Download Nervous System

Nervous System
Chapter 9
Master controlling and communicating
system of the body
Three overlapping functions
Uses its sensory receptors to monitor
changes occurring outside/inside body
(sensory input)
Processes and interprets the sensory
input (integration)
Causes a response by activating
effector organs (motor output)
9.1: Introduction
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Dendrites
• Cell types in neural tissue:
• ______________
• ______________
Cell body
Nuclei of
neuroglia
Axon
© Ed Reschke
3
Divisions of the Nervous System
• Central Nervous System (CNS)
• _______
• __________
• Peripheral Nervous System (PNS)
• Sensory Nervous system
• Motor Nervous system
• ____________
• ____________
• Cranial nerves
• Spinal nerves
4
Divisions Nervous System
Central Nervous System
(Brain and Spinal Cord)
Brain
Peripheral Nervous System
(Cranial and Spinal Nerves)
Cranial
nerves
Sensory division
Spinal
cord
Sensory receptors
Spinal
nerves
Motor division
(a)
(b)
Somatic
Nervous
System
Skeletal muscle
Autonomic
Nervous
System
Smooth muscle
Cardiac muscle
Glands
6
9.2: General Functions of
the Nervous System
• Sensory Function
• Sensory receptors gather information
• Information is carried to the CNS
• Integrative Function
• Sensory information used to create sensations, memory,
thoughts, decisions
• Motor Function
• Decisions are acted upon
• Impulses are carried to __________
• Divisions of motor functions of PNS
• Somatic – _______________
• Autonomic – _______________
7
9.3 Neuroglia
Required for
neuron existence
Provide
structural
framework
Insulate
Phagocytize
Greatly
outnumber
neurons in CNS
Can divide
Types of Neuroglial Cells
in the CNS
1) _________
3) ___________
• Scar tissue
• Phagocytic cell
• Aid metabolism of certain
• Form scars in areas of
substances
damage
• Induce synapse formation
• Connect neurons to blood
4) _________________
vessels
• Line central canal of spinal
• Part of Blood Brain Barrier
cord
• Line ventricles of brain
2) ___________
• Myelin sheath around brain
•5) ____________
and spinal cord
•Myelin sheath around axons
• Insulation
of myelinated neurons 9
Types of Neuroglial Cells
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Page 227
Fluid-filled cavity
of the brain or
spinal cord
Neuron
Ependymal
cell
Oligodendrocyte
Astrocyte
Microglial cell
Axon
Capillary
Myelin
sheath (cut)
Node of
Ranvier
12
Neuroglia and Axonal Regeneration
Neurons _______ divide
If cell body is injured, the neuron
usually dies
If a peripheral axon is injured, it may
regenerate
13
Neuroglia and Axonal Regeneration
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Skeletal
muscle fiber
Motor neuron
cell body
Changes
over time
Site of injury
Schwann cells
Axon
(a)
Distal portion of
axon degenerates
(b)
Proximal end of injured axon
regenerates into tube of sheath cells
(c)
Schwann cells
degenerate
(d)
Schwann cells
proliferate
(e)
Former connection
reestablished
14
9.4: Neurons
• Neurons vary in size and shape
• They may differ in length and size of their axons and dendrites
• Neurons share certain features:
• Dendrites – ___________
• A cell body – ___________
• An axon – ______________
15
Neuron Structure
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chromatophilic
substance
(Nissl bodies)
Dendrites
Cell body
Nucleus
Nucleolus
Neurofibrils
Axon
hillock
Impulse
Axon
Synaptic knob of
axon terminal
Nodes of Ranvier
Myelin (cut)
Axon
Nucleus of
Schwann cell
Schwann
cell
Portion of a
collateral
16
Microscopic Neuron Structure
Cell body contains granular cytoplasm,
mitochondria, lysosomes, a Golgi
apparatus, and many microtubules
A network of fine threads called
neurofibrils extends into the axon and
supports it
________ are highly branched,
numerous and provide receptive surfaces
for communication between neurons
The ______ (only one) arises from a
slight elevation of the cell body. It is a
slender, cylindrical process with a nearly
smooth surface and uniform diameter
Specialized to conduct nerve impulses
______ from the cell body
May have extensions near its end, each
ending in an axon terminal with a
synaptic knob
Synaptic knob is separated from
another cell by the synaptic cleft
Larger axons of peripheral neurons are
enclosed in sheaths composed of many
Schwann cells
Portions of the Schwann cells that contain
most of the cytoplasm and nuclei remain
outside the myelin sheath and comprise a
neurilemma which surrounds the myelin
sheath
___________– narrow gaps in the myelin
sheath between Schwann cells
Myelination of Axons
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• Axons which are tightly
wrapped by neuroglial cells
are termed myelinated.
•______ Matter
• Contains myelinated
axons
• Considered fiber tracts
• ______ Matter
• Contains unmyelinated
structures
• Cell bodies, dendrites
Dendrite
Unmyelinated
region of axon
Myelinated region of axon
Node of Ranvier
Axon
(a)
Neuron
Neuron
cell body nucleus
Enveloping
Schwann cell
Schwann
cell nucleus
Longitudinal
groove
(c)
Unmyelinated
axon
20
Classification of Cells of the
Nervous System
• Neurons vary in function
• They can be sensory, motor, or integrative neurons
• Neurons vary in size and shape, and in the number of axons
and dendrites that they may have
• Due to structural differences, neurons can be classified into
three (3) major groups:
• Bipolar neurons
• Unipolar neurons
• Multipolar neurons
22
Classification of Neurons:
Structural Differences
• __________ neurons
• 99% of neurons
• Many processes
• Most neurons of
CNS
• _________ neurons
• Two processes
• Eyes, ears, nose
• _________ neurons
• One process
• Ganglia of PNS
• Sensory
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Dendrites
Peripheral
process
Axon
Direction
of impulse
Central
process
Axon
(a) Multipolar
Axon
(b) Bipolar
(c) Unipolar
23
Classification of Neurons:
Functional Differences
• ____________ Neurons
• Afferent
• Carry impulse to CNS
• Most are unipolar
• Some are bipolar
• _____________
• Link neurons
• Multipolar
• Located in CNS
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Central nervous system
Peripheral nervous system
Cell body
Dendrites
Sensory
receptor
Cell body
Axon
(central process)
Axon
(peripheral process)
Sensory (afferent) neuron
Interneurons
Motor (efferent) neuron
Axon
Effector
(muscle or gland)
• _________ Neurons
• Multipolar
• Carry impulses away from CNS
• Carry impulses to effectors
Axon
Axon
terminal
25
9.5: The Synapse
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Nerve impulses pass
from neuron to neuron
at ________, moving
from a __________to a
___________.
•Neurotransmitters
released at synapse
Synaptic
cleft
Impulse
Dendrites
Axon of
presynaptic
neuron
Axon hillock of
Postsynaptic neuron
Axon of
presynaptic
neuron
Impulse
Cell body of Impulse
postsynaptic
neuron
27
Synaptic Transmission
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Neurotransmitters are
released when impulse
reaches synaptic knob
(synaptic transmission)
Direction of
nerve impulse
Axon
Ca+2
Synaptic knob
•Some neurotransmitters
increase (excitatory)
actions and some decrease
(inhibit) actions
Synaptic
vesicles
Presynaptic neuron
Ca+2
Cell body or dendrite
of postsynaptic neuron
Mitochondrion
Ca+2
Synaptic
vesicle
Vesicle releasing
neurotransmitter
Axon
membrane
Neurotransmitter
Synaptic cleft
Polarized
membrane
Depolarized
membrane
(a)
28
Quiz 1
9.6: Cell Membrane Potential
• A cell membrane is usually electrically charged, or
polarized, so that the inside of the membrane is _________
charged with respect to the outside of the membrane (which is
then positively charged).
• This is as a result of unequal distribution of ions on the
inside and the outside of the membrane.
•A change in neuron membrane polarization and return to
resting state (action potential) forms an impulse that is
propagated along the axon
30
Distribution of Ions
• Potassium (K+) ions are the major __________ positive ions
(cations) and pass through the membrane easier than sodium;
therefore, potassium major contributor to membrane polarization.
• Sodium (Na+) ions are the major _________ positive ions (cations).
• This distribution is largely created by the Sodium/Potassium Pump
(Na+/K+ pump) but also by ion channels in the cell membrane. The
pump actively transports sodium ions out of the cell and potassium
ions into the cell.
31
Resting Potential
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• Resting Membrane Potential
(RMP):
• _____ difference from
inside to outside of cell
• It is a polarized
membrane
• Inside of cell is negative
relative to the outside of
the cell
• RMP = -70 mV
• Due to distribution of
ions inside vs. outside
• Na+/K+ pump restores
High Na+
Low Na+
Impermeant
negative ions
High K+
Axon
Cell body
Low K+
(a) If we imagine a cell before the membrane potential
is established, concentration gradients are such that
diffusion of potassium ions out of the cell exceeds
diffusion of sodium ions into the cell, causing a net
loss of positive charge from the cell.
Axon terminal
+
–
+
–
+
–
+
+
–
–
+
+
–
+
–
–
–
+
–
+
–
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–
+
–
+
–
+
+
–
–
+
+
–
–
+
–70 mV
+
–
+
–
High Na+
Low
+
–
(b) The net loss of positive charges from the inside
of the cell has left the inside of the cell membrane
slightly negative compared to the outside of the
membrane, which is left slightly positive. This
difference (an electrical “potential difference”) is
measured as –70 millivolts (mV) in a typical neuron,
and is called the resting membrane potential.
+
–
Na+
Pump
K+
High K+
Low K+
+ –
+
–
+
–
Na+
–
+
–
+
–
+
–
+
–
+
+
–
–
+
+
–
–
+
–70 mV
(c) With the membrane potential established, sodium diffusion into the cell
is now aided, and potassium diffusion opposed, by the negative charge on
the inside of the membrane. As a result, slightly more sodium ions enter the
cell than potassium ions leave, but the action of the sodium/potassium pump
balances these movements, and as a result the concentrations of these ions,
and the resting membrane potential, are maintained.
32
Local Potential Changes
• Caused by various stimuli:
• Temperature changes
Gate-like mechanism
• Light
• Pressure
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Protein
Cell
membrane
(a) Channel closed
Fatty acid
tail
Phosphate
head
(b) Channel open
• Environmental changes affect the membrane
potential by opening a gated ion channel
• Channels are 1) ___________, 2) __________,
3) _____________
or
33
Local Potential Changes
• Environmental changes can cause gated ion channels to open
• As ions then flow through the membrane, the membrane potential
changes
• If membrane potential becomes more negative, it has ____________
• If membrane potential becomes less negative, it has __________
• Graded (or proportional) to intensity of stimulation reaching
threshold potential
• Reaching threshold potential triggers voltage gated channels to
open, causing an action potential
•
34
Local Potential Changes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Na+
Na+
–62 mV
Neurotransmitter
(a)
Chemically-gated
Na+ channel
Presynaptic
neuron
Voltage-gated
Na+ channel
Trigger zone (axon hillock)
Na+
Na+
Na+
Na+
Na+
–55 mV
(b)
35
Action Potentials
________at first part of axon contains many voltage gated
sodium channels
Voltage gated Na+ channels open in response to threshold
As Na+ moves in the membrane depolarizes until it reaches
+30 mV (action potential)
Na+ channels close and K+ channels open
K+ moves out and membrane repolarizes
As membrane potential drops below ______, the membrane
is hyperpolarized
Active transport reestablishes the resting potential of
-70mV as Na+ and K+ concentrations are maintained
36
Action Potentials
Page 238
• At rest, the membrane is
polarized (RMP = -70)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Na+
• Threshold stimulus
reached (-55)
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
Na+
Na+
Na+
Na+
–0
–70
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
(a)
• Sodium channels open
and membrane
depolarizes (toward 0)
K+
Na+
Na+
K+
Na+
K+
K+
K+
K+
K+
K+
K+
K+
K+
K+
–0
K+
Threshold
stimulus K+
K+
Na+
Na+ channels open
K+ channels closed
K+
Na+
Na+
–70
• Potassium leaves
cytoplasm and
membrane repolarizes
(+30)
• Brief period of
hyperpolarization (-90)
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
Region of depolarization
(b)
K+
K+
Na+
K+
Na+
K+
Na+
Na+
Na+
K+
K+
K+
K+
K+
K+
Na+
Na+
Na+
K+
K+
K+
K+
K+
K+
K+
K+
Na+
Na+
Na+
Na+
Na+
Na+
Na+
–0
K+ channels open
Na+ channels closed
–70
Na+
Region of repolarization
(c)
37
Action Potentials
Recording of an action potential
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Page 236
+40
Membrane potential (millivolts)
Action potential
+20
0
–20
Resting potential
reestablished
–40
Resting
potential
–60
–80
Hyperpolarization
0
1
2
3
4
5
6
7
8
Milliseconds
38
Action Potentials
A nerve impulse is the propagation of action
potentials down the length of an axon.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Region of action potential
Page 239
+
+
+
+
+
+
+
+
+
+
+
–
–
–
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–
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–
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–
–
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–
+
+
+
+
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+
+
+
+
+
+
+
+
+
+
–
–
–
–
–
–
–
–
–
–
–
–
+
+
+
+
(a)
+
+
+
–
–
–
+
+
Direction of nerve impulse
–
–
–
+
+
+
+
+
+
+
+
+
+
–
–
–
–
–
–
–
+
+
–
–
–
–
–
–
–
–
–
+
+
–
–
+
+
+
+
+
+
+
+
+
+
+
+
(b)
+
(c)
+
+
39
All-or-None Response
• If a neuron axon responds at all, it responds completely –
with an ____________ (nerve impulse)
• A nerve impulse is conducted whenever a stimulus of
threshold intensity or above is applied to an axon
• All impulses carried on an axon are the ____________
• A greater intensity of stimulation produces more impulses
per second, not a stronger impulse
40
Refractory Period
• _________ Refractory Period
• Time when threshold stimulus does not start another action
potential
•The axon’s voltage-gated Na+ channels are not responsive at
all and the axon can not be stimulated
• _________ Refractory Period
• Membrane is reestablishing its resting potential
• Time when stronger threshold stimulus can start another
action potential
• Limits how many action potentials may be generated in a
neuron in a given period
41
9.7 Impulse Conduction
The speed of impulse conduction
varies on different types of neurons.
Myelinated axons transmit impulses
through _________, which is faster
than impulses along unmyelinated
axons (jumps from node to node)
Thick axon fibers transmit faster
impulses than thin axon fibers.
42
Page 377
43
9.8: Synaptic Transmission
• This is where released neurotransmitters cross the
synaptic cleft and react with specific molecules called
receptors in the postsynaptic neuron membrane.
• Effects of neurotransmitters vary
•
Some are _________ (ones that release Na+ ions)
•
Some are _________
• Some neurotransmitters may open ion channels and
others may close ion channels.
• Chemically gated ion channels respond to
neurotransmitter, creating synaptic potentials.
45
Neurotransmitters
100 types identified in the nervous system that
are released by different neurons – some
release more than one type
Most synthesized in _________ and stored in
___________
After release some are decomposed by
enzymes in the synaptic cleft while others can
either diffuse to nearby neurons or be
reabsorbed by the synaptic knob for future
release
9.9 Impulse Processing
Neurons organized into neuronal pools that
work together to perform a common
function
Each pool receives input and generates
output – either excites or inhibits
__________ – stimulation of a neuron that
increases responsiveness to further stimulation
__________ – a neuron receives impulses from
two or more neurons
__________ – impulses leaving a neuron that
pass to other output neurons
9.10 Types of Nerves
_________ (afferent) = conduct
impulses into the brain and spinal cord
_________ (efferent) = carry
impulses to muscles or glands
________ = nerves that include both
sensory and motor
9.11 Nerve Pathways
Routes that impulses follow as they
travel through the nervous system
__________= simplest and includes only
a few neurons (sensory – inter – motor)
Reflexes are automatic subconscious
responses to changes (stimuli); help
maintain homeostasis (ie. Heart rate,
breathing rate, BP, swallowing, sneezing,
coughing)
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
(a)
Central
Nervous
System
Motor or
efferent neuron
Effector
(muscle or gland)
54
________________________ = simple reflex
that has only two neurons (sensory/motor)
______________ = rapid withdrawal of
a body part from a painful stimulus
Reflex Arcs
Page
245
57
9.12: Meninges
• Membranes of CNS
• Protect the CNS
• Three (3) layers:
• __________
• Outer
• internal periosteum of
of skull bones
• Blood vessels
• __________
• Middle
• Space contains
cerebrospinal fluid
(CSF)
• _________
• Inner
• Blood vessels
• Nourishes CNS
58
Meninges of the Spinal Cord
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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
60
Quiz 2
9.13: 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 the __________
and terminates ___________
Brainstem
Foramen
magnum
Cervical
enlargement
Cervical
enlargement
Spinal cord
Vertebral
canal
Lumbar
enlargement
Lumbar
enlargement
Conus
medullaris
Cauda
equina
Conus
medullaris
Filum
terminale
(a)
(b)
62
Structure of Spinal Cord
Consists of 31 segments – each giving rise
to a pair of spinal nerves that branch to
various body parts
In the neck the cervical enlargement
(thickened area) supplies nerves to the
upper limbs
In the lower back the lumbar enlargement
supplies nerves to the lower limbs
Two grooves extend the length of the
spinal cord and divide it into right and
left halves = _________ and
___________
Cross section reveals the cord consists
of a core of gray matter within the white
matter that is shaped like a butterfly
that is surrounded with nerve tracts that
are either ascending or descending
Structure of the Spinal Cord
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Posterior median Posterior horn
sulcus
White matter
Posterior
funiculus
Gray matter
Lateral funiculus
Gray commissure
Central canal
Dorsal root
of spinal nerve
Lateral horn
Dorsal root
ganglion
Anterior
horn
Portion of
spinal nerve
(a)
Ventral root
of spinal nerve
Anterior
median
fissure
Anterior
funiculus
65
Functions of spinal cord
Conduct nerve impulses and serve as a
center for spinal reflexes
_____________carry sensory
information to the brain
_____________carry sensory
information from the brain to the
muscles and glands
9.14 The Brain
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Gyrus
Sulcus
Skull
Meninges
Cerebrum
Diencephalon
Corpus
callosum
Fornix
Midbrain
Brainstem
Pons
Medulla
oblongata
Cerebellum
Spinal cord
(a)
Fornix
Cerebrum
Midbrain
Pons
Corpus
callosum
Transverse fissure
Diencephalon
Cerebellum
Medulla oblongata
Spinal cord
(b)
© Martin M. Rotker/Photo Researchers, Inc.
67
Brain
• Major parts of the brain:
• Functions of the brain:
• Cerebrum
• Interprets sensations
• Frontal lobes
• Determines perception
• Parietal lobes
• Stores memory
• Occipital lobes
• Reasoning
• Temporal lobes
• Makes decisions
• Insula
• Coordinates muscular movements
• Diencephalon
• Regulates visceral activities
• Cerebellum
• Determines personality
• Brainstem
• Midbrain
• Pons
• Medulla oblongata
68
Structure of Cerebrum
Consists of two large masses (left and
right hemisphere), a deep bridge of
nerve fibers (__________), and a layer
of dura mater (_________)
Surface has many ridges (____) that are
separates by grooves (sulcus = ______,
fissure = _____)
Frontal Lobe
Forms the ______ portion of each
hemisphere
Bordered _______ by a central sulcus
Responsible for ________, ________,
_____________and _____________
Controls _________________
Parietal Lobe
________ to frontal lobe and
separated from it by the _________
Provide sensations of ________,
_____, ________, and ___________
Function in __________ and in
_______________________
Temporal Lobe
Lie ______ the frontal and parietal lobe
and is separated from them by a
___________
Responsible for ________
Interpret sensory experiences and
remember ________, _____, and other
_______________
Occipital Lobe
Forms __________________ and is
separated from the cerebellum by the
__________
Responsible for _______
Combine __________________
Insula (island)
Located deep within the _________
and is covered by parts of the frontal,
parietal and temporal lobes; ________
separates it from the lobes
Believed to be associated with the
_______ system as well
Functions of the Cerebrum
• Interpreting impulses
• Initiating voluntary movements
• Storing information as memory
• Retrieving stored information
• Reasoning
• Seat of intelligence and personality
76
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
Concentration, planning,
problem solving
Frontal eye field
Auditory area
Sensory areas involved with
cutaneous and other senses
Parietal lobe
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
Interpretation of auditory
patterns
Temporal lobe
Visual area
Cerebellum
Brainstem
77
Sensory Areas
• __________ sensory area
• Parietal lobe
• Interprets sensations on
skin
• Sensory area for _______
• Near base of the central sulcus
• Sensory area for ______
• Sensory ______ area
(____________)
• Temporal /parietal lobe
Motor areas involved with the control
• Usually left hemis.
of voluntary muscles
planning,
• Understanding and Concentration,
problem solving
formulating language
Frontal eye field
• Arises from centers deep within
the cerebrum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• ________ area
• Occipital lobe
• Interprets vision
• _______ area
• Temporal lobe
• Interprets hearing
Central sulcus
Sensory areas involved with
cutaneous and other senses
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
78
Sensory Areas
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Arm
Forearm
Trunk
Pelvis
Neck
Forearm Arm
Thigh
Trunk 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
79
Association Areas
• Regions that are not primary motor or primary sensory areas
• Widespread throughout the cerebral cortex
• Analyze and interpret sensory experiences
• Provide ________________________________________
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Central sulcus
Sensory areas involved with
cutaneous and other senses
Parietal lobe
Frontal eye field
Auditory area
Sensory speech area
( Wernicke’s area)
Front lobe
Occipital lobe
Combining visual images,
visual recognition of
objects
Motor speech area
(Broca’s area)
Lateral sulcus
Interpretation of auditory patterns
Visual area
Cerebellum
Temporal lobe
Brainstem
80
Association Areas
• ______ lobe association areas
• Concentrating
• Planning
• Complex problem solving
• ________ lobe association areas
• Interpret complex sensory
experiences
• Store memories of visual scenes,
music, and complex patterns
• _______ lobe association areas
• Understanding speech
• Choosing words to express
thought
• _______ lobe association areas
• Analyze and combine visual
images with other sensory
experiences
81
Motor Areas
• _______________
• Frontal lobes
• ___________
• _____________
• Anterior to primary motor
• Above Broca’s area
• Control voluntary muscles
cortex
• Usually in left hemisphere
• Controls muscles needed
for speech
• Controls voluntary movements
of eyes and eyelids
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Motor areas involved with the control
of voluntary muscles
Concentration, planning,
problem solving
Central sulcus
Sensory areas involved with
cutaneous and other senses
Parietal lobe
Frontal eye field
Auditory area
Sensory speech area
( Wernicke’s area)
Front lobe
Occipital lobe
Combining visual images,
visual recognition of
objects
Motor speech area
(Broca’s area)
Lateral sulcus
Interpretation of auditory patterns
Visual area
Cerebellum
Temporal lobe
Brainstem
82
Motor Areas
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Arm
Forearm
Thumb,
fingers,
and hand
Facial
expression
Trunk
Pelvis
Neck
Forearm Arm
Thigh
Trunk Pelvis
Thigh
Leg
Foot and
toes
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
83
Hemisphere Dominance
• The ______ hemisphere is dominant in most individuals
• _________ hemisphere controls:
• Speech
• Writing
• Reading
• Verbal skills
• Analytical skills
• Computational skills
• _____________ hemisphere controls:
• Nonverbal tasks
• Motor tasks
• Understanding and interpreting
musical and visual patterns
• Provides emotional and intuitive
thought processes
84
Basal Nuclei
• Also called basal ganglia
• Masses of gray matter
deep within cerebral
hemispheres
• Caudate nucleus,
putamen, and globus
pallidus
• Produce ________
• Control certain muscular
activities
• Primarily by
inhibiting motor
functions
•_________ disease
•_________ disease
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
85
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 ______________
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:
• _______ ventricles (2)
• Known as the first and
second ventricles
• ______ ventricle
• ______ ventricle
• Cerebral aqueduct
• Choroid plexuses
Interventricular
foramen
(a)
Lateral
ventricle
Third ventricle
Cerebral
aqueduct
Fourth
ventricle
(b)
To central canal
of spinal cord
86
Cerebrospinal Fluid
• Secreted by the ____________
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Circulates in ventricles, central Arachnoid
granulations
canal of spinal cord, and the
Choroid plexuses
subarachnoid space
of third ventricle
• Completely surrounds the brain Third ventricle
Cerebral aqueduct
and spinal cord
Fourth ventricle
• Excess or wasted CSF is
absorbed by the arachnoid
granulations
• Clear fluid
• Volume is about __________.
• Nutritive and protective
• Helps maintain stable ion
concentrations in the CNS
Blood-filled
dural sinus
Pia mater
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
87
Diencephalon (limbic system)
• Between _______________ and above the __________
• Surrounds the _______ ventricle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Thalamus
• Hypothalamus
• Optic tracts
• Optic chiasma
• Infundibulum
• Posterior pituitary
• Mammillary bodies
• Pineal gland
Superior
colliculus
Corpora quadrigemina
Optic nerve
Optic chiasma
Inferior
colliculus
Pituitary gland
Mammillary body
Optic tract
Pons
Thalamus
Third
ventricle
Cerebral
peduncles
Pyramidal tract
Olive
Pineal gland
Fourth
ventricle
Cerebellar
peduncles
Medulla
oblongata
Spinal cord
(a)
(b)
88
Diencephalon
The Limbic System
• Consists of:
• Functions:
• Portions of frontal lobe
• Controls emotions
• Portions of temporal lobe
• Produces feelings
• Hypothalamus
• Interprets sensory impulses
• Thalamus
• Basal nuclei
• Other deep nuclei
90
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
91
Midbrain
• Between ________ and
______
• Contains bundles of fibers
that join lower parts of
brainstem and spinal cord
with higher part of brain
•Masses of gray matter that
serve as reflex centers –
(_____________)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
colliculus
Corpora quadrigemina
Optic nerve
Optic chiasma
Inferior
colliculus
Pituitary gland
Mammillary body
Optic tract
Pons
Thalamus
Third
ventricle
Cerebral
peduncles
Pyramidal tract
Olive
Pineal gland
Fourth
ventricle
Cerebellar
peduncles
Medulla
oblongata
Spinal cord
(a)
(b)
92
Pons
• Rounded bulge on
underside of brainstem
• Between __________ and
________
•________________
• Relays nerve impulses to
and from medulla
oblongata and cerebellum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
colliculus
Corpora quadrigemina
Optic nerve
Optic chiasma
Inferior
colliculus
Pituitary gland
Mammillary body
Optic tract
Pons
Thalamus
Third
ventricle
Cerebral
peduncles
Pyramidal tract
Olive
Pineal gland
Fourth
ventricle
Cerebellar
peduncles
Medulla
oblongata
Spinal cord
(a)
(b)
93
Medulla Oblongata
• Enlarged continuation of
spinal cord
• Conducts ascending and
descending impulses between
brain and spinal cord
• Contains
______________________
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
colliculus
Corpora quadrigemina
Optic nerve
Inferior
colliculus
Pituitary gland
Mammillary body
Optic tract
Pons
• Contains various nonvital
reflex control centers
(___________________)
Optic chiasma
Thalamus
Third
ventricle
Cerebral
peduncles
Pyramidal tract
Olive
Pineal gland
Fourth
ventricle
Cerebellar
peduncles
Medulla
oblongata
Spinal cord
(a)
(b)
94
Cerebellum
• Inferior to occipital lobes
• Posterior to pons and medulla Longitudinal
fissure
oblongata
• Two hemispheres
Thalamus
• Vermis connects hemispheres
Superior
• __________ (gray matter) – thin
peduncle
layer surrounding Arbor vitae
Pons
Middle
peduncle
• _________ (white matter) – primary
Inferior peduncle
substance
Medulla oblongata
• Cerebellar peduncles (nerve fiber
tracts) – communication
•Integrates _______ information
concerning position of body parts
• Coordinates ______ muscle activity
• Maintains _______
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Corpus callosum
Cerebellum
96
Quiz 3
9.15: Peripheral Nervous System
• __________ nerves (12 pairs) arising from the brain
• Somatic fibers connecting to the skin and skeletal muscles
• Autonomic fibers connecting to viscera
• __________ nerves arising from the spinal cord
• Somatic fibers connecting to the skin and skeletal muscles
• Autonomic fibers connecting to viscera
98
Nervous System Subdivisions
Pge 258
99
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)
100
Cranial Nerves I and II
• _________ nerve (I)
• Sensory nerve
• Fibers transmit impulses
associated with smell
•Located in the lining of the
upper nasal cavity
• ______ nerve (II)
• Sensory nerve
• Fibers transmit impulses
associated with vision
•Sensory nerve cell bodies of
these nerve fibers are in
ganglion cell layers within
the eyes
101
Cranial Nerves III and IV
• _________ nerve (III)
• Primarily motor nerve
• Motor impulses to muscles
that:
• Raise eyelids
• Move the eyes
• Focus lens
• Adjust light entering eye
• _________ nerve (IV)
• Primarily motor nerve
• Motor impulses to muscles
that move the eyes
• Some sensory
• Proprioceptors
• Some sensory
• Proprioceptors
102
Cranial Nerve V
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• __________ nerve (V)
•
Largest cranial nerves
• Mixed nerve
• (1) Ophthalmic division
• Sensory from surface of eyes,
tear glands, scalp, forehead, and
upper eyelids
• (2) Maxillary division
• Sensory from upper teeth,
upper gum, upper lip, palate,
and skin of face
• (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
Lacrimal nerve
Ophthalmic
division
Lacrimal
gland
Eye
Maxillary
division
Infraorbital
nerve
Mandibular
division
Maxilla
Lingual
nerve
Inferior
alveolar
nerve
Tongue
Mental
nerve
Mandible
103
Cranial Nerves VI and VII
• ________ nerve (VI)
• Primarily motor nerve
• Motor impulses to muscles
that move the eyes
• Some sensory
•Proprioceptors
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Temporal nerve
Zygomatic nerve
Buccal nerve
• _______ nerve (VII)
Facial nerve
• Mixed nerve
• Sensory from taste receptors Posterior auricular
• Motor to muscles of facial nerve
expression, tear glands, and Parotid salivary
gland
salivary glands
Mandibular nerve
Cervical nerve
68
104
Cranial Nerves VIII and IX
• __________ nerve (VIII)
• _____________ nerve (IX)
• Acoustic or auditory nerve
• Mixed nerve
• Sensory nerve
• Sensory from pharynx, tonsils,
• Two (2) branches:
tongue and carotid arteries
• Vestibular branch
• Motor to salivary glands and
• Sensory from equilibrium
muscles of pharynx
receptors of ear
• Cochlear branch
• Sensory from hearing
receptors
105
Cranial Nerve X
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• ________ nerve (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
Palate
Superior laryngeal
nerve
Superior ganglion
of vagus nerve
Inferior ganglion
of vagus nerve
Nerve XI
Nerve XII
Carotid body
Recurrent laryngeal
nerve
Left vagus
nerve
Cardiac nerves
Lung
Heart
Stomach
Liver
Spleen
Pancreas
Kidney
Small
intestine
Large intestine
106
Cranial Nerves XI and XII
• ________ nerve (XI)
• _________ nerve (XII)
• Primarily motor
• Primarily motor nerve
• Motor to muscles of the
• We called this “Spinal”
tongue (speaking, chewing,
Accessory because:
swallowing)
• Cranial branch
• Some sensory
• Motor to muscles of
• Proprioceptor
soft palate, pharynx
and larynx
• Spinal branch
• Motor to muscles of
neck and back
• Some sensory
• Proprioceptor
107
Spinal Nerves
• 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)
• Cauda equina
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
C1
C2
C3
C4
C5
C6
C7
C8
T1
T2
T3
T4
T5
T6
T7
Posterior
view
Cervical
nerves
Thoracic
nerves
T8
T9
T10
T11
Cauda equina
T12
L1
L2
L3
L4
L5
S1
S2
S3
S4
S5
Co
Lumbar
nerves
Sacral
nerves
Coccygeal
nerve
108
Spinal Nerves
• ___________________
• Sensory root
• Dorsal root ganglion
• Cell bodies of
sensory neurons
whose axons conduct
impulses inward from
peripheral body parts
•___________________
• 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 branch
of spinal nerve
Ventral branch
of spinal nerve
Dorsal root
ganglion
Ventral root
Dorsal root
Posterior
median sulcus
Paravertebral
ganglion
Posterior
horn
(b)
Lateral horn
Anterior
horn
Central
canal
Anterior
median fissure
Ventral root
(a)
Visceral branch
of spinal nerve
Ventral branch
of spinal nerve (ventral ramus)
Dorsal branch
of spinal nerve (dorsal ramus)
Spinal nerve
Paravertebral
ganglion
Visceral branch
of spinal nerve
109
Nerve Plexuses
• Nerve plexus
• Complex networks formed by anterior branches of spinal
nerves – they innervate particular regions of the body
• The fibers of various spinal nerves are sorted and recombined
• There are three (3) nerve plexuses:
• (1) ________ plexus
• Formed by anterior branches of C1-C4 spinal nerves
• Lies deep in the neck
• Supply to muscles and skin of the neck
• C3-C4-C5 nerve roots contribute to muscle fibers of
diaphragm
110
Brachial Plexus
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• (2) ________
plexus
• Formed by anterior
branches C5-T1
• Lies deep within shoulders
• Five (5) branches:
Ventral rami: C5, C6, C7, C8, T1
Trunks: upper, middle, lower
Anterior divisions
Posterior divisions
Dorsal
scapular n.
Suprascapular n.
Lateral pectoral n.
Medial pectoral n.
Lower subscapular n.
Thoracodorsal n.
Musculocutaneous n.
• 1. Musculocutaneous nerve
•2.
•3.
•4.
•5.
Ulnar and
Median nerves
Radial nerve
Axillary nerve
C5
C6
C6
C7
Axillary n.
C8
Humerus
T1
Median n.
Ulnar n.
Axillary n.
Radial n.
(a)
C7
C8
T1
C5
Median n.
Musculocutaneous n.
Radial n.
Ulnar n.
Ulna
Radius
(b)
111
Lumbosacral Plexus
• (3) ______________ plexus
• Formed by the anterior
branches of L1-S5 roots
• Can be a lumbar (L1-L5)
plexus and a sacral (S1-S5)
Lateral
plexus
femoral
cutaneous n.
• Extends from lumbar region
Femoral n.
Obturator
n.
into pelvic cavity
Superior
gluteal n.
•3 major branches
Inferior
gluteal n.
• ________ nerve
Common
Sciatic n. fibular
• ________ nerve
(peroneal) n.
Tibial n.
•________ nerve
Pudendal n.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Ventral
rami
Anterior
divisions
Posterior
divisions
(a)
Superior
gluteal n.
L1
L2
Obturator n.
Inferior
gluteal n.
L3
Sacral
plexus
Femoral n.
L4
Sciatic n.
Pudendal n.
Posterior
cutaneous n.
Saphenous n.
L5
Common
fibular
(peroneal) n.
S1
S2
S3
S4
Tibial n.
S5
(b)
(c)
•Anterior branches do not enter
a plexus, instead they become
intercostal nerves
112
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
Cauda equina
Femoral
nerve
Obturator nerve
Sciatic nerve
C1
C2
C3
C4
C5
C6
C7
C8
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
L2
L3
L4
L5
S1
S2
S3
S4
S5
Co
Cervical plexus
(C1–C4)
Brachial plexus
(C5–T1)
Intercostal
nerves
Lumbosacral plexus
(T12–S5)
113
9.16: Autonomic Nervous System
• Functions without conscious effort
• Controls visceral activities
• Regulates smooth muscle, cardiac muscle, and glands
•2 Divisions
• _____________ NS – (speeds up) prepares the body for
energy-expending, stressful, or emergency situations as
part of “fight-or-flight” response
• _____________ NS – (slows down) most active under
ordinary, restful conditions and counterbalances the effect
of the sympathetic NS
114
Autonomic Nerve Fibers
• All of the neurons are
_____________
• ___________ fibers
• Axons of preganglionic
neurons
• Neuron cell bodies in
brain
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Interneurons
Dorsal root ganglion
Dorsal root
ganglion
Sensory
neuron
Sensory
neuron
Spinal cord
Autonomic
ganglion
Preganglionic
fiber
Somatic motor neuron
Postganglionic
fiber
Viscera
• _____________ fibers
• Axons of postganglionic
(a) Autonomic pathway
neurons
• Neuron cell bodies in
ganglia
• Extend to visceral effector
Skin
Skeletal
muscle
(b) Somatic pathway
116
Sympathetic Division
Pge 264
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Lacrimal gland
Eye
Parotid gland,
submandibular and
sublingual glands
Blood vessels
Heart
Celiac and
pulmonary
plexuses
Celiac
ganglion
Skin
Fibers to
skin, blood vessels,
and adipose tissue
Superior
mesenteric
ganglion
Trachea
Lungs
Liver
Gallbladder
Stomach
Pancreas
Small intestine
Spinal
cord
Inferior
mesenteric
ganglion
Sympathetic
chain ganglia
Large intestine
Adrenal gland
Kidney
Urinary
bladder
Ovary
Uterus
Preganglionic Postganglionic
neuron
neuron
Penis
Scrotum
117
Parasympathetic Division
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Sphenopalatine
ganglion
Pge 265
Cranial
nerve III
Ciliary ganglion
Submandibular
Cranial
ganglion
Nerve VII
Cranial Otic ganglion
nerve IX
Cranial nerve X
(Vagus)
Lacrimal
gland
Eye
Submandibular
and sublingual glands
Parotid
gland
Heart
Trachea
Lung
Cardiac and
pulmonary
plexuses
Liver
Gallbladder
Stomach
Spleen
Pancreas
Celiac
plexus
Superior
hypogastric
plexus
Spinal
cord
Small intestine
Inferior
hypogastric
plexus
Large intestine
Kidney
Pelvic
nerves
Preganglionic Postganglionic
neuron
neuron
Scrotum
Penis
Urinary
bladder
Uterus
Ovary
118
Autonomic Neurotransmitters
• ___________ fibers
• Release acetylcholine
• Preganglionic
sympathetic and
parasympathetic fibers
• Postganglionic
parasympathetic fibers
• __________ fibers
• Release
norepinephrine
• Most
postganglionic
sympathetic
fibers
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
ACh = acetylcholine (cholinergic)
Brain
NE = norepinephrine (adrenergic)
Visceral
effectors
Cranial
parasympathetic
neurons
Preganglionic fiber (axon)
ACh
Ganglion
ACh
Sympathetic neurons
ACh
Postganglionic fiber (axon)
NE
Paravertebral
ganglion
ACh
NE
Collateral
ganglion
Sacral
parasympathetic
neurons
ACh ACh
Page 266
119
Control of Autonomic Activity
• Controlled largely by CNS
• Medulla oblongata regulates ____________________
activities
• Hypothalamus regulates visceral functions,
_______________________________________________
• Limbic system and cerebral cortex control emotional
responses
120
Quiz 4