THE HUMAN NERVOUS SYSTEM RAUL T. GARDAYA, M.D., FPNA, FPPA Assistan Professor I St. Luke’s College of Medicine William Quasha Memorial

OBJECTIVES Discuss the external anatomy of the cerebral hemispheres Identify the boundaries of the major lobes of the cerebral hemisphere Identify the important structures found in the major lobes of the cerebrum Discuss the functional anatomy of the different lobes Discuss the components and functions of cerebral cortex

OVERVIEW OF THE LEVELS OF THE NEURAXIS AND LONGITUDINAL SYSTEMS LEVELS OF THE NEURAXIS Supratentorial Posterior fossa CENTRAL NERVOUS SYSTEM Spinal Perpiheral Myoneural junction Organ

OVERVIEW OF THE LEVELS OF THE NEURAXIS AND LONGITUDINAL SYSTEMS LONGITUDINAL SYSTEMS Cerebrospinal Fluid Sensory Motor Internal Regulation Consciousness Vascular Neurochemical

SUPRATENTORIAL LEVEL Part of the CNS found within the skull and above the TENTORIUM CEREBELLI - Prosencephalic in origin - Telencephalon and diencephalon Telencephalon Diencephalon Tentorium Cerebelli

Diencephalon Telencephalon

TELENCEPHALON Components Cerebral hemispheres Cerebral Cortex Subcortical White Matter Basal ganglia Basal forebrain Ventral part of the basal ganglia Amygdala Nucleus basalis

The Cerebral Hemispheres

GALEN ( AD) Nervous tissue functioned like a gland. Nerves convey fluid secreted by the brain and spinal cord to the body’s periphery. Anterior brain for imagination, middle for reason and posterior for memory

LATE 1800’s CAMILO GOLGI Stained neurons with Silver salts Identified cell body, axons and dendrites SANTIAGO RAMON Y CAJAL Nervous tissue is not one continuous web but a network of discrete cells Laid the early foundations of the NEURON DOCTRINE - the principle that individual neurons are the elementary signaling elements of the nervous system

FRANZ JOSEPH GALL ( ) End of 18 th century All behavior emanated from the brain. Particular regions of the cerebral cortex controlled specific functions. The center for each mental function grew with use, much as a muscle bulks up with exercise. Phrenology

PHRENOLOGY  “ seat of the mind” (Greek)  Size, shape and bumps of the head determined the intelligence, sentiments and character of a person, including his future be it good or bad  “ seat of the mind” (Greek)  Size, shape and bumps of the head determined the intelligence, sentiments and character of a person, including his future be it good or bad

PHRENOLOGY

Cerebrum, INFERIOR SURFACE

Cerebral Cortex Neocortex Primary motor area Primary sensory area Association areas Paralimbic cortex Limbic cortex

CEREBRAL CORTEX

PIERRE PAUL BROCA Localization of the functions of the mind should be based on examining damage to the brain produced by clinical lesions rather than examining bumps on the head. Phrenology of convolutions, not a phrenology of bumps.

LAYERS OF THE CEREBRAL CORTEX

KORBINIAN BRODMANN Different functional areas of the cortex based on variations in structure of cells and in the characteristic arrangement of these cells into layers. Cytoarchitectonic method of classification

MAJOR FUNCTIONAL AREAS OF THE CEREBRAL CORTEX PRIMARY SENSORY CORTEX LOBELOBE SPECIFIC LOCATION Somatosensory Parietal Postcentral gyrus Visual Occipital Banks of calcarine fissure fissure Visual Occipital Banks of calcarine fissure fissure Auditory Temporal Heschl’s gyrus

PrimarySomatosensoryAreaPrimarySomatosensoryAreaPrimaryAuditoryAreaPrimaryAuditoryArea PrimaryVisualAreaPrimaryVisualArea

PrimarySomatosensoryAreaPrimarySomatosensoryAreaPrimaryAuditoryAreaPrimaryAuditoryArea PrimaryVisualAreaPrimaryVisualArea

THE BASAL GANGLIA AND SUBCORTICAL WHITE MATTER

SUBCORTICAL WHITE MATTER Projectional fibers Travel between cerebral cortex subcortical nuclear structures Internal capsule, corticospinal tract,

Commissural fibers Connect homologous areas in the two hemispheres Corpus callosum, anterior commissure, hippocampal commissure

Associational fibers Connect coritcal areas within hemispheres Uncinate fasciculus, cingulum, arcuate fibers

The Internal Capsule

The Diencephalon Thalamus Hypothalamus Epithalamus Subthalamus

THE THALAMUS Specific thalamic nuclei Nonspecifi c thalamic nuclei Midline nuclei Intralami nar nuclei Reticular nucleus

THE THALAMIC NUCLEI NUCLEUS Ventral anterior Ventral lateral Ventral posterior Medial geniculate Lateral geniculate Pulvinar Dorsomedial INPUT Globus pallidus Cerebellum Medial lemniscus Spinothalamic Tract Trigeminothalamic Tract Inferior colliculus Optic tract Superior colliculus Amygdala Prefrontal cortex Substantia nigra CORTICAL TARGET Supp motor area Motor area Primary sensory cortex Primary auditory cortex Primary visual cortex Association cortex Prefrontal cortex Anterior cingulate cortex

NUCLEUS Anterior Intralaminar Midline Reticular INPUT Mammillary bodies Hippocampus Spinothalamic tract Reticular formation Amygdala Hypothalamus Reticular formation Other thalamic nuclei Reticular formation Cerebral cortex CORTICAL TARGET Posterior cingulate cortex Striatum Diffuse cortical areas Anterior cingulate cortex Orbitofrontal cortex Other thalamic nuclei THALAMIC NUCLEI

NUCLEUS Periventricular zone Suprachaismatic Supraoptic and paraventricular Tuberoinfundibular Medial zone Medial preoptic Anterior Ventromedial Lateral zone FUNCTION Circadian rhythms ADH Oxytocin Releasing factors Thermoregulation Osmoregulation, sleep induction Food intake Cortical arousal, motivated behavior DYSFUNCTION Disruption of circadian rhytm DI, IADH Hypopituitarism, acromegaly Sexual precocity, amenorrhea Hypo-, hyperthermia Hypernatremia, thirst disorder, salt wasting syndrome, insomnia Obesity Hypersomnia, aphagia, adipsia HYPOTHALAMIC NUCLEI

Diencephalon Telencephalon Diencephalon Telencephalon Tentorium Cerebelli

The Limbic System Cingulate gyrus Subcallosal gyrus Hippocampal formation Parahippocampal gyrus Hippocampus Dentate gyrus Amygdaloid nucleus Mamillary bodies Anterior thalamic nuclei

The Limbic System Cingulate gyrus Subcallosal gyrus Hippocampal formation Parahippocampal gyrus Hippocampus Dentate gyrus Amygdaloid nucleus Mamillary bodies Anterior thalamic nuclei

The Limbic System Cingulate gyrus Subcallosal gyrus Hippocampal formation Parahippocampal gyrus Hippocampus Dentate gyrus Amygdaloid nucleus Mamillary bodies Anterior thalamic nuclei

LIMBIC SYSTEM Function Motivated behavior Learning Memory Higher order control of autonomic function Homeostasis Reproduction Emotion Cortical arousal Dysfunction Inability to learn Amnesia Inappropriate social behavior Emotional disturbances

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