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The Nervous System
Lesson 1:
An Overview
Upon completion of this lesson, students
should be able to …
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List the functions of the nervous system.
Identify and discuss the structures that make
up the central nervous system.
Explain how nerve impulses are transmitted.
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State the functions of the peripheral nervous
system, the somatic nervous system and the
autonomic nervous system, and distinguish
the differences between each.
Explain the delicate balance between the
sympathetic and parasympathetic nervous
systems.
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Central Nervous System (CNS)
◦ Brain
◦ Spinal Cord
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Peripheral Nervous System (PNS)
◦ Peripheral nerves
◦ Cranial nerves
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PNS receives
sensory information
Information goes to
the CNS
The CNS tells the
PNS to carry out
movement and
body functions
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Control body’s functions
impulse is transmitted from the neural cell
body to muscle or organ
Usually have several dendrites and only one
axon.
covered with fatty insulating
substance
 myelin sheath
 Myelin increases the speed at which
impulses are transmitted along the
axon.
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Axons may be several feet long
 Dendrites resemble tree branches and
are unsheathed
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 Lack
true dendrites,
 Sheathed
 resemble axons
Motor Neuron
Sensory Neuron
 Transmit
impulses to the CNS.
 CNS activates motor neurons
 Respond to sensory information.
located entirely within the CNS
 Work between sensory and motor
neurons
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Myelinated sheaths
◦ inner sheath of myelin
◦ outer sheath of Schwann cells
◦ Schwann cells are needed for regenerating
a damaged nerve
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Unmyelinated sheaths
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bundled unit of fibers
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Group of nerve fibers in CNS
The spinal cord
◦ Afferent =ascend to the brain
◦ Efferent = descend from the brain
The Brain
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largest nerve tract is corpus callosum
joins the right and left hemispheres
Solely comprised
of the brain and
spinal cord.
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Parts of the brain
 Largest
mass of nervous tissue
 Three meninges:
◦ Pia Mater
◦ Arachnoid
◦ Dura Mater
Controls body functions and
movement
 specific areas of the brain
 Generates thought
 memory and emotion
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REPORT ON REPORTER
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Largest part of brain
Controls higher thought processes
Outer layer is cerebral cortex
left and right halves called cerebral
hemispheres
 has
four lobes
 Stores
memories and creates
emotions
Contains
◦ midbrain
◦ pons
◦ medulla oblongata (Connects brain
[pons] to spinal cord)
 Relay information
◦ visual
◦ auditory
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Located in the back of the skull
 Second largest portion of the brain
 Coordinates voluntary and involuntary
movement
 Adjusts muscles to maintain posture
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Label and color the brain
Connects the brain with the peripheral
nerves
 surrounded by cerebrospinal fluid
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encased in the
vertebral column
(backbone)
 four divisions:
cervical, thoracic,
lumbar, and
sacral
 Spinal nerves exit
through foramina
(openings)
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1.
What do you think is the purpose
of cerebrospinal fluid?
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Circulates around the brain and spinal cord
Provides cushioning and protection
Contains nourishment
Contains neurotransmitters
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http://www.raptorpharma.com/science_neur
otrans.html
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12 pairs of
cranial nerves
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Olfactory – provides sense of smell
Optic – provides vision
Trigeminal –sensory input from the face
Facial – controls the muscles of the face
and scalp
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Vestibulocochlear–hearing and
equilibrium
Glossopharyngeal – provides general
sense of taste
Vagus – controls muscles of the
digestive, slowing of heartbeat
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Pair up
Different stations
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Responsible for controlling involuntary
bodily functions
divides
◦ sympathetic
◦ parasympathetic
 fight
or flight
◦ increased alertness
◦ Increase metabolic rate
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the adrenal gland releases epinephrine
that causes adrenaline rush
 conserve
energy
 innervate the digestive system
 decrease in metabolism
 Decrease in bodily functions
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Impulses are transmitted between
neurons via chemicals called
neurotransmitters
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Anesthesiologist
Neurologist
Neurosurgeon
Psychiatrist
Psychologist