Central Nervous System Review

Dendrites Axon Body/Soma Synapse NEURON Neuron Parts  1. Which structure receives messages? 2. Which structure sends messages? 3. Which structure contains the nucleus? 4. What location of the neuron will contain the released neurotransmitters? Dendrites Axon Body/Soma Synapse Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Copyright © 2008 Pearson Education, Inc Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Central Nervous System The brain and spinal cord Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Spinal Cord Conus medullaris Filum terminale Cauda equina 8 12 A B The inferior end of the spinal cord Filum terminale Long filament of connective tissue Attaches to the coccyx inferiorly Cervical and lumbar enlargements Where nerves for upper and lower limbs arise Cauda equina Collection of spinal nerve roots 8 12 A B 5 C 5 Coccyx =1 Figure 13.2a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Spinal Cord Two deep grooves run the length of the cord Protected by vertebrae, meninges, and CSF Meninges Dura mater – a single layer surrounding spinal cord Arachnoid mater – lies deep to the dura mater Pia mater – innermost layer Denticulate ligaments – lateral extensions of pia mater Two deep grooves run the length of the cord Posterior median sulcus Anterior median fissure A B C Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Gray and White Matter of the Spinal Cord Gray matter Shaped like the letter “H” Gray commissure – contains the central canal Dorsal horns Consist of interneurons Ventral and lateral horns Contain cell bodies of motor neurons White matter - Outer region of the spinal cord - Composed of myelinated and unmyelinated axons Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Anatomy of the Spinal Cord Gray matter Gray commissure Ventral horn Lateral horn Dorsal horn A B C D Figure 13.4b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Gray Matter of the Spinal Cord and Spinal Roots Divided according to somatic and visceral regions SS – somatic sensory VS – visceral sensory VM – visceral motor SM – somatic motor Figure 13.5 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Embryonic Development of the Brain Primary brain vesicles (4-week old embryo) Prosencephalon – forebrain Mesencephalon – midbrain Rhombencephalon – hindbrain Secondary brain vesicles Prosencephalon telencephalon and diencephalon Mesencephalon – remains undivided Rhombencephalon Divides into metencephalon and myelencephalon Adult Telencephalon cerebral hemispheres Diencephalon thalamus, hypothalamus, and epithalamus Mesencephalon midbrain Metencephalon pons and cerebellum Myelencephalon medulla oblongata Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Embryonic Development of the Brain Divided into four regions Cerebral hemispheres Diencephalon Brain stem Midbrain, pons, and medulla Cerebellum Figure 13.7a–e Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Basic Parts and Organization of the Brain Figure 13.9 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Basic Parts and Organization of the Brain Centrally located gray matter Externally located white matter Additional layer of gray matter external to white matter Due to groups of neurons migrating externally Cortex – outer layer of gray matter Located in cerebrum and cerebellum Figure 13.10 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Ventricles of the Brain Lateral ventricles – located in cerebral hemispheres Horseshoe-shaped from bending of the cerebral hemispheres Third ventricle – lies in diencephalon Connected with lateral ventricles by interventricular foramen Cerebral aqueduct – connects 3rd and 4th ventricles Fourth ventricle – lies in hindbrain Connects to the central canal of the spinal cord A A D D C C B B Figure 13.11a, b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem Includes the Midbrain Pons Medulla oblongata Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Several general functions The Brain Stem Several general functions Produces automatic behaviors necessary for survival Passageway for all fiber tracts running between the cerebrum and spinal cord Heavily involved with the innervation of the face and head 10 of the 12 pairs of cranial nerves attach to it Which CN do NOT attach to brain stem? CN I – Olfactory CN II - Optic Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Ventral View of the Brain IDENTIFY: Olfactory bulb Optic nerve Optic tract Optic chiasma Mamillary body Midbrain Pons Medulla oblongata Spinal cord G F E D C B A Figure 13.12 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – Medulla Oblongata Is continuous with the spinal cord 1)Choroid plexus lies in the roof of the fourth ventricle 2)External landmarks of medulla =Pyramids of the medulla (Lie on its ventral surface) =Decussation of the pyramids (Crossing over of motor tracts) Figure 13.13a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – Medulla Oblongata 2)External landmarks of medulla =Inferior cerebellar peduncles (Fiber tracts connecting medulla and cerebellum) =Olive (olive of the medulla; Contains inferior olivary nucleus) =Cranial nerves VIII–XII attach to the medulla *VIII – Vestibulocochlear *IX – Glossopharyngeal nerve *X – Vagus nerve *XI – Accessory (Spinal Accessory – a branch of the vagus nerve) *XII – Hypoglossal nerve Where is CN III – VII located? CN V, VI, VII at the PONS CN III, IV at the MIDBRAIN Figure 13.13b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Several general functions The Brain Stem Several general functions Produces automatic behaviors necessary for survival Mid-brain & Pons CN III, IV, VI – Eye movement and pupillary reflex CN V, VII – Innervation of the face and head Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Medulla Oblongata The core of the medulla contains Much of the reticular formation (influence autonomic functions) Visceral centers of the reticular formation include Cardiac center Vasomotor center The medullary respiratory center Centers for hiccupping, sneezing, swallowing, and coughing Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Pons A “bridge” between the midbrain and medulla oblongata Pons contains the nuclei of cranial nerves V – Trigeminal nerve VI – Abducens nerve VII – Facial nerve The pons contains Motor tracts coming from the cerebral cortex Pontine nuclei Connect portions of the cerebral cortex and cerebellum Send axons to cerebellum through the middle cerebellar peduncles Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Midbrain Lies between the diencephalon and the pons Cerebral peduncles located on the ventral surface of the brain Figure 13.13a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Midbrain Superior cerebellar peduncles Connect midbrain to the cerebellum Figure 13.13b Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Midbrain Periaqueductal gray matter surrounds the cerebral aqueduct Involved in two related functions Fright-and-flight reaction Mediates response to visceral pain Cerebral aqueduct The central cavity of the midbrain Figure 13.21 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Midbrain (Dorsal View) Corpora quadrigemina The largest nuclei Divided into the superior and inferior colliculi Superior colliculi – nuclei that act in visual reflexes Inferior colliculi – nuclei that act in reflexive response to sound Figure 13.13c Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Brain Stem – The Midbrain Imbedded in the white matter of the midbrain Two pigmented nuclei Substantia nigra – neuronal cell bodies contain melanin Red nucleus – lies deep to the substantia nigra Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Diencephalon Composed of: 1) Thalamus – process and relay information to the cerebral cortex 2) Hypothalamus – visceral control system 3) Epithalamus (pineal gland) – secretes melatonin (induces sleep) Figure 13.13c Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Cerebellum C B A Located dorsal to the pons and medulla Smoothes and coordinates body movements Helps maintain equilibrium C B A Consists of two cerebellar hemispheres Surface folded into ridges called folia Separated by fissures Hemispheres each subdivided into Anterior lobe Posterior lobe Flocculonodular lobe (tiny) Figure 13.15a Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

The Cerebellum Composed of three regions Cerebellar Cortex – gray matter Arbor vitae Internal white matter Deep cerebellar nuclei – deeply situated gray matter Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Cerebral Hemispheres HEMISPHERES • Left side: words and logic • Right side: art, music, intuition Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

BASIC ORGANIZATION OF THE BRAIN The Cerebral Hemisphere Sulci- or grooves. Some sulci are used to divide Gyri- twisted ridges between the sulci in the brain tissue Fissures- deep sulci a) Median Longitudinal Fissure- separate the right and left cerebral hemisphere b) Transverse cerebral fissure- separates the cerebrum from the cerebellum Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Frontal lobe Parietal lobe Occipital lobe Temporal lobe LOBES OF THE BRAIN 5 MAJOR LOBES: Frontal lobe Parietal lobe Occipital lobe Temporal lobe Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Cerebral Lobes Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

SULCUS LANDMARK Some sulci are used to divide each cerebral hemisphere into 5 major lobes: Central sulcus- separates F from P a) Precentral gyrus b) Postcentral gyrus 2. Parieto-occipital sulcus- separates the P from O 3. Lateral sulcus- separates the T from F&P Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

White matter- composed of myelinated axons Gray matter- composed of neuronal cell bodies, dendrites and short unmyelinated axons. White matter- composed of myelinated axons Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Protection of the brain: 1) Dura Mater 2) Arachnoid 3) Pia MENINGES Protection of the brain: 1) Dura Mater 2) Arachnoid 3) Pia A B C Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

END NEXT: PNS