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11.1: Introduction • The central nervous system (CNS) consists of the brain and spinal cord. • The brainstem connects the brain to the spinal cord. • Communication to the peripheral nervous system (PNS) is by way of the spinal cord. 1 11.2: Meninges • The meninges • Membranes of CNS • Protect the CNS • Three (3) layers: • Dura mater • “Tough mother” • Venous sinuses • Arachnoid mater • “Spider mother” • Space contains cerebrospinal fluid (CSF) • Pia mater • “Little mother” • Encapsulates blood vessels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skin Scalp Subcutaneous tissue Cranium Bone of skull Cerebrum Dural sinus (superior sagittal sinus) Tentorium cerebelli Arachnoid granulation Dura mater Cerebellum Arachnoid mater Pia mater Vertebra Subarachnoid space Spinal cord Falx cerebri Meninges (a) Meninges Gray matter White matter (b) 2 Cerebrum Meninges of the Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Ventral root Dorsal root Spinal nerve Dorsal root ganglion Subarachnoid space Pia mater Arachnoid mater Epidural space Dura mater Dorsal root Dorsal branch (dorsal ramus) Spinal nerve Ventral branch (ventral ramus) Dorsal root ganglion Spinal cord Ventral root Epidural space Thoracic vertebra (a) (b) Body of vertebra 3 11.3: Ventricles and Cerebrospinal Fluid • There are four (4) ventricles • The ventricles are interconnected cavities within cerebral hemispheres and brain stem • The ventricles are continuous with the central canal of the spinal cord • They are filled with cerebrospinal fluid (CSF) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lateral ventricle Interventricular foramen Third ventricle Cerebral aqueduct Fourth ventricle To central canal of spinal cord • The four (4) ventricles are: • Lateral ventricles (2) • Known as the first and second ventricles • Third ventricle • Fourth ventricle • Interventricular foramen • Cerebral aqueduct (a) Interventricular foramen Lateral ventricle Third ventricle Cerebral aqueduct Fourth ventricle 4 (b) To central canal of spinal cord Cerebrospinal Fluid • Secreted by the choroid plexus • Circulates in ventricles, central canal of spinal cord, and the subarachnoid space • Completely surrounds the brain and spinal cord •Clear fluid similar to blood plasma • Volume is only about 120 ml. • Nutritive and protective • Helps maintain stable ion concentrations in the CNS Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Arachnoid granulations Blood-filled dural sinus Choroid plexuses of third ventricle Pia mater Third ventricle Cerebral aqueduct Fourth ventricle Subarachnoid space Arachnoid mater Dura mater Choroid plexus of fourth ventricle Central canal of spinal cord Pia mater Subarachnoid space Filum terminale Arachnoid mater Dura mater 5 11.4: Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Slender column of nervous tissue continuous with brain and brainstem • Extends downward through vertebral canal • Begins at foramen magnum and ends at L1/L2 interspace • Conduit for nerve impulses to and from brain and brainstem • Center for spinal reflexes Brainstem Foramen magnum Cervical enlargement Cervical enlargement Spinal cord Vertebral canal Lumbar enlargement Lumbar enlargement Conus medullaris Cauda equina Conus medullaris Filum terminale 6 (a) (b) Structure of the Spinal Cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior horn Posterior funiculus Posterior median sulcus White matter Gray matter Gray commissure Lateral funiculus Dorsal root of spinal nerve Central canal Anterior funiculus Dorsal root ganglion Ventral root Anterior of spinal nerve horn (a) Anterior median fissure Portion of spinal nerve 7 Reflex Arcs • Reflexes are automatic, subconscious responses to stimuli within or outside the body • Simple reflex arc (sensory – motor) • Most common reflex arc (sensory – association – motor) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sensory or afferent neuron Receptor Central Nervous System Motor or efferent neuron Effector (muscle or gland) 12 8 (a) Reflex Arcs 9 General Components of a Spinal Reflex Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinal cord Interneuron Dorsal 1 Receptor 3 2 Sensory neuron Cell body of sensory neuron White matter Gray matter 4 Ventral Motor neuron Central canal 5 Effector (muscle or gland) (b) 10 Reflex Behavior • Example is the knee-jerk reflex • Simple monosynaptic reflex • Helps maintain an upright posture Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Axon of sensory neuron Cell body of sensory neuron Spinal cord Cell body of motor neuron Axon of motor neuron Direction of impulse Effector (quadriceps femoris muscle group) Receptor associated with dendrites of sensory neuron Patella Patellar ligament 11 Reflex Behavior • Example is a withdrawal reflex • Prevents or limits tissue damage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell body of sensory neuron Axon of sensory neuron Direction of impulse Dendrite of sensory neuron Pain receptor in skin Tack Effector (flexor muscle contracts and withdraws part being stimulated) Interneuron Axon of motor neuron Spinal cord Cell body of motor neuron 12 11.5: Brain • Functions of the brain: • Major parts of the brain: • Interprets sensations • Cerebrum • Determines perception • Frontal lobes • Stores memory • Parietal lobes • Reasoning • Occipital lobes • Makes decisions • Temporal lobes • Coordinates muscular movements • Insula • Regulates visceral activities • Diencephalon • Determines personality • Cerebellum • Brainstem • Midbrain • Pons 13 • Medulla oblongata The Brain Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gyrus Skull Sulcus Meninges Cerebrum Corpus callosum Diencephalon Fornix Midbrain Brainstem Pons Cerebellum Medulla oblongata Spinal cord (a) Fornix Cerebrum Midbrain Pons Corpus callosum Transverse fissure Diencephalon Cerebellum Medulla oblongata Spinal cord 14 (b) b: © Martin M. Rotker/Photo Researchers, Inc. Structure of the Cerebrum • Corpus callosum • Connects cerebral hemispheres (a commissure) • Gyri • Bumps or convolutions • Sulci • Grooves in gray matter • Central sulcus of Rolando • Fissures • Longitudinal: separates the cerebral hemispheres • Transverse: separates cerebrum from cerebellum • Lateral fissure of Sylvius Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Parietal lobe Gyrus Sulcus Frontal lobe Lateral sulcus Occipital lobe Transverse fissure Cerebellar hemisphere Temporal lobe (a) Central sulcus Parietal lobe Central sulcus Longitudinal fissure Parietal lobe Occipital lobe (b) Occipital lobe Frontal lobe Insula Retracted temporal lobe (c) 15 Lobes of the Cerebrum • Five (5) lobes bilaterally: • Frontal lobe • Parietal lobe • Temporal lobe • Occipital lobe • Insula aka ‘Island of Reil’ (functions in interoceptive awareness & judging intensity of pain, among other things) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Parietal lobe Occipital lobe Frontal lobe Insula Retracted temporal lobe (c) 16 Functions of the Cerebrum • Interpreting impulses • Initiating voluntary movements • Storing information as memory • Retrieving stored information • Reasoning • Seat of intelligence and personality 17 Functional Regions of the Cerebral Cortex • Cerebral cortex • Thin layer of gray matter that constitutes the outermost portion of cerebrum • Contains 75% of all neurons in the nervous system Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Motor areas involved with the control of voluntary muscles Sensory areas involved with cutaneous and other senses Concentration, planning, problem solving Frontal eye field Parietal lobe Auditory area Sensory speech area ( Wernicke’s area) Front lobe Occipital lobe Motor speech area (Broca’s area) Combining visual images, visual recognition of objects Lateral sulcus Visual area Interpretation of auditory patterns Cerebellum 18 Temporal lobe Brainstem Functions of the Cerebral Lobes 19 Sensory Areas (post-central sulcus) • Cutaneous sensory area • Sensory area for taste • Near base of the central sulcus • Sensory area for smell • Parietal lobe • Interprets sensations on skin • Visual area • Occipital lobe • Interprets vision • Arises from centers deep within the cerebrum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Motor areas involved with the control of voluntary muscles Sensory areas involved with cutaneous and other senses Concentration, planning, problem solving Frontal eye field Parietal lobe Auditory area • Auditory area • Temporal lobe • Interprets hearing Sensory speech area ( Wernicke’s area) Front lobe Occipital lobe Motor speech area (Broca’s area) Combining visual images, visual recognition of objects Lateral sulcus Visual area Interpretation of auditory patterns Cerebellum Temporal lobe Brainstem 20 Motor & Sensory Areas Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Arm Forearm Trunk Trunk Pelvis Neck Forearm Arm Thigh Pelvis Thigh Thumb, fingers, and hand Leg Foot and toes Facial expression Hand, fingers, and thumb Upper face Leg Foot and toes Genitals Lips Salivation Vocalization Mastication Teeth and gums Swallowing Tongue and pharynx Longitudinal fissure (a) Motor area Longitudinal fissure (b) Sensory area Frontal lobe Motor area Sensory area Central sulcus Parietal lobe 21 Association Areas • Regions that are not primary motor or primary sensory areas • Widespread throughout the cerebral cortex • Analyze and interpret sensory experiences • Provide memory, reasoning, verbalization, judgment, emotions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central sulcus Motor areas involved with the control of voluntary muscles Sensory areas involved with cutaneous and other senses Concentration, planning, problem solving Frontal eye field Parietal lobe Auditory area Sensory speech area ( Wernicke’s area) Front lobe Occipital lobe Motor speech area (Broca’s area) Combining visual images, visual recognition of objects Lateral sulcus Visual area Interpretation of auditory patterns Cerebellum Temporal lobe Brainstem 22 Association Areas • Frontal lobe association areas • Concentrating • Planning • Complex problem solving • Parietal lobe association areas • Understanding speech • Choosing words to express thought • Temporal lobe association areas • Interpret complex sensory experiences • Store memories of visual scenes, music, and complex patterns • Occipital lobe association areas • Analyze and combine visual images with other sensory experiences 23 Hemisphere Dominance • The left hemisphere is dominant in most individuals • Dominant hemisphere controls: • Speech • Writing • Reading • Verbal skills • Analytical skills • Computational skills • Nondominant hemisphere controls: • Nonverbal tasks • Motor tasks • Understanding and interpreting musical and visual patterns • Provides emotional and intuitive thought processes 24 Memory • Short term memory • Long term memory • Working memory • Changes structure or • Closed neuronal circuit function of neurons • Circuit is stimulated over and • Enhances synaptic over transmission • When impulse flow ceases, memory does also unless it enters long-term memory via memory consolidation • Limited to 7 bits of information 25 Basal Nuclei • Masses of gray matter • Deep within cerebral hemispheres • Produce dopamine • Control certain muscular activities • Primarily by inhibiting motor functions Basal nuclei Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Longitudinal fissure Right cerebral hemisphere Caudate nucleus Putamen Globus pallidus Thalamus Cerebellum Hypothalamus Brainstem Spinal cord 26 Diencephalon • Between cerebral hemispheres and above the brainstem • Surrounds the third ventricle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Thalamus • Epithalamus • Hypothalamus • Optic tracts • Optic chiasm • Infundibulum • Posterior pituitary • Mammillary bodies • Pineal gland Superior colliculus Corpora quadrigemina Optic nerve Inferior colliculus Optic chiasma Pituitary gland Thalamus Mammillary body Third ventricle Optic tract Pons Cerebral peduncles Pineal gland Fourth ventricle Pyramidal tract Olive Cerebellar peduncles Medulla oblongata Spinal cord (a) (b) 27 Diencephalon • Thalamus • Gateway for sensory impulses heading to cerebral cortex • Receives all sensory impulses (except smell) • Channels impulses to appropriate part of cerebral cortex for interpretation • Epithalamus • Functions to connect the limbic system to other parts of the brain. •Hypothalamus • Maintains homeostasis by regulating visceral activities • Links nervous and endocrine systems (hence some say the neuroendocrine system) 28 Diencephalon The Limbic System • Consists of: • Portions of frontal lobe • Portions of temporal lobe • Hypothalamus • Thalamus • Basal nuclei • Other deep nuclei • Functions: • Controls emotions • Produces feelings • Interprets sensory impulses 29 Brainstem Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hypothalamus Diencephalon Three parts: 1. Midbrain 2. Pons 3. Medulla Oblongata Thalamus Corpus callosum Corpora quadrigemina Midbrain Cerebral aqueduct Pons Reticular formation Medulla oblongata Spinal cord 30 Midbrain Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior colliculus Corpora quadrigemina Optic nerve Inferior colliculus Optic chiasma Pituitary gland Thalamus Mammillary body Third ventricle Optic tract • Between diencephalon and pons • Contains bundles of fibers that join lower parts of brainstem and spinal cord with higher parts of the brain • Cerebral aqueduct • Cerebral peduncles (bundles of nerve fibers) • Corpora quadrigemina (centers for visual and auditory reflexes) Pons Cerebral peduncles Pineal gland Fourth ventricle Pyramidal tract Olive Cerebellar peduncles Medulla oblongata Spinal cord (a) (b) 31 Pons • Rounded bulge on underside of brainstem • Between medulla oblongata and midbrain • Helps regulate rate and depth of breathing • Relays nerve impulses to and from medulla oblongata and cerebellum (bridge) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior colliculus Corpora quadrigemina Optic nerve Inferior colliculus Optic chiasma Pituitary gland Thalamus Mammillary body Third ventricle Optic tract Pons Cerebral peduncles Pineal gland Fourth ventricle Pyramidal tract Olive Cerebellar peduncles Medulla oblongata Spinal cord (a) (b) 32 Medulla Oblongata • Enlarged continuation of spinal cord • Conducts ascending and descending impulses between brain and spinal cord • Contains cardiac, vasomotor, and respiratory control centers • Contains various nonvital reflex control centers (coughing, sneezing, swallowing, and vomiting) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior colliculus Corpora quadrigemina Optic nerve Inferior colliculus Optic chiasma Pituitary gland Thalamus Mammillary body Third ventricle Optic tract Pons Cerebral peduncles Pineal gland Fourth ventricle Pyramidal tract Olive Cerebellar peduncles Medulla oblongata Spinal cord (a) (b) 33 Cerebellum • Inferior to occipital lobes Longitudinal • Posterior to pons and medulla fissure oblongata • Two hemispheres like cerebrum Thalamus • Vermis connects hemispheres • Cerebellar cortex (gray matter) Superior peduncle • Arbor vitae (white matter) Pons Middle peduncle • Cerebellar peduncles (nerve fiber Inferior peduncle Medulla oblongata tracts) • Dentate nucleus (largest nucleus in cerebellum) • Integrates sensory information concerning position of body parts • Coordinates skeletal muscle activity • Maintains posture Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Corpus callosum Cerebellum 34 Major Parts of the Brain 35 11.6: Peripheral Nervous System • Cranial nerves arising from the brain • Somatic fibers connecting to the skin and skeletal muscles • Autonomic fibers connecting to viscera • Spinal nerves arising from the spinal cord • Somatic fibers connecting to the skin and skeletal muscles • Autonomic fibers connecting to viscera 36 Nervous System Subdivisions 37 Structure of a Peripheral Nerve Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fascicle Peripheral nerve Epineurium Motor neuron ending Axon Perineurium Endoneurium Node of Ranvier Schwann cell Sensory receptor Myelin sheath Neurilemma 38 Nerve and Nerve Fiber Classification • Sensory nerves • Conduct impulses into brain or spinal cord • Motor nerves • Conduct impulses to muscles or glands • Mixed (both sensory and motor) nerves • Contain both sensory nerve fibers and motor nerve fibers • Most nerves are mixed nerves • ALL spinal nerves are mixed nerves (except the first pair) 39 Cranial Nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olfactory bulb Olfactory (I) Olfactory tract Optic (II) Optic tract Oculomotor (III) Trochlear (IV) Trigeminal (V) Vestibulocochlear (VIII) Abducens (VI) Hypoglossal (XII) Facial (VII) Vagus (X) Glossopharyngeal (IX) Accessory (XI) 40 Cranial Nerves I and II • Olfactory nerve (CN I) • Sensory nerve • Fibers transmit impulses associated with smell • Optic nerve (CN II) • Sensory nerve • Fibers transmit impulses associated with vision 41 Cranial Nerves III and IV • Oculomotor nerve (CN III) • Primarily motor nerve • Motor impulses to muscles that: • Raise eyelids • Move the eyes • Focus lens • Adjust light entering eye • Trochlear nerve (CN IV) • Primarily motor nerve • Motor impulses to muscles that move the eyes • Some sensory • Proprioceptors • Some sensory • Proprioceptors 42 Cranial Nerve V Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Trigeminal nerve (CN V) • Mixed nerve • “Three (3) sisters” • (1) Ophthalmic division • Sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids Lacrimal nerve Ophthalmic division Eye Maxillary division • (3) Mandibular division • Sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip • Motor to muscles of mastication and muscles in floor of mouth Infraorbital nerve Mandibular division • (2) Maxillary division • Sensory from upper teeth, upper gum, upper lip, palate, and skin of face Lacrimal gland Maxilla Lingual nerve Inferior alveolar nerve Tongue Mental nerve 43 Mandible Cranial Nerves VI and VII • Abducens nerve (CN VI) • Primarily motor nerve • Motor impulses to muscles that move the eyes • Some sensory •Proprioceptors • Facial nerve (CN VII) • Mixed nerve • Sensory from taste receptors • Motor to muscles of facial expression, tear glands, and salivary glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Temporal nerve Zygomatic nerve Buccal nerve Facial nerve Posterior auricular nerve Parotid salivary gland Mandibular nerve Cervical nerve 44 68 Cranial Nerves VIII and IX • Vestibulocochlear nerve (CN VIII) • Aka acoustic or auditory nerve • Sensory nerve • Two (2) branches: • Vestibular branch • Sensory from equilibrium receptors of ear • Cochlear branch • Sensory from hearing receptors • Glossopharyngeal nerve (CN IX) • Mixed nerve • Sensory from pharynx, tonsils, tongue and carotid arteries • Motor to salivary glands and muscles of pharynx 45 Cranial Nerve X Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Vagus nerve (CN X) • Mixed nerve • Somatic motor to muscles of speech and swallowing • Autonomic motor to viscera of thorax and abdomen • Sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen Meningeal branch Auricular branch Pharyngeal branch Superior ganglion of vagus nerve Inferior ganglion of vagus nerve Palate Nerve XI Superior laryngeal nerve Nerve XII Carotid body Recurrent laryngeal nerve Left vagus nerve Cardiac nerves Lung Heart Stomach Liver Spleen Pancreas Kidney Small intestine 46 Large intestine Cranial Nerves XI and XII • Accessory nerve (CN XI) • Primarily motor nerve • We called this “Spinal” Accessory because: • Cranial branch • Motor to muscles of soft palate, pharynx and larynx • Spinal branch • Motor to muscles of neck and back • Some sensory • Proprioceptor • Hypoglossal nerve (CN XII) • Primarily motor • Motor to muscles of the tongue • Some sensory • Proprioceptor 47 Functions of Cranial Nerves 48 Spinal Nerves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • ALL are mixed nerves (except the first pair) • 31 pairs of spinal nerves: • 8 cervical nerves • (C1 to C8) • 12 thoracic nerves • (T1 to T12) • 5 lumbar nerves • (L1 to L5) • 5 sacral nerves • (S1 to S5) • 1 coccygeal nerve • (Co or Cc) C1 C2 C3 C4 C5 C6 C7 C8 T1 T2 Posterior view Cervical nerves T3 T4 T5 T6 T7 Thoracic nerves T8 T9 T10 T11 T12 L1 Cauda equina L2 L3 L4 Lumbar nerves L5 S1 S2 S3 S4 S5 Co Sacral nerves Coccygeal nerve 49 Spinal Nerves • Dorsal root (aka posterior root) • Sensory root • Axons of sensory neurons are in the dorsal root ganglion • Dorsal root ganglion • Aka DRG • Cell bodies of sensory neurons whose axons conduct impulses inward from peripheral body parts Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dorsal root Dorsal root ganglion Dorsal root Dorsal branch of spinal nerve Ventral branch of spinal nerve Ventral root Paravertebral ganglion Posterior median sulcus Posterior horn Visceral branch of spinal nerve (b) Lateral horn Ventral branch of spinal nerve (ventral ramus) Anterior horn Central canal Dorsal branch of spinal nerve (dorsal ramus) Anterior median fissure Paravertebral ganglion (a) Ventral root Spinal nerve Visceral branch of spinal nerve 50 Spinal Nerves • Ventral root (aka anterior root) • Motor root • Axons of motor neurons whose cell bodies are in the spinal cord Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dorsal root Dorsal root ganglion Dorsal root Dorsal branch of spinal nerve Ventral branch of spinal nerve Ventral root Paravertebral ganglion Posterior median sulcus Posterior horn • Spinal nerve • Union of ventral root and dorsal roots • Hence we now have a “mixed” nerve Visceral branch of spinal nerve (b) Lateral horn Ventral branch of spinal nerve (ventral ramus) Anterior horn Central canal Dorsal branch of spinal nerve (dorsal ramus) Anterior median fissure Paravertebral ganglion (a) Ventral root Spinal nerve Visceral branch of spinal nerve 51 Nerve Plexuses • Nerve plexus • Complex networks formed by anterior branches of spinal nerves • The fibers of various spinal nerves are sorted and recombined • There are three (3) nerve plexuses: • (1) Cervical plexus – Lies deep within the neck • (2) Brachial plexus – Lies deep within shoulders • (3) Lumbosacral plexus – Extends from lumbar region into pelvic cavity 52 Plexuses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior view Musculocutaneous nerve Axillary nerve Radial nerve Median nerve Ulnar nerve Phrenic nerve C1 C2 C3 C4 C5 C6 C7 C8 T1 Cervical plexus (C1–C4) Brachial plexus (C5–T1) T2 T3 T4 T5 T6 T7 Intercostal nerves T8 T9 T10 T11 T12 Cauda equina L1 L2 L3 L4 Femoral nerve L5 S1 S2 S3 S4 S5 Obturator nerve Lumbosacral plexus (T12–S5) Co Sciatic nerve 53 11.7: Autonomic Nervous System • Functions without conscious effort • Controls visceral activities • Regulates smooth muscle, cardiac muscle, and glands • Efferent fibers typically lead to ganglia outside of the CNS • Two autonomic divisions regulate: • Sympathetic division (speeds up) • Prepares body for ‘fight or flight’ situations • Parasympathetic division (pauses or slows down) • Prepares body for ‘resting and digesting’ activities 54 Sympathetic Division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lacrimal gland Eye Parotid gland, submandibular and sublingual glands Blood vessels Heart Celiac and pulmonary plexuses Trachea Lungs Skin Celiac ganglion Fibers to skin, blood vessels, and adipose tissue Liver Gallbladder Superior mesenteric ganglion Stomach Pancreas Small intestine Large intestine Spinal cord Inferior mesenteric ganglion Adrenal gland Kidney Sympathetic chain ganglia Urinary bladder Preganglionic Postganglionic neuron neuron Ovary Penis Uterus Scrotum 55 Parasympathetic Division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sphenopalatine ganglion Lacrimal gland Ciliary ganglion Cranial nerve III Submandibular and sublingual glands Submandibular ganglion Cranial nerve VII Eye Parotid gland Otic ganglion Cranial nerve IX Heart Cranial nerve X (Vagus) Trachea Lung Cardiac and pulmonary plexuses Liver Gallbladder Stomach Celiac plexus Spleen Pancreas Superior hypogastric plexus Spinal cord Small intestine Large intestine Inferior hypogastric plexus Kidney Pelvic nerves Urinary bladder Preganglionic Postganglionic neuron neuron Scrotum Uterus Penis Ovary 56 Control of Autonomic Activity • Controlled largely by CNS • Medulla oblongata regulates cardiac, vasomotor and respiratory activities • Hypothalamus regulates visceral functions, such as body temperature, hunger, thirst, and water and electrolyte balance • Limbic system and cerebral cortex control emotional responses 57