Chapter 2 a CNS Gross Anatomy l Chris

Chapter 2 a CNS Gross Anatomy l Chris Rorden University of South Carolina Norman J. Arnold School of Public Health Department of Communication Sciences and Disorders University of South Carolina 1

Multiple choice l What is the image plane? A. B. C. D. Axial. Coronal. Oblique. Sagittal. 2

Multiple choice l What is unusual about this brain? A. B. C. D. Too much gray matter Too much white matter Too much cerebral spinal fluid Too much bone 3

Roles of the CNS l Functions of neurons in the CNS (brain and spinal cord) include: – – Sensor: Receives environmental and body stimuli Integrator: Combines information received Effector: Initiates body movements Regulator: Maintains homeostatic state for body function 4

Nervous System l The CNS is protected and isolated. – Bone offers protection from injury l Skull covers brain l Vertebral Column covers spinal cord – – The is encased in soft-tissue membranes The brain’s blood vessels stop many subastances from entering the brain (blood-brain barrier) l Protects – from contamination/infection The brain floats in cerebral spinal fluid l Offers protection from impact 5

The Meninges l l l Dura Mater: Tough outer covering Arachnoid Mater: Middle layer Pia Mater: Inner closely formed layer l l l Latin - English Dura – strong Arachnoid – spider Pia – tender Mater -mother 6

Cerebrospinal Fluid (CSF) l l l Located between the meninges and in the ventricular cavities of the brain Produced in the ventricular cavities by the choroid plexus Functions – – mechanical buffer fluid for metabolic functions "Copyright © 2005 by Thompson Delmar Learning, a division of Thomson Learning, Inc. ALL RIGHTS RESERVED" 7

CSF l l CSF is in ventricles, subarchnoid space, interventricular foramens, and around the spine. Circulates from ventricles around brain and spinal column Is finally absorbed by venous system Replenishes at ventricles every 7 hours 8

Divisions of the PNS l Somatic Nervous System (under voluntary control) – – l Sensory and Motor Skin and Muscles Autonomic Nervous System (can not be voluntarily controlled). – – Sensory and Motor Visceral organs and glands Two main subdivisions: Sympathetic: Fight, Flight, Fear l – Prepare to expend energy Parasympathetic: Regulates normal function l Prepare to conserve energy 9

Major Structures of the Brain l Longitudinal Fissure – – Separates Two Hemispheres of the Brain Aka ‘Interhemispheric Fissure’ 10

l l The folds of your brain are like a fingerprint – there a few general patterns, with individual variability. Two main folds Central Sulcus Fissure of Rolando Rolandic sulcus – Lateral sulcus Sylvian fissure The central sulcus separates the frontal and parietal lobes. The lateral sulcus separates the temporal lobe from frontal, parietal, insula – l l 11

The major cortical lobes Insular Lobe – Tucked away, but often injured in patients seen by speech pathologists 12

Major medial sulci Central Sulcus Parieto-occipital Sulcus Calcarine Sulcus Preoccipital Notch 13

Landmarks of the frontal lobe Frontal Pole l Precentral Gyrus l Precentral Sulcus l Premotor Cortex l Speech, Fine Motor l Prefrontal Cortex l 14

Frontal Lobe Functions Motor Function l Cognitive Functions l Reasoning, Abstract Thinking, Self. Monitoring, Decision Making, Planning, Inhibition l Organization of Spoken Language l Frontal Motoric Areas 15

Broca’s Area – speech production Pars triangularis (Inferior fronal gyrus) Pars orbitalis (Inferior frontal gyrus) Pars opercularis (Inferior frontal gyrus) 16

Parietal Lobe Landmarks l Post Central Gyrus (Po. CG) – l Superior and Inferior Parietal Lobules (SPL, An. G, Sm. G) – l Primary Sensory Cortex Perceptual Synthesis, Spatial Orientation, Memory Angular Gyrus (An. G) Supramarginal Gyrus (SMG) – In Dominant Hemisphere: Reading, Writing and Calculation 17

The homunculus (little man) l The motor strip (red, frontal cortex) and primary sensory cortex (green, parietal) spatially map corresponding portions of the contralateral hemisphere. 18

Temporal Lobe – Major External Gyri Superior Temporal Gyrus l Middle Temporal Gyrus l Inferior Temporal Gyri l Temporal Pole 19

Temporal Operculum l Dorsal surface of STG is called the ‘Temporal Operculum’ (Lip) – Middle section: Heschel’s Gyri (Brodmann Areas 41 + 42) l – Auditory Reception Cortex Posterior section: Wernicke’s Area (Brodmann 22) l Auditory Association Cortex

Heschl’s Gyrus Primary auditory cortex found in Heschl’s gyrus l This is organized tonotopically – a high pitched sound excites a different region than low pitched sounds. l 21

Superior Temporal Gyrus Auditory Cortex lies inside the Superior Temporal Sulcus l Part of the superior temporal gyrus that is imperative for the perception of speech is Heschl’s gyrus l planum temporale (nonprimary AC) planum Heschl’s gyrus polare (primary AC) (nonprimary AC)

Ventral-Medial Structures l Temporal Lobe – – – l Fusiform gyrys (Face Recognition) Hippocampal Gyrus (places, memory) Uncus (smell) Occipital lobe – Cuneus and Lingual gyrus (primary vision) Medial View 23

Ventral-Medial Structures Uncus Parahippocampal Gyrus Fusiform Gyrus Lingual Gyrus Cerebellum and Brainstem removed 24

Occipital Lobe l Occipital Pole (medial) – – l Medially: cuneus and lingual gyrus: primary visual cortex Clinically: field cuts, blindsight Lateral occipital structures: – Superior, Lateral and Superior Occipital Gyris: Secondary Visual Cortex (Association) 25

Language Areas 26

Insular Lobe (Isle of Reil) l Deep in Lateral Fissure – Functions: Language(? ), taste, disgust, cravings (e. g. smoking)

Midsagittal Surface l Corpus Callosum – l Limbic System – l l Connects Hemispheres Emotions Cingulate Gyrus Fornix Thalamus Hypothalamus 28

Midsagittal Surface Corpus Callosum Cingulate Gyrus Septum Uncus Fornix 29

Transverse Slice Fornix Claustrum Putamen Caudate Nucleus Thalamus Globus Pallidus 30

Brain Stem Optic Nerve Midbrain Pons Medulla Optic Chiasm Optic Tract Pes Pedunculi Pituitary Stalk 31

Basal Ganglia l l l Caudate Nucleus Putamen Globus Pallidus (Pallidum) Caudate Nucleus +Putamen = Striatum Putamen + Globus Pallidus = Lenticular Nucleus 32

Striatum Head of Caudate Nucleus Cleft for Internal Capsule Thalmus Putamen Amygdaloid Nucleus Tail of Caudate Nucleus Lateral View 33