The Nervous System

Central nervous system (CNS) Peripheral nervous system (PNS) Brain and spinal cord Cranial nerves and spinal nerves Integrative and control centers Communication lines between the CNS and the rest of the body Sensory (afferent) division Motor (efferent) division Somatic and visceral sensory nerve fibers Motor nerve fibers Conducts impulses from the CNS to effectors (muscles and glands) Conducts impulses from receptors to the CNS Somatic sensory fiber Somatic nervous System (SNS) Autonomic nervous system (ANS) Skin Somatic motor (voluntary) Visceral motor (involuntary) Conducts impulses from the CNS to skeletal muscles Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands Visceral sensory fiber Stomach Skeletal muscle Motor fiber of somatic nervous system Sympathetic division Parasympathetic division Mobilizes body systems during activity; “fight or flight” Conserves energy Promotes house- keeping functions during rest Sympathetic motor fiber of ANS Heart Structure Function Sensory (afferent) division of PNS Parasympathetic motor fiber of ANS Bladder Motor (efferent) division of PNS

Astrocytes Capillary Neuron Astrocyte

Microglia Neuron Microglial cell

Ependymal Cells Fluid-filled cavity Ependymal cells Brain or spinal cord tissue

Oligodendrocytes Myelin sheath Process of oligodendrocyte Nerve fibers

Satellite Cells and Schwann Cells Cell body of neuron Schwann cells (forming myelin sheath) Nerve fiber

and conducting region) Dendrites (receptive regions) Cell body (biosynthetic center and receptive region) Nucleolus Axon (impulse generating and conducting region) Impulse direction Nucleus Node of Ranvier Nissl bodies Axon terminals (secretory region) Axon hillock Schwann cell (one inter- node) Neurilemma Terminal branches

Table 11.1 (1 of 3)

Generation of an Action Potential The big picture 1 Resting state 2 Depolarization 3 Repolarization 3 4 Hyperpolarization 2 Action potential Membrane potential (mV) Threshold 1 1 4 Time (ms) Refractory Period

Neural Pools

Neural Pools

Neural Pools

The Brain and Spinal Cord

Meninges Skin of scalp Periosteum Bone of skull Periosteal Meningeal Dura Mater Superior sagittal sinus Arachnoid Mater Pia Mater Subdural space Arachnoid villus Blood vessel Subarachnoid space Falx cerebri (in longitudinal fissure only)

Spinal Cord Cervical spinal nerves Cervical enlargement Dura and arachnoid mater The spinal cord and its nerve roots, with the bony vertebral arches removed. The dura mater and arachnoid mater are cut open and reflected laterally. Thoracic spinal nerves Lumbar enlargement Conus medullaris Lumbar spinal nerves Cauda equina Filum terminale Sacral spinal nerves

The Major Regions of the Brain Cerebral hemisphere Diencephalon Cerebellum Brain stem • Midbrain • Pons • Medulla oblongata

Ventricles of the Brain Lateral ventricle Septum pellucidum Anterior horn Posterior horn Inferior horn Interventricular foramen Lateral aperture Median aperture Third ventricle Inferior horn Lateral aperture Cerebral aqueduct Fourth ventricle Central canal Anterior view Left lateral view

Cerebral Hemispheres Precentral gyrus Central sulcus Postcentral gyrus Frontal lobe Parietal lobe Parieto-occipital sulcus (on medial surface of hemisphere) Lateral sulcus Occipital lobe Temporal lobe Transverse cerebral fissure Cerebellum Pons Medulla oblongata Fissure Spinal cord (a deep sulcus) Gyrus Cortex (gray matter) Sulcus White matter

Cerebral Hemispheres Central sulcus Frontal lobe Gyri of insula Temporal lobe (pulled down)

Cerebral Hemispheres Anterior Longitudinal Frontal lobe fissure Cerebral veins and arteries covered by arachnoid mater Parietal lobe Left cerebral hemisphere Right cerebral hemisphere Occipital lobe Posterior

Functional Areas of the Cerebral Cortex Motor areas Central sulcus Sensory areas and related association areas Primary motor cortex Primary somatosensory cortex Premotor cortex Somatic sensation Frontal eye field Somatosensory association cortex Broca’s area (outlined by dashes) Gustatory cortex (in insula) Taste Prefrontal cortex Working memory for spatial tasks Wernicke’s area (outlined by dashes) Executive area for task management Working memory for object-recall tasks Primary visual cortex Visual association area Vision Solving complex, multitask problems Auditory association area Hearing Primary auditory cortex (a) Lateral view, left cerebral hemisphere Primary motor cortex Motor association cortex Primary sensory cortex Sensory association cortex Multimodal association cortex

Hemispheric Lateralization Cingulate gyrus Primary motor cortex Premotor cortex Central sulcus Corpus callosum Primary somatosensory cortex Frontal eye field Parietal lobe Somatosensory association cortex Prefrontal cortex Parieto-occipital sulcus Occipital lobe Processes emotions related to personal and social interactions Visual association area Orbitofrontal cortex Olfactory bulb Olfactory tract Primary visual cortex Fornix Temporal lobe Uncus Calcarine sulcus Primary olfactory cortex Parahippocampal gyrus (b) Parasagittal view, right hemisphere Primary motor cortex Motor association cortex Primary sensory cortex Sensory association cortex Multimodal association cortex

Diencephalon Cerebral hemisphere Septum pellucidum Corpus callosum Interthalamic adhesion (intermediate mass of thalamus) Fornix Choroid plexus Thalamus (encloses third ventricle) Interven- tricular foramen Posterior commissure Pineal gland (part of epithalamus) Anterior commissure Corpora quadrigemina Mid- brain Hypothalamus Cerebral aqueduct Optic chiasma Arbor vitae (of cerebellum) Pituitary gland Fourth ventricle Mammillary body Choroid plexus Pons Cerebellum Medulla oblongata Spinal cord Figure 12.12

Brain Stem Frontal lobe Olfactory bulb (synapse point of cranial nerve I) Optic chiasma Optic nerve (II) Optic tract Mammillary body Midbrain Pons Temporal lobe Medulla oblongata Cerebellum Spinal cord

Brain Stem Optic chiasma Optic nerve (II) Diencephalon Crus cerebri of View (a) Optic chiasma Optic nerve (II) Diencephalon Crus cerebri of cerebral peduncles (midbrain) • Thalamus • Hypothalamus Thalamus Mammillary body Diencephalon Hypothalamus Oculomotor nerve (III) Midbrain Pons Brainstem Trochlear nerve (IV) Medulla oblongata Trigeminal nerve (V) Middle cerebellar peduncle Pons Facial nerve (VII) Abducens nerve (VI) Vestibulocochlear nerve (VIII) Glossopharyngeal nerve (IX) Hypoglossal nerve (XII) Pyramid Vagus nerve (X) Ventral root of first cervical nerve Accessory nerve (XI) Decussation of pyramids Spinal cord Ventral view

Brain Stem Thalamus Diencephalon Midbrain • Superior colliculus View (c) Diencephalon Midbrain • Superior colliculus Corpora quadrigemina of tectum • Inferior colliculus • Trochlear nerve (IV) Pineal gland • Superior cerebellar peduncle Pons • Middle cerebellar peduncle Medulla oblongata Anterior wall of fourth ventricle • Inferior cerebellar peduncle • Facial nerve (VII) • Vestibulocochlear nerve (VIII) Choroid plexus (fourth ventricle) • Glossopharyngeal nerve (IX) • Vagus nerve (X) • Accessory nerve (XI) Dorsal median sulcus Thalamus Dorsal root of first cervical nerve Diencephalon Hypothalamus Midbrain Pons Brainstem Dorsal view Medulla oblongata