1. © 2016 Pearson Education, Inc.

2. I. Functions and Divisions of Nervous System
A. Nervous system is master controlling and communicating system of body 1. Cells communicate via electrical and chemical signals a. Rapid and specific b. Usually cause almost immediate responses
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3. B. Nervous system has three overlapping functions Sensory input
a. Information gathered by sensory receptors about internal and external changes
Integration
a. Processing and interpretation of sensory input
Motor output
a. Activation of effector organs (muscles and glands) produces a response
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4. Figure 11.1 The nervous system’s functions.
Sensory input
Integration
Motor output
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5. C. Nervous system is divided into two principal parts: 1
C. Nervous system is divided into two principal parts: 1. Central nervous system (CNS) a. Brain and spinal cord of dorsal body cavity b. Integration and control center i. Interprets sensory input and dictates motor output
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6. 2. Peripheral nervous system (PNS)
a. The portion of nervous system outside CNS
b. Consists mainly of nerves that extend from brain and spinal cord
i. Spinal nerves to and from spinal cord
ii. Cranial nerves to and from brain
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7. Figure 11.2 The nervous system.
Central nervous
system (CNS)
Peripheral nervous
system (PNS)
Brain
Cranial nerves
Spinal cord
Spinal nerves
Ganglia
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8. D. Peripheral nervous system (PNS) has two functional divisions 1
D. Peripheral nervous system (PNS) has two functional divisions 1. Sensory (afferent) division a. Transmit sensory impulses to the CNS 2. Motor (efferent) division a. Transmit action impulses from the CNS b. Two divisions i. Somatic nervous system ii. Autonomic nervous system
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9. E. Motor Divisions 1. Somatic nervous system a
E. Motor Divisions 1. Somatic nervous system a. Voluntary nervous system i. Conscious control of skeletal muscles 2. Autonomic nervous system a. Involuntary nervous system b. Two functional subdivisions i. Sympathetic – “Fight or Flight” ii. Parasympathetic – “Rest and Digest”
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10. Figure 11.3 Organization of the nervous system.
Central nervous system (CNS)
Peripheral nervous system (PNS)
Brain and spinal cord
Cranial nerves and spinal nerves
Integrative and control centers
Communication lines between the CNS
and the rest of the body
Sensory (afferent) division
Motor (efferent) division
Somatic and visceral sensory
nerve fibers
Motor nerve fibers
Conducts impulses from the CNS
to effectors (muscles and glands)
Conducts impulses from
receptors to the CNS
Somatic nervous
system
Autonomic nervous
system (ANS)
Somatic motor
(voluntary)
Visceral motor
(involuntary)
Conducts impulses
from the CNS to
skeletal muscles
Conducts impulses
from the CNS to
cardiac muscle,
smooth muscle,
and glands
Sympathetic division
Parasympathetic
division
Mobilizes body systems
during activity
Conserves energy
Promotes house-
keeping functions
during rest
Structure
Function
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11. Bell Ringer
6.01 What part(s) of the body make up the nervous system? 6.02 What are the 3 functions of the nervous system?
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12. II. Neuroglia
A. Nervous tissue consists of two principal cell types 1. Neuroglia (glial cells): small cells that surround and wrap delicate neurons 2. Neurons (nerve cells): excitable cells that transmit electrical signals
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13. B. Four main neuroglia support CNS neurons 1. Astrocytes a
B. Four main neuroglia support CNS neurons 1. Astrocytes a. Most abundant, versatile, and highly branched of glial cells b. Cling to neurons, synaptic endings, and capillaries i. Transport nutrients from blood capillaries to the neurons
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14. Astrocytes are the most abundant CNS neuroglia.
Figure 11.4a Neuroglia.
Capillary
Neuron
Astrocyte
Astrocytes are the most
abundant CNS neuroglia.
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15. 2. Microglial cells a. Small, ovoid cells with thorny processes that touch and monitor neurons b. Migrate toward injured neurons c. Can transform to kill microorganisms and dispose of neuronal debris
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16. Microglial cells are defensive cells in the CNS.
Figure 11.4b Neuroglia.
Neuron
Microglial
cell
Microglial cells are defensive
cells in the CNS.
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17. 3. Ependymal cells a. Line the central cavities of the brain and spinal column b. Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue fluid bathing CNS cells
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18. Ependymal cells line cerebrospinal fluid–filled cavities.
Figure 11.4c Neuroglia.
Cilia
Fluid-filled cavity
Ependymal
cells
Brain or
spinal cord
tissue
Ependymal cells line cerebrospinal
fluid–filled cavities.
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19. 4. Oligodendrocytes a. Branched cells
b. Processes wrap CNS nerve fibers, forming insulating myelin sheaths in thicker nerve fibers
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20. Oligodendrocytes have processes that form myelin sheaths around CNS
Figure 11.4d Neuroglia.
Myelin sheath
Process of
oligodendrocyte
Nerve
fibers
Oligodendrocytes have processes
that form myelin sheaths around CNS
nerve fibers.
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21. C. Two major neuroglia seen in PNS 1. Satellite cells a
C. Two major neuroglia seen in PNS 1. Satellite cells a. Surround neuron cell bodies in PNS b. Function similar to astrocytes of CNS 2. Schwann cells a. Similar function as oligodendrocytes b. Vital to regeneration of damaged peripheral nerve fibers
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22. (forming myelin sheath)
Figure 11.4e Neuroglia.
Cell body of neuron
Satellite
cells
Schwann cells
(forming myelin sheath)
Nerve fiber
Satellite cells and Schwann cells (which
form myelin) surround neurons in the PNS.
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23. Bell Ringer
6.03 What are the two categories of cells that make up nervous tissue? 6.04 Identify the two neuroglial cell types that produce myelin and state where they are found (CNS or PNS).
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24. III. Neurons
A. Neurons (nerve cells) are structural units of nervous system 1. All have cell body and one or more processes a. Most neuron cell bodies are located in CNS i. Nuclei: clusters of neuron cell bodies in CNS ii. Ganglia: clusters of neuron cell bodies in PNS
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25. 2. Two types of processes a. Dendrites b. Axon 3. Tracts a
2. Two types of processes a. Dendrites b. Axon 3. Tracts a. Bundles of neuron processes in CNS 4. Nerves a. Bundles of neuron processes in PNS
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26. Figure 11.5a Structure of a motor neuron.
Dendrites
(receptive
regions)
Cell body
(biosynthetic center
and receptive region)
Nucleus
Axon
(impulse-generating
and conducting
region)
Nucleolus
Myelin sheath gap
(node of Ranvier)
Chromatophilic
substance (rough
endoplasmic
reticulum)
Axon terminals
(secretory
region)
Axon
hillock
Schwann
cell
Impulse
direction
Terminal
branches
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27. B. Structure of a Neuron 1. Dendrites a
B. Structure of a Neuron 1. Dendrites a. Receptive (input) region of neuron b. Convey incoming messages toward cell body
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28. Figure 11.5b Structure of a motor neuron.
cell body
Dendritic
spine
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29. 2. The axon a. Long axons are called nerve fibers b
2. The axon a. Long axons are called nerve fibers b. Axon is the conducting region of neuron c. Generates nerve impulses and transmits them to axon terminal d. Carries on many conversations with different neurons at same time
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30. 3. Myelin sheath a. Protect and electrically insulate axon b
3. Myelin sheath a. Protect and electrically insulate axon b. Increase speed of nerve impulse transmission
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31. Figure 11.6a PNS nerve fiber myelination.
Schwann
cell plasma
membrane
Schwann cell
cytoplasm
A Schwann cell
envelops an axon. 1
Axon
Schwann cell
nucleus 2
The Schwann cell
then rotates around
the axon, wrapping
its plasma membrane loosely around it in successive layers.
The Schwann cell cytoplasm is forced
from between the membranes. The tight membrane wrappings surrounding the axon form the myelin sheath. 3
Myelin
sheath
Schwann cell
cytoplasm
Myelination of a nerve fiber (axon)
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32. Figure 11.6b PNS nerve fiber myelination.
Myelin sheath
Outer collar
of perinuclear
cytoplasm
(of Schwann
cell)
Axon
Cross-sectional view of a myelinated axon
(electron micrograph 24,000×)
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33. 4. Myelin Sheath Gaps a. Gaps between adjacent Schwann cells b
4. Myelin Sheath Gaps a. Gaps between adjacent Schwann cells b. Formerly called Nodes of Ranvier
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34. b. Can excite or inhibit neurons it contacts
5. Axon Terminals
a. Terminal: region that secretes neurotransmitters, which are released into extracellular space
b. Can excite or inhibit neurons it contacts
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35. Figure 11.5a Structure of a motor neuron.
Dendrites
(receptive
regions)
Cell body
(biosynthetic center
and receptive region)
Nucleus
Axon
(impulse-generating
and conducting
region)
Nucleolus
Myelin sheath gap
(node of Ranvier)
Chromatophilic
substance (rough
endoplasmic
reticulum)
Axon terminals
(secretory
region)
Axon
hillock
Schwann
cell
Impulse
direction
Terminal
branches
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36. Oligodendrocytes have processes that form myelin sheaths around CNS
Figure 11.4d Neuroglia.
Myelin sheath
Process of
oligodendrocyte
Nerve
fibers
Oligodendrocytes have processes
that form myelin sheaths around CNS
nerve fibers.
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37. C. Classification of Neurons 1. Structural - number of processes
a. Multipolar: three or more processes
i.One axon
ii. others dendrites
b. Bipolar: two processes
i. one axon
ii. one dendrite
c. Unipolar: one process
Some may only have one axon
Some may split into two axons
Called “Pseudounipolar”
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38. Table 11.1-1 Comparison of Structural Classes of Neurons
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39. Table 11.1-2 Comparison of Structural Classes of Neurons (continued)
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40. 2. Functional - direction in which nerve impulse travels a. Sensory i
2. Functional - direction in which nerve impulse travels a. Sensory i. Transmit impulses from sensory receptors toward CNS b. Motor i. Carry impulses from CNS to effectors c. Interneurons i. Lie between motor and sensory neurons ii. Most are entirely within CNS
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41. Table 11.1-3 Comparison of Structural Classes of Neurons (continued)
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42. Bell Ringer
6.05 What part of a neuron conducts impulses/action potentials? 6.06 What type of neuron sends impulses toward the CNS?
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43. IV. The Brain
Anatomy of the Cerebrum
Cerebral Hemispheres
Surface markings
i. Gyrus: ridge
ii. Sulcus: shallow groove

44. iii. Fissure: deep groove
Longitudinal Fissure
separates cerebral hemispheres
Transverse Fissure
Separates cerebrum from cerebellum

46. b. Regions:
i. Cerebral cortex of gray matter superficially
ii. White matter internally
Contains the Corpus Callosum
Major nerve that connects cerebral hemispheres for communication
iii. Basal nuclei deep within white matter

48. 2. Lobes a. Frontal i. Primary motor area b. Parietal i
2. Lobes a. Frontal i. Primary motor area b. Parietal i. Primary sensory area c. Temporal i. Auditory area d. Occipital i. Visual area

50. 3. The Diencephalon a. Thalamus i
3. The Diencephalon a. Thalamus i. Main function is to act as relay station for incoming information ii. Sorts, edits and relays ascending input iii. Overall, it acts to mediate sensation, motor activities, learning and memory

51. b. Hypothalamus
i. Located below thalamus
ii. Main visceral control and regulating center that is vital to homeostasis

53. B. The Brain Stem 1. Midbrain a
B. The Brain Stem 1. Midbrain a. Located between diencephalon and pons b. Contains large nerve fibers that serve as reflex centers i. Visual reflex center ii. Auditory reflex center

54. 2. Pons
a. Located between midbrain & medulla oblongata
b. means “bridge”
c. involved with control of breathing

55. 3. Medulla Oblongata
a. merges with the spinal cord
b. contains several control centers
i. heart rate
ii. Blood pressure
iii. Breathing
iv. Swallowing
v. vomiting

58. C. The Cerebellum 1. “Little Brain” 2
C. The Cerebellum 1. “Little Brain” 2. Located on the bottom of occipital lobe a. divided into two hemispheres b. contains gray cortex on the outside c. white cortex in the center

59. 3. Involved with balance & movement
a. ensures that skeletal muscle movements are smooth and precise
b. controls balance and equilibrium

60. Bell Ringer
6.07 Which part of the brain acts as a “relay station” for incoming information? 6.08 What part of the brain is responsible for visual and auditory reflexes?
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61. V. The Spinal Cord
A. Enclosed in the vertebral column 1. Actually ends just below the ribs a. L1 or L2 Vertebra

62. B. Functions
1. Provides two-way communication to and from brain and body
2. Major reflex center
a. reflexes are initiated and completed at spinal cord

63. C. Spinal Nerves
1. 31 pairs nerves that are part of PNS
a. Nerves serving upper and lower limbs emerge here
2. “Cauda Equina”
a. Means “Horse Tail”
b. Collection of nerve roots at inferior end of vertebral canal

66. D. Spinal Nerve Roots 1. Every spinal nerve connects to the spinal cord in two places a. connections are called “roots” b. Connect to the front and back side 2. Dorsal Roots a. “Back” roots b. Beginning of Sensory Neurons 3. Ventral Roots a. “Front” roots b. Beginning of Motor Neurons

68. Bell Ringer
6.09 What does “Cauda Equina” mean? 6.10 What type of spinal roots are connected to motor neurons?
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69. VI. Protection of Brain and Spinal Cord
Meninges
1. Cover and protect the CNS
2. Consists of three layers
a. Dura Mater
i. Outermost layer
ii. Very tough

71. b. Arachnoid Mater
i. middle layer
ii. Web-like
c. Pia Mater
i. Inner layer
ii. Thinnest
iii. Clings to the brain and spinal cord

73. B. Cerebrospinal Fluid (CSF) 1
B. Cerebrospinal Fluid (CSF) 1. Forms a liquid cushion of constant volume around brain and spinal cord a. Watery fluid b. Made from blood plasma i. Helps nourish brain and carry chemical signals 2. Continually moving a. Forms and drains at a constant rate b. Specific pressure is maintained

75. 3. Lumbar (Spinal) Puncture or Tap
a. Used when testing for diseases that affect the CSF
i. CSF is withdrawn from the lower spine
b. Changes pressure
i. patients to remain laying down for hours after the procedure
ii. Can result in an extremely painful “spinal headache”

77. C. Blood Brain Barrier 1. Helps maintain stable environment for brain a. Exceptionally impermeable tight junctions keep brain separated from many bloodborne substances

78. 2. Barrier is selective, but not absolute
a. Allows certain nutients to move by facilitated diffusion
b. Metabolic wastes, proteins, toxins, most drugs, small nonessential amino acids, K+ denied
i. Allows any fat-soluble substances to pass, including alcohol, nicotine and anesthetics

79. Cranial Nerves
Create flashcards for the 12 Cranial Nerves Be sure to include the Roman Numeral, it’s important!!!

80. I. Olfactory - Sense of smell II. Optic – Sense of vision III
I. Olfactory - Sense of smell II. Optic – Sense of vision III. Oculomotor – Movement of eyelids IV. Trochlear – Movement of eyes up and down

81. V. Trigeminal – Sense of touch on the face; movement of jaw for chewing VI. Abducens – Movement of eyes side to side VII. Facial – Movement of facial muscles (facial expression) VIII. Vestibulocochlear – Sense of balance and hearing

82. IX. Glossopharyngeal - Movement of pharynx for swallowing; sense of taste X. Vagus – Movement of digestive organs XI. Accessory – Movement of neck and shoulders XII. Hypoglossal – Movement of tongue