipetteintobrain a micro Whole-cell patch clamping Mcgstmmon Electroporation so Ian  Glial Cell classifications chanical support “Glia” à Greek for “glue” 2 metabolicsupport Function to support neurons Are not electrically excitable buttheyhave a restingmembrane potential all cellsdo Fontyneurons muscles 5 major cell types Schwann cells PNS mythate Oligodendrocytes Astroglia CNS Microglia Ependymal cells Thought to be more abundant than neurons (5:1)... Fiction!  HHS Public Access Author manuscript J Comp Neurol. Author manuscript; available in PMC 2017 December 15. Published in final edited form as: 1 ratio J Comp Neurol. 2016 December 15; 524(18): 3865–3895. doi:10.1002/cne.24040. neurons glial cells The Search for True Numbers of Neurons and Glial Cells in the Human Brain: A Review of 150 Years of Cell Counting Christopher S. von Bartheld1,*, Jami Bahney1, and Suzana Herculano-Houzel2 1Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA 2Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, and Instituto Nacional de Neurociência Translacional, CNPq/MCT, Brasil Abstract For half a century, the human brain was believed to contain about 100 billion neurons and one trillion glial cells, with a glia:neuron ratio of 10:1. A new counting method, the isotropic fractionator, has challenged the notion that glia outnumber neurons and revived a question that was widely thought to have been resolved. The recently validated isotropic fractionator demonstrates a glia:neuron ratio of less than 1:1 and a total number of less than 100 billion glial cells in the human brain. A survey of original evidence shows that histological data always supported a 1:1 ratio of glia to neurons in the entire human brain, and a range of 40–130 billion glial cells. We review how the claim of one trillion glial cells originated, was perpetuated, and eventually refuted. We compile how numbers of neurons and glial cells in the adult human brain were reported and we examine the reasons for an erroneous consensus about the relative abundance of glial cells in human brains that persisted for half a century. Our review includes a brief history of cell counting in human brains, types of counting methods that were and are employed, ranges of previous estimates, and the current status of knowledge about the number of cells. We also discuss implications and consequences of the new insights into true numbers of glial cells in the human brain, and the promise and potential impact of the newly validated isotropic fractionator for reliable quantification of glia and neurons in neurological and psychiatric diseases. INDEXING TERMS  Schwann Cells Principle glial cell of the PNS Metabolic support oneschwannef Wrap around individual axons to form myelin sheath (electrical insulation) PNS axon regeneration axon one Schwann cell per http://what-when-how.com  Oligodendrocytes Myelinating cells of the CNS Multiple processes allow one oligodendrocyte to surround multiple axons Wikipedia: Oligodendrocytes © K.-A.Nave/MPI f. Experimental Medicine Astrocytes Most abundant glial cell in CNS (75%) Mechanical support of neurons Scaffold Metabolic support (glycogen) Regulation of extracellular fluid (K+, neurotransmitters) Contact with CNS blood vessels Reactive astrocytes following injury/insult  Microglia (10-15%) Smallest glia cells Major role in CNS response to injury Healthy CNS Survey for damage/disease Activation by inflammation Activated microglia non- phagocytic Transformation to macrophage (phagocytic)  Ependymal Cells Line the ventricular system CSF of the brain & central canal of spinal cord Ciliated to aid movement of CSF Specialized ependyma produces CSF brain Choroid plexus Regenerative? filterstood makes CSF Medical Dictionary, © 2009 Farlex & Partners as of rn yes the onlyone bothhere Next Lecture… Action Potentials and the Synapse & Introduction to Case Studies Twitter: @Cartoon_Neuron after a thousand  somatic inhibits pain signal could be a higher or lower threshold it depends on the neuron  intracellular the leak channels bring it back to 70 no ATP is used  find don't Na K and channels do but you find calcium channels is a direct result of  LECTURE 3: NERVOUS SYSTEM EMBRYOLOGY & DEVELOPMENT From last class… From last class… calcium voltage gated channels open 1 1. Production 2. Packaging 3. Release 4. Binding 5. Termination Learning Outcomes By the end of today’s lecture, students will be able to: 1. Describe the process of primary neurulation 2. Explain how neurogenesis, cell migration, and recessive events are involved in nervous system development 3. Describe the divisions of the spinal cord and their functional roles 4. Identify the types of cells that are derived from the neural crest peripherial Nerves neural tube ons Embryology – Germ Layers Endoderm Gut, liver, lungs Mesoderm Skeleton, muscle, kidney, heart Ectoderm Skin & nervous system both CNS PNS Origins of CNS/PNS development CNS Induction by mesoderm of the ectoderm to form “neuroectoderm” fusestomake Neural plate à neural tube Neural tube gives rise to brain & spinal cord (rostral and caudal respectively) anterior Yosterior PNS Diverse sources Neural crest cells Neural tube: preganglionic autonomic nerves & motor neurons Mesoderm: meninges and connective tissue surrounding peripheral nerves Primary Neurulation 3rd - 4th week of development induces Notochord (mesoderm) induces overlying ectoderm to differentiate into neuroectoderm Neurulation Induction of ectoderm to differentiate by mesoderm Development of the neural tube, running the length of the embryo Primary Neurulation Flat neural plate begins to fold forming paired neural folds Folds fuse together gradfatgs beginning in neck area & itdown continues in both directions to form neural tube Cells on edge of neural plate form neural crest cells (PNS) Cells of the Nervous System Ectoderm M part of PNS comes out of the neural crest in PNS Nolte: Essentials of the Human Brain Fig. 2-2 Notochord turns into we don't know Errors in Neurulation in the closing of the neural tube Spina Bifida Incomplete closure of caudal end of neural tube Range in severity of defect Occulta ~5% of population Incomplete closure of vertebrae Meningocele I beningn Myelomeningocele Bait shingles Most severe reform Spinal cord & meninges in sac-like fillswest cavity on back needgsery cYq na Errors in Neurulation M in complete closure of rostral end of baby fell break his Encephalocele brain tuff neural Sac-like protrusion of brain & surrounding membranes Anencephaly Incomplete closure of the rostral end of the neural tube Lack of telencephalon (cerebrum) The Early Neural Tube cells 9 Ventricular zone Neural progenitor cells Neuroblasts & glioblasts Intermediate/Mantle zone Accumulation of neurons & glial cells Grey matter cell body Marginal zone Cell poor Neuronal & glia processes https://clinicalgate.com White matter ax my feed Fways  Spinal Cord Development Sulcus limitans separates sensory & motor of spinal cord 7 DJosition Dorsal portion à alar I plate Sensory FIT Ventral portion à basal plate Motor Spinal Cord Development (CAUDAL neural tube) T Motor neurons from basal plate send projections to muscle Dorsal root ganglion É (DRG) send projections both centrally and tic peripherally Spinal Cord Development Summary adult development dorms n I ventral Grey matter horn sulfismitans  Brain Development (ROSTRAL neural tube) As the neural tube closes, it forms a series of 3 bulges (primary vesicles) Prosencephalon Mesencephalon Rhombencephalon Brain Development 52 Secondary vesicles Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon Ventricular system Yffbrain midbrain fuggebrthien Continuous with central canal of spinal cord in brain call it ventricular fluid spinalcord ends brainbegins Coronal view 1 Pepydggglrce of stemcells produces Iggy p Entre 3 Y l Brain Development Telencephalon grows a Choroid greater rate than other plexus vesicles C-shaped arc of growth around insula Primary sulci form GW14- stays therest 26 fund ofgtrhowest.gr Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 1.8 sagitfftion  Coronal section cortical Colamic fipple to hypothalamus Thalamus and corpus striatum develop first Corpus striatum “sliced” into caudate and lentiform/lenticular nucei by corticothalamic fibres sevenaffin Corona radiata newsynapses  Cell Proliferation Neurogenesis Proliferation of neural progenitors Ventricular zones (VZ) Adapted from Howdeshell (2002) Envir Health Perspect 110  Neuronal Migration Skull Most neurons produced in VZ migrate radially Somal translocation Guided by radial glial cells Tangential migration Medial & lateral ganglionic eminence I Inhibitory cortical interneurons Short inner neurons 9bioddieffoffeir finalresting Ventricle spot Luhmann et al. (2015) Front Cell Neurosci. 9 Programmed Cell Death Two important “regressive events” in brain development 1. Apoptosis Neuronal populations lost prenatally Up to 70% in some cortical areas Mechanism for correcting errors? Eliminating transient cell populations (ie. marginal zone & subplate) Glial populations lost postnatally Loss of excess oligodendrocytes during myelination  2. Synaptic Exuberance & Pruning Massive production of synaptic connections followed by loss of up to 50% of the synapses Largely postnatal, over months or years Mechanisms Neurotrophic support Afferent input Huttenlocher (1990) Neuropsychologia 28 Why you can’t remember life as a baby Hippocampal neurogenesis Excessive ‘rewiring’ of connections (“plasticity”) Hippocampus is still growing during childhood  Neural Crest Cells – PNS development Develop from cells on lateral aspect of neural plate Highly proliferative Differentiate into a number of neural and non-neural tissues Migrate throughout the embryo Two types: cranial & trunk Differentiation of Neural Crest Cells  Dorsal Root Ganglion Provide sensory we A information from the body Synapse with sensory neurons within the dorsal horn Schoenwolf & Smith (1990) Development 109 Autonomic Nervous System 2 neuron system: preganglionic & postganglionic Sympathetic Nervous System (“Fight or Flight”) Preganglionic: Basal plate at thoracic & lumbar level Postganglionic: Neural crest derived neurons with cell bodies in sympathetic chain ganglia (close to spinal cord) Exception: Chromaffin cells of adrenal medulla, neural crest derived Parasympathetic Nervous System (“Rest & Digest”) Preganglionic: Basal plate of brain stem & sacral level Postganglionic: Neural crest derived neurons with cell bodies close to the organs of innervation Autonomic Nervous System Visceral organ sensory and motor function Differ in : Length of pre vs postganglionic neurons Neurotransmitter at postganglionic cell  Abnormal Neural Crest Cells all balls are Neurocristopathies: a diverse class of nitens F nerves ectoderm fucked up pathologies involving e cells derived from the neural crest Neurofibromatosis Cleft lip & cleft palate Waardenburg Syndrome aka albinism Nervous System Repair Wide variety of regenerative capacities Leopard gecko Can regenerate functional tail following tail loss Developing mammals Some, lost over time making spinal cords Adult mammals Limited PNS is better at regenerating dev.biologists.org then CNS  PNS Repair/Regeneration Neurons lost to disease/injury generally not replaced Axon transection Wallerian degeneration Schwann cell proliferation Increased RNA synthesis in neuron If innervation successful, function is restored Nolte: Essentials of the Human Brain Figure 24-9 CNS Repair/Regeneration Neurons lost to disease/injury generally not replaced Adult neurogenesis (ependymal cells!) Subgranular zone of the hippocampus Subventricular zone of lateral ventricles Axon transection Wallerian degeneration freventby Astrocytes and oligodendrocytes actively impede regeneration Glial scar: reactive astrocytes secrete chondroitin sulfate proteoglycans (CSPGs) Joint health its Cartlidge  Case Study/Anatomy lab Tour If you are currently not assigned to a case study group, please come see me at the end of lecture. Same for Human Anatomy Sign-up!  LECTURE 4: GROSS ANATOMY OF THE CNS & THE MENINGES From last class… 1. What are the 3 major Germ layers and what cells arise from each? 2. What are the 2 major segments of the spinal cord and what functions relate to each? 3. Main form of cell proliferation and site of migration? apoptosis 4. How is CNS cell number controlled? synaptic 5. Do CNS cells regenerate in adult pruning mammals? A little tiny bit the epydemal cells i Stem cells From last class… ee i.i.ie i.ie e.e.ie Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 1.3 Spinal Cord Development Summary I matter grey cell bodies Spinal Cord Development Summary Grey matter brain 2 White matter Grey matter Spinal cord 2 thalamus thalamus Learning Outcomes By the end of today’s lecture, students will be able to: 1. List the 5 major lobes of the cerebrum and ascribe their basic functions 2. List the major internal cerebral nuclei 3. Describe the divisions of the diencephalon and brainstem 4. Describe the 3 meningeal layers and explain the differences between cranial and spinal meninges Neuroanatomical Terminology Cephalic flexure right at thalamic nucleus Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 1.3 Major CNS Divisions Mid-sagittal section purplet Dog anger MY  surface area The Cerebrum more mfre neurons more glial cells L DeFelipe (2011) Front Neuroanat. doi: 10.3389/fnana.2011.00029 Hemisphere Connectivity golgi stain 2 major connective tracts between hemispheres Corpus callosum Interconnects most cortical areas Anterior commissure Connection between temporal lobe cortical regions Coronal section through mouse be smooth Sulcus & Gyrus Sulcus (Sulci) Depression or groove Deep sulci à fissures 7 Gyrus (Gyri) Ridge or fold between two sulci Increase surface area of lobe cortex/cerebrum Provide important landmarks hippocampus learning memory  frommidline to tempora lobe Sulci separates frontal lobe from parieth 4 major sulci Lateral surface Central sulcus (of Rolando) Lateral sulcus templobe fr offthe brain Aka. Sylvian fissure Medial surface Parietoocciptal sulcus Cingulate sulcus Cingluate Names of other sulci are sulcus Parietooccipital derived from their location sulcus within cerebral lobes/location to major sulci Gyri s Gyri are named in relation to the sulci they are beside Examples: Precentral gyrus vs. Postcentral gyrus Superior, middle & inferior frontal gyrus Correspond to Adapted from Henry Gray: Anatomy of the Human Body (1918) functional areas  Lobes of the Cerebrum 4 major sulci define the boundaries of the cerebral lobes 5 lobes Frontal (pink) Parietal (blue) Occipital (yellow) Cingluate sulcus Parietooccipital sulcus Temporal (green) Limbic (purple)  central sulcus parietooecipita sulcus lateralis or Sylivan Fissure cingulate sulcus  Central Cingulate Sylvian Parietooccipital  Functional Anatomy of Cerebrum Frontal Lobe: Motor functions à precentral gyrus contain primary motor cortex Broca’s area à production of written & spoken language Parietal Lobe: Somatosensory information à postcentral gyrus contains primary somatosensory cortex Functional Anatomy of Cerebrum Occipital Lobe: Vision à contains primary visual & association cortices Temporal Lobe: Superior temporal gyrus à primary auditory cortex Wernicke’s area à comprehension of language  The Limbic Lobe (System) Telencephalon/cerebral structures Cingulate gyrus & parahippocampal gyrus Hippocampus Amygdala Diencephalon structures Thalamus Hypothalamus Role in emotional responses & memory Wikipedia: Limbic System  Internal Cerebral Anatomy Limbic System nuclei Amygdala (Am) Hippocampus (HC) sat Basal Ganglia Globus pallidus (GP) o o Caudate (C) Putamen (P) Diencephalon Thalamus (Th) Hypothalamus (H) Nolte: Essentials of the Human Brain Figure 3-6 Basal Ganglia & Internal Capsule Roles in eye movement, motivation & working memory Internal capsule: fibres interconnecting cerebral cortex to thalamus & basal ganglia x Adapted from MSU Brain Biodiversity Bank Fitzgeralds Clinical Neuroanatomy & Neuroscience Figure 2.11 Internal capsule (slide 22, Lect #3!)  Diencephalon Thalamus Gatekeeper to the cortex All sensory information (except olfactory) passes through thalamus Hypothalamus Autonomic nervous and neuroendocrine control Pineal Gland (Epithalamus) Endocrine gland Produces melatonin Nolte: Essentials of the Human Brain Figure 3-3  Brainstem Iii ÉÉ l Midbrain Toptic Hindbrain Pons Midbrain id Medulla Attachment point for most Pons cranial nerves Cranial nerve reflexes Long tract functions Medulla Ascending reticular anasthenia attacks activating system Consciousness awareness Fitzgerald’s Clinical Neuroanatomy and Neuroscience Figure 3.2A Cerebellum I Longitudinal divisions Vermis 2 Cerebellar hemispheres 3 lobes Anterior Ventralview Posterior 3 f Flocculonodular (oldest) Functions Coordination of trunk & limb movements Eye movements Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 3.16 Meninges of the Brain & Spinal Cord 3 layers Dura mater Arachnoid mater Pia mater Provide mechanical support of the CNS Cerebrospinal fluid (CSF) filled subarachnoid space Dura Mater toughmother Thick, tough, collagenous Falx cerebri membrane dorsal Fused with the endosteum (inner periosteum) of the Tentorium cerebelli skull ventral Adheres to underlying arachnoid https://clinicalgate.com Dural septa (folds) Falx cerebri 1stfold left aPnÑiJnsthemisphere Tentorium cerebelli separatescerebellum Dura Mater With few exceptions, spaces do not exist on either side of the dural membrane Two potential spaces Epidural: between cranium and outer dural surface Subdural: within innermost dural layer, near arachnoid boarder* Dura mater contains venous sinuses that drain the brain superiorsaggitalsinus Superior sagittal sinus arachnoidvilli Left and right transverse sinuses Straight sinus Arachnoid Mater Superior saggitalsinus Thin, avascular membrane in direct contact with dura mater Arachnoid trabecula: small strands of collagenous connective tissue within subarachnoid space Give arachnoid mater its spider web-like appearance Arachnoid villi: small protrusion through dura mater into venous sinuses Reabsorption of CSF into venous system  Subarachnoid Cisterns byspinal cord Large pockets of subarachnoid space filled with CSF Major cisterns (4) – interpeduncular, pontine, quadrigeminal and cisterna magna. Stores CSF  Pia Mater “Tender” mater Thin, connective tissue layer in direct contact with surface of CNS Contact with arachnoid trabecula on other side Cerebral arteries & veins surrounded by pia before entering/exiting the brain Perivascular space  Meninges & the Spinal Cord Same meninges as those surrounding the brain with a few important differences 1. Vertebral canal contains an epidural space between periosteum & dura 2. Pia mater gives rise to longitudinal denticulate ligaments à spinal cord anchor 3. Lumbar cistern at caudal end of spinal cord Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 4.10 Next Lecture... The Ventricular System, CSF, & Blood Supply  LECTURE 5: VENTRICULAR SYSTEM, CSF & BLOOD SUPPLY I Dr. Tarek Saleh protects Cushions the BIOM*3000 brain not the circulatory system From last class… Eneia FYI Subarachnoid Space & Cisterns Filled with cerebrospinal fluid (CSF) From last class… Dura mater contains the venous sinuses that drain the brain Superior sagittal sinus Left & right transverse sinuses Straight sinus Learning Outcomes By the end of this lecture, students should be able to: Describe the flow of CSF through the ventricular system Explain the role of the choroid plexus A inathetommygab Draw & label the circle of Willis & component arteries Name the major arteries that supply the cerebrum and cerebellum Describe the 3 components of the blood brain barrier Ventricular System Embryology the floor Central Canal Spinal Cord  Ventricular System titties psi p Lateral Ventricles (2) Paired, C-shaped structures 5 parts (frontal, occipital & SUPT Fal temporal horns, body & atrium) Interventricular Foramen suppliesoccipital Third Ventricle Boarded by thalamus & hypothalamus supplies temporal lobe Ventricular System Aqueduct (of Sylvius) Fourth Ventricle Located in the hindbrain “space” between cerebellum and the pons & medulla Communication with subarachnoid space via 3 apertures (recess) Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 2.22 CSF Ventricular Flow push ayato o id g para En subs “Drainage” of CSF back into circulation  Choroid Plexus produces CSF epydemyal cells Lines lateral ventricles, pass through IV-foramen, & roof of 3rd ventricle Separate strand in 4th ventricle Component of blood-brain barrier black parts Damkier et al. (2013) Phys Rev 93:1847-1892  1 Choroid Plexus Specialized area where ependymal cells & pia mater are in direct contact Specialized ependymal cells à choroid epithelium Apical surface tight junctions Choroid Plexus Increased surface area through folding Total surface area > 200cm2 Rate of formation 350 μL/minute 500 mL/day Relatively constant Christensen et al. (2013) Front. Physiol.  Hydrocephalus “Water on the brain” CSF is constantly produced Excess CSF production or Blockage of circulation or Deficient CSF reabsorption lateral ventricles t in size be CSF production is here and constant Hydrocephalus Enlargement of ventricle Compression of brain tissue Symptoms: Headache, vomiting, nausea, papilledema, sleepiness, coma Infants: bulging of cranium Treatments: Placement of shunt to drain into lumbar system Hydrocephalus A young child presents with aqueductal stenosis (a narrowing of the aqueduct) due to a midbrain tumor. Which ventricular areas are/aren’t affected? lateral ventricles and the third ventricle Brain Circulation Neurons lack the ability to store energy & oxygen Brain uses about 15% of normal cardiac output Consumes 25% of the body’s oxygen Loss of consciousness after just 10 seconds without perfusion Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 6.19  Arterial Blood Supply Internal carotid arteries (ICA) Branch of common carotid arteries Bifurcates into middle and anterior cerebral arteries (MCA & ACA) Blood supply for most of the cerebrum Children’s Hospital of Wisconsin  Arterial Blood Supply Vertebral arteries Branch of subclavian arteries Fuse at pontomedullary junction to form basilar artery Branches form posterior cerebral artery (PCA) & multiple cerebellar arteries Blood supply for brainstem, parts of cerebrum & spinal cord Children’s Hospital of Wisconsin  ACA: Anterior Cerebral Artery Circle of Willis MCA: Middle Cerebral Artery ICA: Internal Carotid Artery PCA: Posterior Cerebral Artery abbreviate can't 888 on Connection between internal carotid and vertebral-basilar arterial systems Posterior communicating artery: ICA to PCA Anterior communicating artery: connects ACA branches  Functions of Circle of Willis Normally, little blood is moved along anterior and posterior communicating arteries If one major vessel either within or proximal to the circle of Willis becomes occluded, the communicating arteries allow for perfusion of distal tissue I Most effective when occlusion Nolte: Essentials of the Human Brain occurs slowly over time Figure 6-4 ensures constant perfusion of the brain even if theres a blockage Cerebral Arteries –Medial Surface Anterior cerebral artery (ACA) Medial surface of frontal & parietal cortices, corpus callosum Posterior cerebral artery (PCA) Temporal cortex & some occipital cortex Cerebral Arteries –Lateral Surface go1 of inclusive Strokes happen here where the middle cerebral artery splits Middle Cerebral Artery (MCA) 60-80% of blood flow from internal carotid artery (ICA) Upper division: Frontal & parietal cortices Lower division: Temporal & occipital cortices Deep Brain Structures Anterior choroidal artery (AChA) Branch of the internal carotid artery Blood supply of optic tract, choroid plexus of inferior lateral ventricle, thalamus & hippocampus Perforating (ganglionic) branches Small branches off of ACA, MCA or PCA Blood supply of basal ganglia, internal capsule & diencephalon Often compromised during stroke Stuff that breaks off block from main clot can easily these Posterior choroidal arteries (PChA) Branches of the posterior cerebral artery Supply choroid plexus of lateral & 4th ventricle Blood Supply to Hindbrain Midbrain Posterior cerebral artery Pons AICA, SCA, along with multiple pontine arteries Medulla PICA, along with anterior & posterior spinal arteries Cerebellum 3 cerebellar arteries (AICA, PICA & SCA) Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 5.10  Venous Return 2 sets of veins drain the brain Superficial veins Lie on surface of cerebral hemispheres Drain to superior sagittal sinus Deep veins Drain structures in the walls of the ventricles Converge on internal cerebral veins Nolte: Essentials of the Human Brain Drainage to straight sinus Figure 6-6 Venous Drainage mums Nolte: Essentials of the Human Brain Figure 6-7 Sagittal & straight sinus drain into transverse sinuses Transverse sinus à sigmoid sinus à internal jugular vein Vascular problems involving veins less common than arterial problems  Regulation of blood flow Normal blood flow: ~55mL/100g brain per minute 3 major mechanisms Autoregulation Blood vessels constrict/relax to maintain constant flow Local responses excitatory neurotransmitter Example: Glutamate release from neurons Binds to receptors on astrocytes à release of vasodilators Results in local increase in blood flow 3 Autonomic control leasteffective Least important regulatory factor May play role in longer term adaptations (i.e. stress)  Angiography Injection of a radiopaque dye into the artery of interest, followed by radiographic imaging every 1-2 seconds Identification of vascular pathologies such as aneurysms Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 5.7 Aneurysms Balloon-like swellings of the arterial walls Most often formed at or near arterial branch points Consequences Compression of brain tissue I a bifurcate Rupture à subarachnoid Smythe weaker hemorrhage balloon yikes www.health.auckland.ac.nz Cerebrovascular Accident/Stroke Most common cause of neurological deficits Reduction in blood flow à neuronal malfunction or death Ischemic stroke Sudden blockage of blood flow Early treatment can limit permanent damage to affected areas Transient ischemic attack (TIA)/mini-stroke Hemorrhagic stroke Arterial rupture, often of small perforating arteries Signs & symptoms determined by region(s) affected  Blood Brain Barrier annoyingrights 1 barrier Regulates the composition of CSF/flow of components to/from plasma 2 egptg.la Separates extracellular space of CNS from that of rest of body 3 Prevents diffusion into subarachnoid space from Nolte: Essentials of the Human Brain outside the CNS Figure 6-5 Blood Brain Barrier on Er as sina.EE iii paced I blood Kandel’s Principle of Neural Science Figure D-1 Circumventricular Organs (CVOs) Locations where the cerebral capillaries are fenestrated & allow for relatively free communication Located around the 3rd and 4th ventricles sickness Sensory organs right under 4th ventricle morning this Area postrema: monitors blood for toxins, induces vomiting grayffpg Vascular organ of the lamina terminalis (OVLT): regulation of fluid balance Subfornical organ Secretory organs Median eminence of hypothalamus & posterior pituitary: neuroendocrine role secretes hormones into circulation Pineal gland: secretion of melatonin biological Clock Location of 5 CVOs Sensory CVOs Secretory CVOs Next Lecture… The Spinal Cord & Spinal Tracts  on computer 4 Sideofthe stimulus see need  face gets sensation from Kean Mdd mesodermal tissue surrounding neural tube accommodates arms accommodates legs  no MH efferent motor autonomic  afferent neurons runs the entire Tayotthe Spinal cord  folds frefolds  Very organized has to has 6 7 8 9 10 Proprioceptor knowing where ur limbs are in space found in joints at a at  comingfrom primary sensoryafferent mid ventral motorn sensory crossover happens in the brain all sensory info goes through this  immediately crosses rub it  LECTURE 7: DESCENDING SPINAL TRACTS & THE CRANIAL NERVES From last class… Face not represented! From last class… Dorsal median sulcus Dorsal funiculus Dorsolateral sulcus Dorsal horn Intermediate Lateral Gray funiculus Ventral horn Ventrolateral sulcus Ventral funiculus Ventral medial fissure  From last class… developedspecies inolderspeciesmorephylogeneticallyancient onlyinhigher pDorsal column-medial lemniscal Spinothalamic (anterolateral) tract (DCML) temp pain dorsalcolumn proprioception and touch Learning Outcomes By the end of today’s lecture, students will be able to: A 1. Describe the major descending spinal tract 2. Explain the consequences of a given spinal cord injury 3. Describe the organization of cranial nerve nuclei 4. Explain the function of the sensory and motor cranial nerves Ind Combined not just the 12 DESCENDING SPINAL TRACTS Descending Tracts Descending pathways influence the activity of lower motor neurons Two neuron chain Upper motor neuron (UMN) Cell body within the motor cortex (precentral gyrus) Responsible for descending inhibition onto LMN whyyoubefore distract Lower motor neuron (LMN) you exs Cell body in spinal cord, axons project to target organ/muscle Final common pathway of the motor system Spinal Cord Damage Symptoms determined by region affected Spinal cord transection or upper motor neuron (UMN) disease removes the decending inabition Initial period of spinal shock à flaccid paralysis & areflexia Followed by hyperreflexia excessive exagerated reflex Example: Babinski’s sign: Dorsiflexion of big toe & fanning of others in response to stimulus along the bottom of foot Lower motor neuron (LMN) disease Flaccid paralysis Areflexia Muscle atrophy (wasting due to lack of use)  Spinal cord segments and consequence of a lesion If the lesion is between: C1-C5: UMN signs to all 4 limbs M hyperflexi a to all 4limbs loss of all decending inhabit i on C6-T2: UMN signs to Legs; LMN to Arms It iii at T3-L3: UMN signs to Legs; normal Arms L4-S2: LMN signs to Legs; normal Arms UMN “sign” = hyperreflexia LMN “sign” = areflexia, muscle atrophy, paralysis Kill the nerve *To test if unilateral or bilateral damage, test PAIN on R + L sides Case examples Signalment and history: 4 yr old male presents 1 week after a car accident with complaints of back pain. Physical Exam: slightly obese, no other abnormal findings. Neuro Exam: Muscle atrophy in both arms MN Loss of proprioception in LA the DCML pathway Left side deficient Loss of pain sensation in LA the Ac pathway Hyperreflexia in both legs UMN Answer C6 T2 UMNSignstoLegs MN to Arms Neuroanatomical diagnosis? bilateral both arms t legswere affected Case examples Signalment and history: 4 yr old male presents 1 week after a car accident with complaints of back pain. Physical Exam: slightly obese, no other abnormal findings. Neuro Exam: Muscle atrophy in both arms – LMN in BOTH arms! Loss of proprioception in LA Indicated LEFT-sided deficits Loss of pain sensation in LA Hyperreflexia in both legs – UMN in BOTH legs ANSWER: LMN signs in both arms UMN in both legs C1-C5: UMN signs to all 4 limbs C6-T2: UMN signs to Legs; LMN to Arms T3-L3: UMN signs to Legs; normal Arms L4-S2: LMN signs to Legs; normal Arms ANSWER: LMN signs in both arms UMN in both legs Hit By Car (HBC) resulting in C6-T2 compression (bilateral…how do we know this?) BOTH arms and legs are affected! Another case example Signalment and history: 4 yr old male presents with complaints of inability to use right leg. Progressed rapidly over last 4 hours. PE: Bright, alert, responsive, no other abnormal findings NE: Normal mentation, cranial nerve reflexes, and forelimb (arm) reflexes. LMN Paralyzed right leg (RL). Decreased muscle tone to RL, areflexia in RL with normal pain perception in BOTH legs. crossesimmediately Notes: LMN RL; normal on left side (unilateral or bilateral?...test “sensation”/pain) If LMN, what level of spinal cord likely affected? 24 52 paralyzed leg but can stillfeelpain cellbody or nervedamaged ofmotor neuron  C1-C5: UMN signs to all 4 limbs C6-T2: UMN signs to Legs; LMN to Arms T3-L3: UMN signs to Legs; normal Arms L4-S2: LMN signs to Legs; normal Arms ***LMN (L4-S2) on right side*** Peripheral motor nerve or motor neuron cell body in spinal cord innervating right leg. Sensation is normal in both legs, so not a spinal problem! THE CRANIAL NERVES  Cranial Nerve Classification Nosuchthingas an autonomicsympatheticcranialnerve Sensory (Afferent) Motor (Efferent) 1. General somatic 1. General somatic Pain, temperature & touch Muscles of orbit & tongue 2. General 2. General visceral/autonomic visceral/autonomic norf abtdomal Parasympathetic Parasympathetic section 3. Special sensory 3. Special visceral/brachial Taste, balance & hearing Brachial arch musculature of face, jaw, palate, larynx, pharynx HAL The Cranial Nerves Bonesensorstmotor Memorize Labored land use roman numerals Cranial Nerve Nerve Type (Sensory, Mnemonics Motor, Both, Autonomic) I Olfactory S “On Old II Optic S Oklahoma’s Towering Top, A III Oculomotor M (A) Fine Vet Gladly IV Trochlear M Viewed A Horse” V Trigeminal B VI Abducens M “Six Sailors Made VII Facial B (A) Merry But My Brother Said Bad VIII Vestibulocochlear S Business My IX Glossopharyngeal B (A) Man” X Vagus B (A) (A) = III,VII, IX, X XI Accessory M XII Hypoglossal M 3 7 9 10Autonomic Cranial Nerve Functions Cranial Nerve CRANIAL Function(s) I Olfactory Smell (olfaction) II Optic Vision III Oculomotor Eye movements, pupil, lens IV Trochlear Eye movements (superior oblique) V Trigeminal Facial sensation, chewing VI Abducens Eye movements (lateral rectus) VII Facial Facial expressions and taste VIII Vestibulocochlear Hearing and balance IX Glossopharyngeal Taste and swallowing X Vagus Viscera sensing, speaking & swallowing XI Accessory Head and shoulder movement XII Hypoglossal Tongue movement  Cranial Nerve Attachments one two are missing morerostral Attachment Point I Olfactory bulb II Optic chiasm III Rostral midbrain (V) IV Midbrain/pons junction (D) V Pons (L) VI Pontomedullary junction (V) a VII Pontomedullary junction (V/L) VIII Pontomedullary junction (V/L) floorof4thventricle IX Rostral medulla (L) ÉÉÉhoid X Rostral medulla (L) prefers XI Cervical spinal cord (L) gtf Yetrekellum XII Rostral medulla (V/L) Nolte: Essentials of the Human Brain Figure 12-1 Brainstem Cranial Nerve Nuclei sensory Like the spinal cord, brainstem nuclei are generally located in motor predictable areas Sensory nuclei are more dorsal Motor nuclei are more ventral Visceral nuclei closer to sulcus limitans (Special visceral, general visceral, General somatic, etc) Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 17.1  Brainstem Cranial Nerve Nuclei Sensory more lateral motor more media Associated with one or more cranial nerves If the nerve carries both sensory & motor information, it will have more than one nucleus H Ex. Vagus (X) All nuclei supply ipsilateral nerves Exception: Trochlear (IV) TE contralateral Nolte: The Human Brain eye Figure 12-2 What you need to know… 1. What type of information (S,M, B, A) does each cranial nerve carry? 2. What is the function of each cranial nerve? 3. Where does each cranial nerve enter/exit the CNS? 4. Where are the cranial nerve nuclei located? Sensory Nerves Olfactory (I) Smell Optic (II) Sight Vestibulocochlear (VIII) Vestibular nerve: balance/equilibrium Cochlear nerve: hearing vestibulecochlear Olfactory Nerve – CN I Begins in olfactory epithelium inside nasal cavity Contains bipolar receptor cells with long axons that form CN I Unmyelinated axons smell neverkilledyou Group into small bundles à olfactory fila diffgroups theiraxonsformtheolfactorynerve Project directly to olfactory bulb Outgrowth of telencephalon Olfactory receptors replaced throughout life Nolte: Essentials of the Human Brain **Does not project to thalamus! Figure 13-4 Olfactory Tract Olfactory tract fibers from olfactory bulb project to: Primary olfactory cortex (piriform & periamygdaloid cortices) of temporal cortex Amygdala Smell can provoke memory vice versa Olfactory tubercle Thalamus involved in projections from piriform cortex to olfactory association cortex (orbitofrontal) Combines with gustatory information odor combines w Deficits in olfaction Conductive: anosmia nose.is tworkingwhe Sensorineural: anosmia sick 3tosgtme can't taste be can't problem recognize w receptors  Optic Nerve – CN II Retina in multi-layered structure converting light into action potentials 1. Photoreceptors (rods & cones) 2. Bipolar cells 3. Ganglion cells Axons form optic nerve receptors are at thebackoftheeye Nolte: Essentials of the Human Brain Figure 17-2  Optic Chiasm & Optic Tract Partial decussation of optic nerve in optic chiasm Temporal Temporal Axons of nasal half cross midline Nasal Foggy nefoss Joins uncrossed fibers in optic tract andIIIs Travels to lateral geniculate nucleus (LGN) of thalamus Optic radiation projects to ipsilateral primary visual cortex (calcarine sulcus) L R  Visual System Damage l = left visual field r = right visual field l r l r L R 1. Optic nerve Damage affects ipsilateral eye 2. Optic chiasm r l r l Damage affects crossing fibers Damage affects half of visual field (left field of left eye, right field of right eye) Left visual field from L eye Right visual field from R eye 3. Optic tract (right side) (affects crossing fibers only) Damage affects left visual field of both eyes L R Left visual field lesion Nolte: Essentials of the Human Brain (green lines both eyes) Figure 17-5 Vestibulocochlear Nerve – CN VIII Hearing & balance/equilibrium Two branches: Vestibular Proprioception & head position Cochlear Hearing goes to pond Vestibular Nerve Utricle & saccule Static labyrinth Linear acceleration Semicircular canals (3) Kinetic labyrinth rotation angular of the head Angular acceleration Vestibular Nerve MGMcaus Vestibular nerve projects to vestibular nuclei Some direct projections to cerebellum Nuclear projections to: Thalamus à parietal cortex The Vestibulospinal tracts (medial and lateral) Brainstem nuclei of cranial nerves III, IV and VI eyeball (Vestibulo-ocular reflex; VOR – reflex that matches head and eye movements) Cochlear Nerve Transduction of sound waves from outer ear à middle ear à movement of inner ear fluid Bending of hair cells in Organ of Corti Inner hair cells: principle source of sound information Outer hair cells: control of sensitivity Cochlear Nerve mix of hearing between sides Auditory information is distributed bilaterally within the CNS can triangulate Sounds VPL third nucles Motor Nerves Oculomotor (III) Trochlear (IV) Abducens (VI) III, IV & VI all involved in eye movements Accessory (XI) Head & shoulders Hypoglossal (XII) Tongue  The Ocular Motor Nerves Nerves Oculomotor (III) Trochlear (IV) Abducens (VI) Roles The 4 recti and 2 oblique muscles controlling eye movements Levator of upper eyelid Sphincter of the pupil and the ciliary muscle  Oculomotor Nerve – CN III Oculomotor nucleus (rostral Younienntherategemove them to midbrain) for together Series of subnuclei Ipsilateral: inferior rectus, inferior oblique, medial rectus Contralateral: superior rectus Edinger-Westphal nucleus (rostral midbrain) Parasympathetic fibers innervate the ciliary and sphincter pupillae muscles Pupillary light reflex (oculomotor Dx) Abnormal pupillary light response - an inappropriate lack of constriction of the pupil. its role is to constrict I dialation is a of the ability to broken be constrict massive light out Trochlear Nerve – CN IV Trochlear nucleus (caudal midbrain) supplied contralateral superior oblique Nerve exits via the dorsal surface of the brainstem So eyeballs match Abducens Nerve – CN VI Fuses abduction of the eye the Abducens nucleus (caudal i cut cross eye pons) innervates the lateral rectus Abduction of the eye Examples of Clinical Disease: Medial strabismus and loss of lateral gaze. Inability to retract globe. Next Class… Motor (cont...) and Mixed Cranial Nerves LECTURE 8: MOTOR AND MIXED CRANIAL NERVES Dr. Tarek Saleh BIOM*3000 From last class… The Cranial Nerves Classification based on the type(s) of information they carry All, except I and II, attach within the brainstem Brainstem nuclei are found in predictable locations based on the type of information they are responsible for Motor nuclei are found in medial area Sensory nuclei are found in lateral area Visceral (sensory & motor) are found at boundary between motor & sensory  From last class… Sensory Cranial Nerves Olfactory (I) à Smell/olfaction Receptor: Bipolar cells in olfactory epithelium Projections to primary olfactory cortex, amygdala & olfactory tubercle Secondary projection to orbitofrontal cortex Optic (II) à Sight Receptor: Multi-layered retina (Photoreceptors, bipolar, ganglion) Nerve à chiasm à tract to LGN of thalamus subsection of nucleus Optic radiation to primary visual cortex VPLnucleus as well  From last class… Vestibulocochlear (VIII) Vestibular nerve Receptor: hair cells in utricle, saccule & semicircular canals Information (Utr, Sac): linear accelerations & head position Information (Canals): angular acceleration Vestibular nuclei projects to ocular motor system & spinal cord Cochlear Receptors: hair cells within the Organ of Corti Information: Sound à travelling waves through cochlea Cochlear nuclei project bilaterally to thalamus (MGN) onto the auditory cortex 3ʳᵈ Subnucleus From last class… Motor Cranial Nerves All control the eyeball Oculomotor (III) Oculomotor nucleus à inferior rectus, inferior oblique, medial rectus & superior rectus Edinger-Westphal nucleus à ciliary muscle & sphincter pupillae Trochlear (IV) Trochlear nucleus supplies contralateral superior oblique Abducens (VI) Abducens nucleus supplies medial and lateral rectus Fuctthe eye PLR?? Learning Outcomes By the end of today’s class, students will be able to: 1. Define the cranial nerves by the type(s) of information they carry 2. Describe the 5 motor cranial nerves 3. Describe the 4 mixed cranial nerves What you need to know… 1. What type of information does each cranial nerve carry? 2. What is the function of each cranial nerve? 3. Where does each cranial nerve enter/exit the CNS 4. Where are the cranial nerve nuclei located? Motor Nerves Oculomotor (III) Trochlear (IV) Abducens (VI) Accessory (XI) Head & shoulder movements Hypoglossal (XII) Tongue movements  Accessory Nerve (CN XI) shrugs Accessory nucleus located in upper portion of cervical spinal cord Innervation of ipsilateral sternocleidomastoid (SM) and trapezius Function: shrugging shoulder & turning head to contralateral side Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 18.4  Hypoglossal Nerve (CN XII) Hypoglossal nucleus along midline of medulla close to the floorof the 4thventricle Innervation of extrinsic and intrinsic muscle of tongue Supranuclear innervation Corticobulbar fibers from primary motor cortex: Fine movements like articulation Reticular formation: eating & swallowing What-when-how.com Hypoglossal Nerve Damage Bothsidescontract toward the midline sowhenyoustick your tounge out straight Supranuclear damage Transient weakness of contralateral muscle Tongue deviates away from side of damage Crossed projection Nuclear or nerve damage Weakness and atrophy of ispilateral muscle Tongue deviates toward side of damage Wikipedia: Hypoglossal Nerve Mixed Cranial Nerves Trigeminal (V) Facial sensations Chewing Facial (VII) Facial expressions Glossopharyngeal (IX) Taste & swallowing Vagus (X) Principle parasympathetic nerve Taste, swallowing & speaking  Trigeminal Nerve (CN V) deeper structures Very large sensory territory including skin of the face, mucous membranes, teeth, dura mater & intracranial blood vessels Motor innervation to muscle of mastication (chewing), tensor timpani, tensor palati, mylohyoid & diagastric f muscle g mm 59 fistconcert  Trigeminal Nuclei -Sensory Mesencephalic nuclei Only CNS nucleus to contain unipolar sensory neurons Peripheral process to face, central process to supratrigeminal nucleus (motor) Pontine (principle) nuclei Tactile information from face & oronasal cavity Spinal nucleus Sensory afferents from mouth Nociceptive & thermal information Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 21.2 Facial Nerve (CN VII) Blink menacereflex r whensomeoneclaps in yourface Motor innervation to muscles involved in facial expressions and the stapedius (middle ear) Parasympathetic outflow to secretory glands in s eyes, nose & mouth glands Sensory input from tongue & palate (gustatory) Nolte: Essentials of the Human Brain Figure 12-8  Facial Nerve –Main Facial Nerve Facial motor nucleus Motor supply for muscles Nerve loops around abducens nucleus before leaving brainstem Supranuclear innervation All cell bodies receive coticobulbar innervation from contralateral motor cortex Muscle of upper face also receive ipsilateral innervation Role is paired activities I.e. wrinkling foreheard Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 22.1 Facial Nerve Lesions Supranuclear Contralateral motor weakness of lower face Nuclear Complete facial (and abducens) paralysis on side of lesion (1,2,3) Nerve Ex. Bell’s palsy Complete facial paralysis on side of lesion Unable to raise eyebrow, Bell’s palsy close the eye or retract lip Fitzgerald’s Clinical Neuroanatomy & Neuroscience Figure 22.3  Glossopharyngeal Nerve –CN IX Primarily a sensory nerve, carrying information from the viscera Somatic sensation from the outer ear Parasympathetic innervation of the parotid gland salivarygland Motor innervation of the stylopharyngeus Swallowing & speaking  Glossopharyngeal Nuclei -Sensory Solitary nucleus Visceral sensory input from taste buds (posterior third of tongue), carotid body, carotid sinus & mucous membranes Spinal trigeminal nucleus Pain from pharynx and posterior third of tongue Somatic sensory input from outer ear  Glossopharyngeal Nuclei -Other Inferior salivary nucleus Parasympathetic innervation of the parotid gland (salivary gland) Nucleus ambiguus Branchial/special visceral efferent innervation of stylopharyngeus Tswanowingmuses  Vagus Nerve (CN X) grffresstentation Most widely distributed cranial nerve “vagus” à wandering Primary parasympathetic nerve to thoracic & abdominal viscera Sensory afferents and motor efferents to and from thoracic and abdominal viscera Visceral reflexes peristalsis  Shares nuclei nerve Vagus Nerve Nuclei W glossopharengyl Dorsal motor nucleus Preganglionic parasympathetic neurons that innervate viscera Nucleus ambiguus Preganglionic parasympathetic innervation of heart & some other thoracic organs Branchial motor innervation of larynx and pharynx Gag reflex where parasympathetic preganglicneurons originate both yellow t red Vagus Nerve Nuclei Solitary Nucleus Special sensory innervation from taste buds of epiglottis & esophagus Visceral sensory information from thoracic & abdominal viscera, larynx and pharynx Spinal trigeminal nucleus Visceral afferents from larynx, esophagus and pharynx Taste –CN VII, IX and X End Notle: Essentials of the Human Brain Figures 13-1 and 13-3 Interesting facts about thalamic relay nuclei: Optic goes to LGN Tenthate nuc Vestibulocochlear goes to MGN Olfaction goes to Dorsomedial nucleus of thalamus and then to VPM where it mixes with taste input ventral posterialmedial Trigeminal, glossopharyngeal and vagus go to VPM (vagus also goes to VPL) In general, sensation from body (spinothalamic and DCML)= VPL, face = VPM Smell + taste = gustatory = VPM VPM projects to inferior salivatory nucleus = salivation Next Class… Human Anatomy Tour !!