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THE NERVOUS SYSTEM

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THE NERVOUS SYSTEM Chapter 7 CSF returns to blood in dural venous sinuses through _____ Normal means CSF forms and drains at a constant rate ... – PowerPoint PPT presentation

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Title: THE NERVOUS SYSTEM


1
THE NERVOUS SYSTEM
  • Chapter 7

2
  • Monitors changes-__________________________--insid
    e and outside the body
  • Processes and interprets input-___________________
    _____________
  • Effects a response by activating muscles or
    glands(effector)via_______________________________
    ______

Stimuli and gathered info is sensory input
integration
Motor output
3
Organization of the Nervous System
4
  • Divided by structure and activities
  • Structural classification
  • _____________________________________-consists of
    brain and spinal cord and is integrating command
    center
  • __________________________________-part of system
    outside CNS-nerves extending beyond the brain and
    SC
  • _______________________________-carry messages to
    and from SC and
  • ______________________________-carry impulses to
    and from brain

CNS
Spinal nerves
Cranial nerves
Peripheral nervous system
5
Functional classification
  • Divides peripheral nervous sytem into 2 divisions
  • __________________or afferent division consists
    of nerves conveying info to CNS via sensory
    receptors in the body
  • __________________________-bring in impulses from
    skin,skeletal muscles and joints
  • ________________________________bring in messages
    from inside and outside the body

Visceral or sensory fibers or afferents
sensory
Somatic sensory fibers
6
effect
Somatic nervous system
Voluntary nervous sysyem
  • Motor or efferent division carry impulses from
    CNS to effector organs-muscles and glands-They
    _________a motor response
  • a)______________________allows us to
    consciously,or voluntarily control skeletal
    musces-so this sytem is also called
    ______________________________/some skeletal
    responses are initially involuntary
  • b) __________________ regulates autonomic or
    involuntary-like smooth muscle ,cardiac muscle
    and glands..commonly called _____________________
    _,which has 2 parts 1)sympathetic-opposes
    parasympathetic-associated w/ flight or fight
    2)parasympathetic division-opposes sympathetic
    and craniosacral division

Involuntary NS
Autonomic nervous system
7
Nervous TissueStructure and Function
  • Either supporting cells or neurons
  • Supporting Cells-limped together as neuroglia and
    includes cells that generally support,insulate
    and protect delicate neurons---glial cells have
    special functions

8
  • ______________________________-abundant star
    shaped cells-swollen ends that cling to
    neurons,bracing them and anchoring to nutrient
    supply________________________/They form a
    living barrier between capillaries and neurons
    and help make exchange between the 2-help protect
    neurons from harmful substances in the blood and
    also help control brain chemical environment by
    moppingup leaked K ions and recapturing
    released neurotransmitters
  • _____________________________-spider like
    phagocytes to dispose of debris-like dead brain
    cells and bacteria

astrocytes
microglia
capillaries
9
ependymal
oligiodendrocytes
  • _____________________________-glial cells that
    line the central cavities of the brain and SC
    ..beating of cilia to distribute cerebrospinal
    fluid for those cavities and provide a cushion
  • _________________________________-glia that wrap
    flat extensions tightly around nerve
    fibers-producing fatty myelin sheath(an
    insulation)
  • 2 major varieties in PNS______________________for
    m myelin sheath and ______________________________
    -positive cushioning cells

Schwann cells
Satellite cells
10
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12
Neurons-- anatomy-all have cell body,which
contains nucleus and is metabolic center and one
or slender extending processes
  • Neurons-- anatomy-all have cell body,which
    contains nucleus and is metabolic center and one
    or slender extending processes
  • Cell Body-metabolic center
  • Transparent ________________ w/ a conspicuous
    nucleolus
  • Cytoplasm has usual organelles except centrioles
  • Rough ER is called______________________________an
    d _____________________________(intermediate
    filaments used in maintaining cell shape)

Nissal substance
nucleus
neurofibrils
13
  • Processes-or fibers- vary greatly in length from
    microscopic - 3-4 ft.Our longest reach from
    lumbar to large toe
  • ________________________-convey incoming
    messages(electrical signals) towards cell
    body-may be many of these for one nerve cell
  • _____________________- carry messages AWAY from
    cell body-only 1 axon,but branch much 2 end
    w/hundreds of axon _____________________________.-
    they contain 100s of tiny vesicles,or
    membranous sacs w/___________________________chemi
    cals-released into extracellular space

Axon terminals
axons
dendrites
neurotransmitters
14
  • _____________________________tiny gap that
    separates axon terminal from next neuron(synapse)
  • _____________________________-whitish ,fatty
    material w/waxy appearance.It functions by
    insulating or protecting fibers and Increases
    transmission rate

Myelin sheath
Synaptic cleft
15
  • Axons outside CNS are myelinated by
    ____________________________,which is gradually
    squeezed tightly enclosing axon
  • External to Schwann cell is neurilemma-

Schwann cells
16
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17
  • Gaps between Schwann cells are called
    __________________________
  • Myelinated fibers also in CNS as
    ___________________________-around small segment
    of 1 nerve fiber-coiling around as many as 60
    fibers at one timeSince they lack neurilemma
    that contributes to non regeneration property

Nodes of Ranvier
oligodendrites
18
  • __________________________________is a
    neurological disorder causing visual or speech
    problems as wel as increasingle degenerating
    muscle This is all due to an autoimmune response
    that destroys a protein in the myelin and cause
    nerves to short ciruit----Interferon is used

Multiple sclerosis
19
Terminology-
nuclei
ganglia
  • -
  • cell bodies in CNS are usually called
    ______________--carrying out metabolic
    functions/not regenerated
  • __________________small collections of cell
    bodies outside CNS-in PNS
  • ________________________ are bundles of nerve
    fibers running through CNS
  • _____________________________________ are bundles
    of nerve fibers running through PNS
  • _________________________-collections of
    myelinated fibers in CNS
  • ________________________CNS unmyelinated fibers

nerves
tracts
Gray matter
White matter
20
Classification
Sensory or afferent
  • Functionally groups neurons according to
    direction of nerve transmission relative to
    CNSif carrying impulse from receptor to
    CNS-____________________________neurons-found in
    a ganglion outside CNSdendrite endings of
    sensory neurons are usually associated with
    specialized recptors activated by specific nearby
    changes-cutaneous sense organs and________________
    _____________in muscle and tendons

proprioreceptors
21
  • _________________(efferent)neurons carry
    impulses from CNS to visceraan/or muscles or
    glands-cell bodies in CNS
  • ________________________or association neurons
    connect motor and sensory neurons in neural
    pathways-cell bodies always in CNS
  • Structurally based on of processes extending
    from cell body---if several______________________
    ______-inc. all motor and association
    neurons/__________________neurons have 2
    processes-rare in adults/_____________________neur
    ons have single process sensory neurons in PNS

motor
interneurons
multipolarneuron
bipolar
Unipolar neurons
22
6-Physiology
23
  • NERVE INPULSESNeurons have 2 major
    properties-_______________________________________
    ____
  • __________________________refers to inactive or
    resting plasma membrane(fewer ions on inner
    face(Kions)-outside are Na ions if the inside
    is more - ,it is inactive

Irritability and conductivity
polarized
24
depolarization
Action potential
repolarization
  • Action Potential and generationmany different
    stimuli excite neuronseg.light,sound,pressure-mos
    t excited by neurotransmitters released by other
    neurons.changes permeability of membrane changes
    briefly-gates of Na channels open---changing
    polarity-_________________________-inside now
    more --graded potential
  • If this strong enough it initiates
    an_________________________(nerve impulse)-all-or
    none response
  • An outflow now of K ions will restore resting
    state-__________________________________

25
  • UNTIL REPOLARIZATION HAPPENSltA NEURON CANNOT
    CARRY ANOTHER IMPULSE !
  • NA-K pump uses ATP
  • The above describes unmyelinated impulses
    Myeinated sheaths conducts impulses
    faster-__________________________________-leaps
    from node to node
  • Conductivity can be impaired by sedatives and
    anesthetics by altering permeability

Salatory conduction
26
  • Synapse Transmission-impulse does not traverse-
    synapse neurotransmitter do and they cause Na
    entry ,depolarization,etc.-brief
    transmission-electrochemical

27
  • Reflexes-rapid and predictable and involuntary
    response to stimuli
  • Somatic reflexes-stimulate skeletal muscles
  • _____________________regulate smooth
    muscles,heart and glands

Autonomic reflexes
28
  • _____________________________is a neural pathway
    and has at least 5 elements______________________
    __________________________________________________
    ____________________________

Sensory receptor,effector organ,sensory or motor
neurons and synapse-CNS integration center
Relex arcs
29
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30
III. CNS
gyri
sulci
  • Functional Anatomy of the Brain
  • Brain is 3 lbs.
  • 4 regions-cerebral,diencephalons,brain
    stem,cerebellum
  • Cerebral hemispheres
  • Paired
  • Largest and most superior
  • ____________-elevated regions of tissue separated
    by shallow _______
  • ______________________are less numerous grooves
    and separate larger regions of brain

fissures
31
Longitudinal fissure
  • ______________-separates 2 hemispheres by deep
    fissure
  • Other fissures or sulci divide into lobes,named
    for corresponding cranial bone
  • 3 basic regions to ea hemisphere_________________
    ______

Superficial cortex of gray matter,internal white
matter,and basal ganglia(Gray)
32
Cerebral Cortex-includes speech,memory,logical
and emotional response, consciousness ,
interpretation of sensation,and voluntary movement
  • ________________________-posterior to central
    sulcus-primary somatic sensory area-interprets
    impulses traveling from body sensory
    receptors(except for special senses)/allows you
    to perceive pain,coldness or light touch.as
    shown in 7-14,p.245body is represented in an
    upside down manner in sensory area-such a spatial
    map is a ___________________-crossed
    pathways-left primary somatic sensory area
    receives impulse from right and vice verse

Primary somatic sensory area in parietal lobe
Sensory homunculus
33
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35
  • __________________________visual area in
    posterior
  • ___________________________has auditory area and
    has olafactory area
  • _________________________is primary motor
    area/the axons of these motor neurons make
    ________-major voluntary motor tract and it
    descends to cord-pathways again crossed
  • _________is map on motor cortex

Temporal lobe
Occipital lobe
Corticospinal or pyramidal tract
Motor homunculus
Frontal lobe
36
  • ______________________at base of precentral
    gyrus-involved in speech-usually only in left
    hemisphere-damage here can cause inability to say
    words properly
  • In anterior frontal lobes is believed to be
    intellectual reasoning and socially acceptable
    behavior region
  • The main _____________________is located at
    junction of temporal,parietal,and occipital
    lobes-usually only in 1 hemisphere also
  • __________________is involved w/word meanings
  • Cell bodies of neurons involved in cerebral
    hemisphere are in outermost gray matter

Speech area
Brocas area
Frontal lobes
37
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40
Cerebral White Matter-deeper,remaining
cerebrum-composed of fiber tracts carrying
impulses to and from or within cortex
  • __________________________________-large fiber
    tract that connects cerebral hemispheres(an
    example of a commisure)-allows hemispheres to
    communicate with each other.Association fiber
    tracts connects areas w/in hemisphere and
    projection fiber tract connects cerebrum

Corpus callosum
41
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42
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43
  • _______________________________-islands of gray
    matter buried in white matter of cerebral
    hemispheres-help regulate voluntary motor
    activities by modifying instructions-esp.
    starting or stopping
  • basal ganglia

Basal nuclei
44
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45
  • ______________________________- genetic disease,
    middle-age and leads to massive degeneration of
    basal nuclei and then cerebral cortex-includes
    jerky movements and an eventual vegetative state
    w/in 15 years fatal-overdrive in motor
    stimulation
  • ______________-has basal nuclei problems-strikes
    in 50s-60s and comes from a degeneration of
    dopamine releasing neurons-dopamine deprived
    basal nuclei become overactive-tremors,head
    nodding etc.

Huntingtons disease or Chorea
Parkinsons disease
46
Diencephalon-interbrain-atop brain stem and
enclosed by cerebral hemispheres
  • ____________________________-encloses shallow 3rd
    ventricle of brain and is relay station for
    sensory impulses passing upward to sensory
    cortex-interpret sensation
  • ____________________________________-is under the
    thalamus makes up floor of diencephalons-helps
    regulate body temp.,water balance
    and,metabolism-also centers for many drives and
    emotions-part of ___________________________-emot
    ional visceral brain-thirst,appetite and sex
    drive

Thalamus
hypothalamus
Limbic System
47
  • Contains pituitary gland and mammillary bodies
    that is involved in olafaction

48
  • ___________________-roof of 3rd
    ventricle/contains ____________________-an
    endocrine organ,choroid plexus-form cerebrospinal
    fluid

Pineal body
epithalamus
49
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50
____________________________________-about the
size of a thumb in diameter and about 3
longincludes midbrain,pons and medulla
oblongata/provides a pathway for ascending and
descending tracts and has small gray matter areas
  • 1)____________________________-small/_____________
    _______________________ travels through midbrain
    and anteriorly midbrain has cerebral peduncles
    that convey ascending and descending
    impulses/dorsally are 4 rounded corpora
    quadrigemina-reflex centers for vision and hearing

midbrain
Brain stem
Cerebral aqueduct
51
  • 2)___________________----rounded just below
    midbrain and has bridge of fiber tracts and
    involves in control of breathing
  • 3)___________________________-most inferior part
    and merges into SCfiber tract area and helps
    regulate visceral activity

pons
Medulla oblongata
52
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53
Cerebellum-dorsally under occipital lobe and
has 2 hemispheres-has outer cortex of gray matter
and inner cortex of white matter
  • Provides timing factor for skeletal and controls
    muscle activity
  • ________________________-cerebellum damage
    causing clumsiness and disorganization

ataxia
54
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56
Protection of CNS
  • A.__________-3 connective tissue membranes
    protecting CNS
  • 1)______________________-outermost layer and
    leathery(tough or hard mother),double layered
    where surrounds brain

Dura mater
meninges
57
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58
  • _____________________-attached to inner surface
    of skull
  • ___________________-Outermost covering of brain
    and continues as dura mater of spinal cord
  • Dural layers fused except in 3 areas where they
    separate to enclose dural venous sinuses that
    collect _________________________.

Periosteal layer
Meningeal layer
Venous blood
59
Inner dural membrane extends inward to form a
fold that attaches brain to cranial cavity
60
______________________________-middle meningeal
layer,weblikespans subarachnoid space to attach
TO innermost membrane.
Arachnoid mater
61
  • 3)_____________________________-innermost
    membrane(gentle mother)-clings tightly to
    surface of brain and spinal cord,following every
    fold
  • Subarachnoid space is filled w/ cerebrospinal
    fluid and ______________________________protrude
    through dura mater
  • Cerebrospinal fluid is absorbed into venous blood
    in dural sinuses through arachnoid villi

Projections of arachnoid membrane called
arachnoid villi
Pia mater
62
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encephalitis
  • ______________________________-inflammation of
    meninges,serious threat to brain(bacterial or
    viral) because may spread to the nervous tissue
    of the CNS/spinal diagnostic taps derived from
    subarachnoid space
  • ___________________________-brain inflammation

meningitis
64
Cerebrospinal Fluid(CSF)-somewhat watery and
similar to blood plasma,but contains less protein
and more vitamin C and a different ion
composition
  • CSF continually formed from blood by choroids
    plexus(clusters of capillaries hanging from roof
    of each of brains ventricles)
  • Forms a watery cushion to protect fragile nervous
    tissue
  • Continually moves in brain,circulating from 2
    _________________________into 3rd ventricle and
    then through cerebral aquaduct of midbrain into
    4th ventricle.some of this continues down SC,but
    most circulates into subarachnoid space

Lateral ventricles
65
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66
  • CSF returns to blood in dural venous sinuses
    through _____________________________
  • Normal means CSF forms and drains at a constant
    rate maintaining about ½ cup fluid.Any
    significant changes-like blood cells or general
    composition may mean ____________________
  • Test w/ lumbar puncture
  • ________________________________--if drainage of
    CSF is obstructed-maybe by tumor or born that way

Sign of miningitisor certain brain pathologies
such as tumor or MS
Arachnoid villi
hydrocephalis
67
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68
Blood-Brain Barrier
  • Brain is very sensitive to pressure and chemical
    changes
  • Thus,the least permeable capillaries in
    bodyalmost seamlessly bound by tight junctions
    all around-passing only water ,glucose and amino
    acids pass easily throughpreventing
    _________________________
  • Barrier useless against __________________________
    __(thus explains entrance of alcohol,nicotine and
    anesthetics

Preventing urea, toxins,proteins and many drugs
from entering
Fats,respiratory gases and other fat-soluble
molecules
69
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70
Brain Dysfunctions
  • _______________________________-progressive
    degenerative disease of brain resulting,eventually
    , in dementiaassociated w/shortage of Ach and
    structural changes in braingyri shrink and brain
    atrophies
  • _______________________-minor and not permanent
    brain damage
  • __________________________-marked tissue
    destruction-severe forms always result in comas

concussion
Alzheimers disorder
contusion
71
  • ____________________________-after a blow to the
    head-bleed from ruptured vessels
  • ________________________-swelling of brain from
    inflammatory response to injury
  • ______________________________-3rd leading cause
    of death in US-when blood circulation is blocked
    and vital tissue dies
  • ____________________one sided paralysis
  • _________________damage to left cerebrum and
    affects speech
  • __________________-temporary restriction of blood
    flow

Cerebral edema
Cerebrovascular accidents-CVA-ie.stroke
Intracranial hemorrhage
hemiplegia
aphasias
Transient ischemic attack -TIA
72
SPINAL CORD-cylindrical and appx.17
long,glistening white2 way conduction pathway to
and from brain and reflex center
  • Extends from foramen magnum to ___________________
    ______________,ending below the ribs(thus L3 good
    for spinal tap)
  • Protected by CSF and meningeal coverings
  • 31 prs spinal nerves-arise from cord and exit
    from vertebral column to serve nearby area of
    body
  • ____________________collection of spinal nerves
    at end of vertebral canal

Cauda equina
1st or 2nd lumbar vertebra
73
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75
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76
A)Gray matter of SC and spinal roots
  • Looks like butterfly in crosssection
  • Contains dorsal horns(has interneurons) ,ventral
    horns(contain cell bodies of motor
    somaticvoluntary nervous sytem and surrounds
    central canal of SC ,containing CSF)
  • Cell bodies of sensory neurons enter cord by
    dorsal root and are called _______________________
    ____________-If severed ,sensation at that point
    is lost
  • Ventral horn sends its axons out
    ______________________
  • Dorsal and ventral roots fuse to form
    ________________________________
  • ____________________________-damage to ventral
    root/affecting muscles servedmuscles will
    atrophy

Flaccid paralysis
Spinal nerves
Dorsal root ganglion
Ventral root of cord
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B-White matter of SC
  • Myelinated fiber tracts-serving higher
    centers,some travel brain to SC and some
    innervate one or the other side of the SC
  • Dorsal,lateral and ventral columns-3 regions of
    white matter
  • Tracts conducting Sensory impulse to brain by
    _________________or afferent tracts
  • Motor(efferent tracts) carry from
    __________________________________
  • __________________________________-if SC is cut
    crosswise or crushed-afferent stay intact and
    involuntary movement of those muscles results and
    sensation loss below cut-compare quadriplegic to
    paraplegic

Marieb, E. N. (2009). Essentials of Human Anatomy
and Physiology (9th ed.). San Francisco,
California Pearsonincludes images
Brain to skeletal muscles
sensory
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