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PowerPoint Lecture Outlines to accompany
Hole’s HumanAnatomy and Physiology
Eleventh EditionModified by Mrs. Fiser
Shier Butler Lewis
Chapter
11
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Warm Up
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CentralCanal
WhiteMatter
Grey Matter
Inter-Neuron
Impulse
Receptor
SensoryNeuron
Effector ( muscle or gland)
MotorNeuronCell Body ofSensoryNeuron
http://www.youtube.com/watch?v=GbxGB8Dkd3Q
The snake
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Chapter 11Nervous System II
Meninges• membranes surrounding CNS• protect CNS• three layers
• dura mater – outer, tough• arachnoid mater – thin, weblike• pia mater – inner, very thin
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Meninges of the Spinal Cord
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Ventricles
• interconnected cavities• within cerebral hemispheres and brain stem• continuous with central canal of spinal cord• filled with cerebrospinal fluid (CSF)
• lateral ventricles• third ventricle• fourth ventricle• cerebral aqueduct
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Cerebrospinal Fluid
• secreted by choroid plexus• circulates in ventricles, central canal of spinal cord, and subarachnoid space• completely surrounds brain and spinal cord• clear liquid• nutritive and protective• helps maintain stable ion concentrations in CNS
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Spinal Cord
• slender column of nervous tissue continuous with brain• extends downward through vertebral canal• begins at level of foramen magnum and terminates near first and second lumbar
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Cross Section of Spinal Cord
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Functions of Spinal Cord
• center for spinal reflexes
• conduit for nerve impulses to and from the brain
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Reflex Arcs
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General Components of a Spinal Reflex
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Reflex Behavior
• example is the knee-jerk reflex• simple monosynaptic reflex• helps maintain an upright posture
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Reflex Behavior• example is a withdrawal reflex• prevents or limits tissue damage
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Reflex Arc
• example crossed extensor reflex• crossing of sensory impulses within the reflex centerto produce an opposite effect
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Tracts of the Spinal Cord
• Ascending tracts conduct sensory impulses to the brain• Descending tracts conduct motor impulses from the brain to motor neurons reaching muscles and glands
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Ascending Tracts
• major ascending spinal cord tracts
• fasciculus gracilis and fasciculus cuneatus• spinothalamic
• lateral and anterior• spinocerebellar
• posterior and anterior
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Descending Tracts
• major descending spinal cord tracts
• corticospinal• lateral and anterior
• reticulospinal• lateral, anterior and medial
• rubrospinal
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Nerve Tracts of the Spinal Cord
Animations/video clips• Patellar reflex
http://www.youtube.com/watch?v=qpw31bvoLpg&feature=related
http://www.edumedia-sciences.com/en/a496-patellar-reflex
Biceps Reflex & Triceps Reflexhttp://www.youtube.com/watch?
v=2sm4ynlzEi8&safety_mode=true&persist_safety_mode=1&safe=active
Achilles Reflex
http://www.youtube.com/watch?v=BEQ6BbLLucA&NR=1
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Relfex arcs animations
• http://www.sumanasinc.com/webcontent/animations/content/reflexarcs.html
• http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf
Checking knee reflexes
• http://www.youtube.com/watch?v=QmNQdLkkJHM&feature=related
• http://www.neuroexam.com/content.php?p=31
Warm up (p 236 for help)
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910 (name it)11
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Test questions 31-50: Label
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Brain
Functions• interprets sensations• determines perception• stores memory• reasoning• makes decisions• coordinates muscular movements• regulates visceral activities• determines personality
Major Parts• cerebrum
• two hemispheres• diencephalon• brainstem• cerebellum
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Brain
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Structure of Cerebrum
• corpus callosum• connects cerebral hemispheres
• convolutions • bumps or gyri
• sulci• grooves
• longitudinal fissure• separates hemispheres
• transverse fissure• separates cerebrum from cerebellum
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Lobes of Cerebral Hemispheres
• Frontal• Parietal• Temporal• Occipital• Insula
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Functions of the Cerebrum
• interpreting impulses• initiating voluntary movements• storing information as memory• retrieving stored information • reasoning• seat of intelligence and personality
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Functional Regions of Cerebral Cortex
Cerebral Cortex – thin layer of gray matter that constitutes the outermost portion of cerebrum; contains 75% of all neurons in nervous system
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Sensory Areas
• Cutaneous Sensory Area
• parietal lobe• interprets sensations on skin
• Visual Area• occipital lobe• interprets vision
• Auditory Area• temporal lobe• interprets hearing
• Sensory Area for Taste• near bases of the central sulcus
• Sensory Area for Smell
• arise from centers deep within the cerebrum
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Sensory Areas
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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
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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
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Motor Areas
• Primary Motor Areas• frontal lobes• control voluntary muscles
• Broca’s Area• anterior to primary motor cortex• usually in left hemisphere• controls muscles needed for speech
• Frontal Eye Field• above Broca’s area• controls voluntary movements of eyes and eyelids
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Motor Areas
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Functions of the Cerebral Lobes
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Basal Nuclei
• masses of gray matter• deep within cerebral hemispheres• caudate nucleus, putamen, globus pallidus• produce dopamine• control certain muscular activities
• primarily by inhibiting motor functions
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Diencephalon
• between cerebral hemispheres and above the brainstem• surrounds third ventricle
• thalamus• hypothalamus• optic tracts• optic chiasma• infundibulum• posterior pituitary• mammillary bodies• pineal gland
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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
Hypothalamus• maintains homeostasis by regulating visceral activities • links nervous and endocrine systems
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Diencephalon
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
Limbic System
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Brain Stem
Three Parts1. Midbrain2. Pons3. Medulla Oblongata
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Midbrain
• between diencephalon and pons• contains bundles of fibers that join lower parts of brainstem and spinal cord with higher part of brain• cerebral aqueduct• cerebral peduncles – bundles of nerve fibers• corpora quadrigemina – centers for visual and auditory reflexes
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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
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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, vomiting)
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Reticular Formation
• complex network of nerve fibers scattered throughout the brain stem• extends into the diencephalon• connects to centers of hypothalamus, basal nuclei, cerebellum, and cerebrum• filters incoming sensory information • arouses cerebral cortex into state of wakefulness
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Cerebellum
• inferior to occipital lobes• posterior to pons and medulla oblongata• two hemispheres• vermis connects hemispheres• cerebellar cortex – gray matter• arbor vitae – white matter• cerebellar peduncles – nerve fiber tracts• dentate nucleus – largest nucleus in cerebellum• integrates sensory information concerning position of body parts• coordinates skeletal muscle activity• maintains posture
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Major Parts of the Brain
Warm up- Name cranial nerves and structures and list the function of each cranial nerve on the back of
paper.
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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
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Nervous System Subdivisions
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Structure of a Peripheral Nerve
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Nerve Fiber Classification
• Sensory Nerves – conduct impulses into brain or spinal cord
• Motor Nerves – conduct impulses to muscles or glands
• Mixed Nerves – contain both sensory nerve fibers and motor nerve fibers; most nerves
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Nerve Fiber Classification
General somatic efferent fibers• carry motor impulses from CNS to skeletal muscles
General visceral efferent fibers• carry motor impulses away from CNS to smooth muscles and glands
General somatic afferent fibers• carry sensory impulses to CNS from skin and skeletal muscles
General visceral afferent fibers• carry sensory impulses to CNS from blood vessels and internal organs
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Nerve Fiber Classification
Special somatic efferent fibers• carry motor impulses from brain to muscles used in chewing, swallowing, speaking, and forming facial expressions
Special visceral afferent fibers• carry sensory impulses to brain from olfactory and taste receptors
Special somatic afferent fibers• carry sensory impulses to brain from receptors of sight, hearing, and equilibrium
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Cranial Nerves
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Cranial Nerves I and II
Olfactory (I)• sensory• fibers transmit impulses associated with smell
Optic (II)• sensory• fibers transmit impulses associated with vision
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Cranial Nerves III and IV
Trochlear (IV)• some sensory
• proprioreceptors• primarily motor• motor impulses to muscles that move the eyes
Oculomotor (III)• some sensory
• proprioreceptors • primarily motor• motor impulses to muscles that
• raise eyelids• move the eyes• focus lens•adjust light entering eye
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Cranial Nerve V
Trigeminal (V)• mixed• opthalmic division
• sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids
• maxillary division• sensory from upper teeth, upper gum, upper lip, palate, and skin of face
• 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
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Cranial Nerves VI and VII
Abducens (VI)• primarily motor• motor impulses to muscles that move the eyes• some sensory with proprioreceptors
Facial (VII)• mixed• sensory from taste receptors• motor to muscles of facial expression, tear glands, and salivary glands
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Cranial Nerves VIII and IX
Vestibulocochlear (VIII)• sensory• vestibular branch
•sensory from equilibrium receptors of ear
• cochlear branch •sensory from hearing receptors
Glossopharyngeal (IX)• mixed• sensory from pharynx, tonsils, tongue, and carotid arteries• motor to salivary glands and muscles of pharynx
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Cranial Nerve X
Vagus (X)• mixed• 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
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Cranial Nerves XI and XII
Accessory (XI)• primarily motor• cranial branch
• motor to muscles of soft palate, pharynx, and larynx
• spinal branch •motor to muscles of neck, and back; some proprioreceptor
Hypoglossal (XII)• primarily motor• motor to muscles of the tongue; some proprioreceptor
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Functions of Cranial Nerves
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Spinal Nerves
• mixed nerves
• 31 pairs• 8 cervical
•(C1 to C8)• 12 thoracic
•(T1 to T12)• 5 lumbar
•(L1 to L5)• 5 sacral
•(S1 to S5)• 1 coccygeal
•(Co)
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Spinal Nerves
Dorsal root (posterior or sensory root)
• axons of sensory neurons in the dorsal root ganglion
Dorsal root ganglion • cell bodies of sensory neurons whose axons conduct impulses inward from peripheral body parts
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Dermatome
• an area of skin that the sensory nerve fibers of a particular spinal nerve innervate
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Spinal Nerves
Ventral root (anterior or motor root)
• axons of motor neurons whose cell bodies are in spinal cord
Spinal nerve• union of ventral root and dorsal root
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Cervical Plexuses
Nerve plexus – complex networks formed by anterior branches of spinal nerves; fibers of various spinal nerves are sorted and recombined
Cervical Plexus• formed by anterior branches of C1-C4• lies deep in the neck• supply muscles and skin of the neck• C3 – C5 contribute to phrenic nerves
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Brachial Plexuses
• C5-T1• lies deep within shoulders• musculocutaneous nerves
• supply muscles of anterior arms and skin of forearms
• ulnar and median nerves• supply muscles of forearms and hands• supply skin of hands
•radial nerves• supply posterior muscles of arms and skin of forearms and hands
• axillary nerves• supply muscles and skin of anterior, lateral, and posterior arms
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Lumbosacral Plexuses
• T12 – S5
• extend from lumbar region into pelvic cavity
• obturator nerves • supply motor impulses to adductors of thighs
• femoral nerves• supply motor impulses to muscles of anterior thigh and sensory impulses from skin of thighs and legs
• sciatic nerves• supply muscles and skin of thighs, legs, and feet
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Plexuses
Cranial Nerve Assessment
http://www.youtube.com/watch?v=eLzkgPkgkEo
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Detailed Cranial Assessment
http://www.youtube.com/watch?v=G6FZR64Cq9U&feature=related
12 days of Christmas Cranial Nerve song
http://www.youtube.com/watch?v=4xzQ5vnvL-o&feature=related
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Autonomic Nervous System
• functions without conscious effort• controls visceral activities• regulates smooth muscle, cardiac muscle, and glands• efferent fibers typically lead to ganglia outside CNS
Two Divisions• sympathetic – prepares body for fight or flight situations• parasympathetic – prepares body for resting and digesting activities
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Autonomic Nerve Fibers
• all are neurons are motor (efferent)
• preganglionic fibers• axons of preganglionic neurons• neuron cell bodies in CNS
• postganglionic fibers• axons of postganglionic neurons• neuron cell bodies in ganglia
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Sympathetic Division
• thoracolumbar divison – location of preganglionic neurons
• preganglionic fibers leave spinal nerves through white rami and enter paravertebral ganglia
• paraverterbral ganglia and fibers that connect them make up the sympathetic trunk
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Sympathetic Division
• postganglionic fibers extend from sympathetic ganglia to visceral organs
• postganglionic fibers usually pass through gray rami and return to a spinal nerve before proceeding to an effector
• Exception: preganglionic fibers to adrenal medulla do not synapse with postganglionic neurons
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Sympathetic Division
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Parasympathetic Division
• craniosacral division – location of preganglionic neurons
• ganglia are near or within various organs
• terminal ganglia
• short postganglionic fibers
• continue to specific muscles or glands
• preganglionic fibers of the head are included in nerves III, VII, and IX
• preganglionic fibers of thorax and abdomen are parts of nerve X
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Parasympathetic Division
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Autonomic Neurotransmitters
Cholinergic Fibers• release acetylcholine• preganglionic sympathetic and parasympathetic fibers• postganglionic parasympathetic fibers
Adrenergic Fibers• release norepinephrine• most postganglionic sympathetic fibers
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Actions of AutonomicNeurotransmitters• depend on receptors in the membrane
Cholinergic receptors• bind to acetlycholine• muscarinic
• excitatory • slow
• nicotinic• excitatory• rapid
Adrenergic Receptors• bind to epinephrine and norepinephrine• alpha and beta
• both elicit different responses on various effectors
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Insert figure 11.39
Actions of AutonomicNeurotransmitters
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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
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Life-Span Changes
• Brain cells begin to die before birth• Over average lifetime, brain shrinks 10%• Most cell death occurs in temporal lobes• By age 90, frontal cortex has lost half its neurons• Number of dendritic branches decreases• Decreased levels of neurotransmitters• Fading memory• Slowed responses and reflexes• Increased risk of falling• Changes in sleep patterns that result in fewer sleeping hours
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Clinical Application
Cerebral Injuries and Abnormalities
Concussion• brain jarred against cranium• loss of consciousness• temporary loss of memory• mental cloudiness• headache• recovery usually complete
Cerebral Palsy• motor impairment at birth• caused by blocked cerebral blood vessels during development• seizures• learning disabilities
Cerebrovascular Accident• stroke• sudden interruption in blood flow• brain tissues die
