Chapter 3: Structure of the Nervous System (Neuroanatomy) PDF

Chapter 3 Structure of the Nervous System (Neuroanatomy)  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structure of Central Nervous System – Forebrain – Midbrain – Hindbrain 4. Structure of Peripheral Nervous System – Spinal Nerves...

Chapter 3 Structure of the Nervous System (Neuroanatomy)  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structure of Central Nervous System – Forebrain – Midbrain – Hindbrain 4. Structure of Peripheral Nervous System – Spinal Nerves – Autonomic Nervous System  Recall... Two basic divisions: – Central Nervous System (CNS) Brain and spinal cord – Peripheral Nervous System (PNS) Outside the brain and spinal cord CNS communicates to rest of body via nerves…  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain 4. Structures of Peripheral Nervous System – Spinal Nerves – Autonomic Nervous System  Anatomical Directions Neuraxis Directions are normally described relative to the neuraxis, which goes from the bottom of the spinal cord to the front of the forebrain  Anatomical Directions Neuraxis Toward back Toward head Toward tail Toward belly  Anatomical Directions Rostral or anterior Neuraxis Caudal or posterior – In humans, Ventral neuraxis rotates 900 at the head  Anatomical Directions Neuraxis Dorsal – In humans, Anterior Posterior neuraxis rotates 900 Ventral Anterio at the head r Dorsal Ventra l Poster ior  Anatomical Directions Neuraxis Medial: toward midline Lateral: toward side Ipsilateral (same side) Contralateral (opposite side)  Anatomical Directions Neuraxis Medial: toward midline Lateral: toward side Ipsilateral (same side) Contralateral (opposite side)  Anatomical Directions Planes of View Coronal (cross) Section – View from front Sagittal Section – View from side Horizontal Section – View from top  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain 4. Structures of Peripheral Nervous System – Spinal Nerves – Autonomic Nervous System  The Meninges and Ventricular System Meninges – Protective layers of tissues surrounding the brain and spinal cord – Dura mater is the outer layer (hard mother) – Arachnoid is the middle layer (spider-web) – Pia mater is closest to brain (delicate mother)  The Meninges and Ventricular System Meninges Subarachnoid space: area between arachnoid and pia mater. - filled with cerebrospinal fluid (CSF) - brain “floats” in CSF  The Meninges and Ventricular System Ventricular System A series of fluid filled interconnected chambers (ventricles) within brain Lateral ventricles: one on each side of brain (numbered I and II) Third ventricle: in middle of brain near hypothalamus Fourth Ventricles: In hindbrain (between cerebellum and pons)  The Meninges and Ventricular System Ventricular System Side View  The Meninges and Ventricular System Ventricular System Front View Top View  The Meninges and Ventricular System Ventricular System CSF is produced continuously by cells (choroid plexus) in ventricles Flows between ventricles via aqueducts and down into spinal canal Also flows out into subarachnoid space surrounding brain As pressure increases, CSF reabsorbed into veins and general blood circulation Carries waste by-products from brain (e.g., neurotransmitter metabolites)  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain 4. Structures of Peripheral Nervous System – Spinal Nerves – Autonomic Nervous System Structures of the Central Nervous System Divisions of the Brain Major Subdivision Example Structures Division Forebrain Telencephalon Cerebral Cortex Basal Ganglia Limbic System Diencephalon Thalamus Hypothalamus Midbrain Mesencephalon Tectum Tegmentum Hindbrain Metencephalon Cerebellum Pons Myelencephalon Medulla oblongata Structures of the Central Nervous System Divisions of the Brain  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System Structures of the Central Nervous System Forebrain: Most anterior division of the brain (most recent). Telencephalon - two cerebral hemispheres (corpus callosum); four lobes - subcortical structures: cingulate gyrus, limbic system, basal ganglia Diencephalon - Pineal gland (epithalamus) - Thalamus - Hypothalamus Structures of the Central Nervous System Telencephalon: Cerebral Cortex Most recent tissue Convoluted - Fissure (sulcus): indentation (groove) in cortex - Gyrus: bump or protrusion in cortex Cross section varies in appearance - Gray matter: areas of cell bodies of neurons - White matter: Areas of myelinated axons (tracts) Structures of the Central Nervous System Four Lobes of Cerebral Cortex 1.Frontal lobe 2.Temporal Lobe 3.Parietal lobe 4.Occipital lobe Structures of the Central Nervous System Four Lobes of Cerebral Cortex 1. Frontal lobe - primary motor cortex controls voluntary movement - premotor cortex (motor association cortex) planning of movement - prefrontal cortex (executive function attention, short term memory) - language production - regulates emotion - olfaction  Structures of the Central Nervous System Four Lobes of Cerebral Cortex 2. Temporal lobe - primary auditory cortex - auditory association cortex - visual association cortex (forms) 3. Parietal lobe - primary somatosensory cortex receives touch related information from the body - somatosensory association cortex - vision (movement) 4. Occipital lobe - primary visual cortex  Structures of the Central Nervous System Four Lobes of Cerebral Cortex Midsagittal View Ventral View Structures of the Central Nervous System Four Lobes of Cerebral Cortex 1.Frontal lobe 2.Temporal Lobe 3.Parietal lobe 4.Occipital lobe Structures of the Central Nervous System Primary Motor and Sensory Cortex Structures of the Central Nervous System Lateralization in the Cerebral Cortex Some functions of cerebral hemispheres are lateralized—located primarily on one side of the brain - Left hemisphere analyzes information (serial) - Right hemisphere synthesizes information (holistic) Corpus callosum connects corresponding parts of cerebral cortex of left and right hemispheres Structures of the Central Nervous System Telencephalon: Limbic System – Ring of structures including the hippocampus and the amygdala – Involved in learning, memory, and emotions Structures of the Central Nervous System Telencephalon: Basal Ganglia - Group of subcortical nuclei in the forebrain - Involved in the control of movement  Structures of the Central Nervous System Diencephalon: Second major division of the forebrain Thalamus – Projects sensory information to specific regions of cerebral cortex and receives information from it Hypothalamus – Controls autonomic nervous system and endocrine system – Regulate behaviors related to basic survival (eating, drinking, sex/bonding, thermoregulation) – Controls pituitary gland (regulation of hormones)  Structures of the Central Nervous System Pituitary Gland  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Central Nervous System Midbrain: Mesencephalon tectum Tectum – “roof” – Superior colliculus (vision) – Inferior colliculus (hearing) Tegmentum – Floor Midbrain – Substantia nigra – Ventral Tegmental Area – Red nucleus tegmentum – Periaqueductal gray matter – Some reticular formation  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Central Nervous System Hindrain: Metencephalon Cerebellum – Receives visual, auditory, vestibular, and somatosensory information and information about individual muscle movements – Modifies motor outflow, exerting a coordinating and smoothing effect on movements Pons – large bulge in the brain stem – relays information from the cerebral cortex to the cerebellum – Contains reticular formation  Structures of the Central Nervous System Hindrain: Metencephalon - Pons and Cerebellum  Structures of the Central Nervous System Hindrain: Myelencephalon - Medulla Obongata - Contains nuclei of cranial nerves (e.g. vagus nerve) which regulate vital functions (breathing and heart rate)  Structures of the Central Nervous System Hindrain: Myelencephalon - Medulla Obongata - Contains nuclei of cranial nerves (e.g. vagus nerve) which regulate vital functions (breathing and heart rate)  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Central Nervous System Spinal Cord - long, tubelike structure runs through spinal column - subdivided (e.g., cervical, thoracic, lumbar, sacral, coccyx) - spinal canal in centre (CSF) and surrounded by meninges (CSF) - White Matter: descending motor tracts to muscles and ascending somatosensory tracts to brain - Gray Matter: somas and interneurons  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Peripheral Nervous System Spinal Nerves - One pair (left-right) for each vertebrae - Dorsal root (sensory information) - Ventral Root (motor) Spinal Cord & Nerves  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Peripheral Nervous System Cranial Nerves – twelve pairs – attached to the ventral surface of the brain – Most serve sensory and motor functions of the head and neck region – The vagus nerve regulates the functions of organs in the thoracic and abdominal cavities  Topics 1. Anatomical Directions 2. The Meninges and Ventricular System 3. Structures of Central Nervous System – Forebrain – Midbrain – Hindbrain – Spinal Cord 4. Structures of Peripheral Nervous System – Spinal Nerves – Cranial Nerves – Autonomic Nervous System  Structures of the Peripheral Nervous System Autonomic Nervous System - Functional branch of PNS - concerned with regulation of organs of body - Consists of two anatomically separate systems: sympathetic division and parasympathetic division  Structures of the Peripheral Nervous System Autonomic Nervous System