NERVOUS SYSTEM.pdf NERVOUS SYSTEM NERVOUS SYSTEM.pdf
NERVOUS SYSTEM 5
Chapter Outline
Structure & Function
The Neuron
The Central Nervous System
The Peripheral Nervous System
Combining Forms
Abbreviations
Pathologies
Procedures & Pharmacology
Common Diagnostic Tests & Procedures
Pharmacology
Case Study: Shingles
Chapter Practice Exercises
PREFIX & SUFFIX REVIEW
Study these Ch. 2 prefixes & suffixes; they are used often in medical terms for the nervous system. Be sure to read the Learning Tips throughout the
Ch. to find study suggestions that match your learning preferences!
Prefixes Suffixes
a- without, not, absence of -al, -ic, -tic pertaining to -metry measurement
dys- abnormal, bad, painful, difficult -algia, dynia pain -ology study of
hyper- excessive, above -cele hernia -oma tumor
iso- same, equal -ectomy excision, surgical removal -osis abnormal condition
macro- large -genesis, -genic creating, producing -pathy disease
micro- small -ia condition -plasia formation, growth
para- beside, near -itis inflammation -rrhaphy suture, suturing
poly- much -kinesis movement -tomy cutting into, incision
-lysis destruction -tripsy crushing
-malacia softening -trophy nourishment, growth
-megaly enlargement -uria urine
Flashpoint
Your brain is something like a very complex computer with infinite data-storage capabilities.
Structure & Function
The nervous system receives information from the external environment as well as from the internal body to communicate &
coordinate your everyday functions. It plays a key role in maintaining homeostasis (home/o = same, -stasis = stopping), the state
of dynamic equilibrium in the internal environment of the body. More complex than the most advanced computer, the nervous
system is capable of storing vast amounts of data as well as receiving & sending thousands of messages throughout the body
instantly & simultaneously.
While the nervous system functions as a total system, you may find it more easily understood if we divide it into its two major
parts: CNS & the PNS. However, we first begin by looking at the most essential element: the neuron.
The Neuron
A nerve cell, known as a neuron, is illustrated in Fig. 5-1. Neurons vary in size & shape, but they all have the following key parts:
cell body, axon, & dendrites. The cell body houses the nucleus & other microscopic structures that keep the cell energized &
functioning. The dendrites, which resemble the branches of a tree, are responsible for receiving information from the internal &
external environment & bringing this information to the cell body. The axon sends electrical signals, or impulses, to other cells.
The axon may be short or quite long & is often coated in a protective layer called the myelin sheath. Myelin is a fatty substance that
also helps to increase the speed of nerve impulses from one axon to another. In diseases such as multiple sclerosis, the myelin
sheath is damaged, which slows down the impulses or prevents them from reaching their destination.
FIG. 5-1 Neurons contain a cell body, axon, &
dendrites. The gaps Bet. the axons &
dendrites of two neurons are synapses.
A nerve cell in the human body functions somewhat like an electrical cord in your home. In an electrical cord, the wires
are protected by a rubber coating of insulation; so too, your nerves are protected by the myelin sheath. The electrical cord sends
electricity from the energy source to the refrigerator,NERVOUS
NERVOUS SYSTEM
television, or other device so that it can operate. Your
SYSTEM.pdf
nerve cells send
NERVOUS SYSTEM.pdf
,NERVOUS SYSTEM.pdf NERVOUS SYSTEM NERVOUS SYSTEM.pdf
electrical impulses down t axon to muscles, organs, or other tissues in the periphery so that they can function. When the insulating
layer of an electrical extension cord becomes frayed or otherwise damaged, the cord may “short out”; as a result, signal
transmission may be temporarily or permanently lost, & the device may no longer work. Similarly, if the myelin sheath on the axon
degenerates or is damaged, the electrical impulse may be temporarily or permanently lost. As a result, the organ or muscle that it
innervates may not function properly. This explains some of the symptoms caused by degenerative neuromuscular diseases such as
multiple sclerosis.
Learning Tip
Use the illustrations by tracing them with your fingertip, naming the various parts aloud, & describing their functions as you do so. This is
useful for visual, auditory, verbal, & kinesthetic learners.
The Central Nervous System
CNS comprises the brain & spinal cord (Fig. 5-2). CNS is where data storage & information processing occurs. The brain comprises
three major divisions: the cerebrum, which makes up the largest portion; the cerebellum; & brainstem. The cerebrum is divided
into two hemispheres sometimes called the left & right brains. They are connected by a structure called the corpus callosum.
FIG. 5-2 Central nervous system comprises the brain & spinal cord.
The surface of the cerebrum, called the cortex, is characterized by deep folds & shallow grooves, which increase its surface area
& maximize function. The cortex is full of neurons as well as specialized support cells, called glia, that carry nutrients to the
neurons. It is divided into four areas known as the frontal, temporal, parietal, & occipital lobes. Each of these areas is responsible
for specific functions, such as sensory perception, movement, emotions, memory, & behavior. The cerebellum is sometimes called
the “little brain.” It is located inferior & posterior to the rest of the brain. It is about the size of your fist & is shaped like a walnut. It
also has folds & grooves, similar to the cerebrum. It’s responsible for posture, balance, & coordination.
The brainstem sits anterior to the cerebellum & includes the medulla oblongata, pons, & midbrain. It’s an essential pathway that
conducts impulses bet. the brain & spinal cord & controls autonomic functions, such as breathing, swallowing, heart rate, blood
pressure, consciousness, & the sleep-wake cycle. The brain is enclosed & protected by the hard bones of the skull, known as
the cranium (Box 5-1).
The spinal cord is neural tissue that extends from the medulla oblongata down to the second lumbar vertebra. The vertebral
column surrounds & protects the spinal cord (Fig. 5-3). It’s divided into sections that correspond to the vertebrae & paired spinal
nerves. The spinal cord contains the pathways for sensory impulses, which provide information from the rest of the body to the
brain, & pathways for motor impulses, which send messages from the brain to the rest of the body.
Flashpoint
Many people believe that they are either “left-brained” (logical & analytical) or “right-brained” (intuitive & creative). While 2 hemispheres
have somewhat different functions, dominance is related to the task we are trying to accomplish, not to the type of person we are.
Box 5-1 Traumatic Brain Injury Facts & Prevention
Traumatic brain injuries (TBIs) are most commonly caused by falls, by being hit by an object/by MVAs. Survivors can have
impairments that may last for a few days/for the rest of their lives. There are many ways a TBI can affect an individual, depending on
where the brain was injured. For example, an injury to the front of the brain, or frontal lobe, may cause problems with decision making,
problem-solving, behavior, & self-control. An injury to the cerebellum, the back of the brain, may cause problems with balance &
coordination. Other areas of the brain control emotions, memory, speech, language comprehension, object recognition, & much more.
Many TBI survivors require long-term rehabilitation. Their injuries may be life-changing events that also affect their families, their job,
& their ability to interact in the community.
Anybody who is participating in activities such as skiing, snowboarding, or skateboarding & when riding on open, unrestrained
vehicles such as a bicycle, motorcycle, or snowmobile should wear a helmet.
MVAs are the leading cause of TBI-related death for children & young adults ages 5-24. When riding in cars, child safety seats should
be used, seat belts should be worn, & drivers should not operate the vehicle under the influence of alcohol or drugs. Even some
prescription medications can affect a person’s ability to drive safely.
In adults ages 65 & older, 81% of TBIs are caused by falls, & falls are the leading cause of TBI-related death in this age group. More
than half of these falls occur in the home. It’s a myth that falling is a normal part of aging! Communities throughout the U/S. are offering
comprehensive falls prevention programs, such as Stepping On, that teach older adults how to recognize & remove hazards in their
homes & SYSTEM
NERVOUS how to decrease the risk of falls through regularNERVOUS
vision checks, medication reviews, use of assistive devices,
SYSTEM.pdf & regularSYSTEM.pdf
NERVOUS exercise.
, NERVOUS SYSTEM.pdf NERVOUS SYSTEM NERVOUS SYSTEM.pdf
For more information about falls prevention or programs such as STEADI, visit the Centers for CDC website at www.cdc.gov or the
National Council on Aging (NCOA) website at www.ncoa.org.
The brain is protected inside the hard shell of the cranium, & the spinal cord is inside the vertebral column. Protecting both the
brain & the spinal cord are three membranes called the meninges. The meninges also provide a supportive structure for many
small blood vessels on the brain’s surface.
Cerebrospinal fluid continuously flows around the brain & spinal cord. This colorless fluid provides nutrients & helps remove
waste products. The fluid fills the subarachnoid space to form a cushion against injury from impact & sudden movement.
Learning Tip
Use Fig. 5-2 to create a three-dimensional model of the brain out of clay. Include the key parts described in this Ch. & make each out of a
different color. Name them & describe their function aloud as you make them. It’s okay if you aren’t a great sculptor—the point is to learn &
remember! Flashpoint
Dermatome has two meanings. As you learned in Ch. 4, a dermatome is also a surgical instrument that produces thin slices of skin.
FIG. 5-3 (A) The spinal cord & its spinal nerves are divided into sections that correspond to the vertebrae
regions.
The Peripheral Nervous System
PNS is located outside of, or peripheral to, the CNS & includes the nerves in the arms & legs. The PNS includes 31 pairs of spinal
nerves, 12 pairs of cranial nerves, & the nerves in the arms & legs. Almost all nerves are part sensory & part motor. Some cranial
nerves are all sensory or all motor. Sensory nerves gather information from the skin, the muscles, visceral organs, & the joints. The
information includes sensations such as temperature, touch, pressure, movement sense, position sense, & pain. These sensations
also allow us to distinguish Bet. sharp & dull & to recognize different weights, shapes, & textures of objects. This sensory
information is sent to the brain, & the brain responds by sending messages back out to the body via the motor nerves, which control
body movement. The message may be a conscious one that prompts you to action, such as putting on a coat if you are cold, or it
may be unconscious, causing you to reflexively lift your foot if you step on something sharp.
A key function of the 31 pairs of spinal nerves is innervation of the skin & muscles of the limbs. Areas of the skin associated
with specific spinal nerve roots are called dermatomes. Groups of muscles associated with specific spinal nerve roots are
called myotomes.
In injuries such as compression of a spinal nerve root, pain is felt along the associated dermatome rather than at the actual site of
injury. This referred pain & other symptoms, such as numbness or tingling, are felt in your arms or legs rather than in your neck or
back. Injury to spinal nerve roots may also cause muscle weakness in a group of muscles away from the site of injury. An injury to
a spinal nerve root in the neck may cause weakness of wrist muscles, & an injury to a spinal nerve root in the lower back may cause
weakness of ankle muscles.
Learning Tip
Using sticky notes, label dermatomes on a study partner. Name them aloud as you do so. Then change roles & let your partner do same with
you.
An important part of the PNS is the ANS, which controls involuntary functions. It consists of motor nerves to smooth muscle,
cardiac muscle, & glands such as sweat glands & salivary glands. It’s further divided into the sympathetic & parasympathetic
nervous systems (Fig. 5-4).
The sympathetic nervous system is responsible for the survival response known as the fight-or-flight response. This response
prepares a person for action, whether it is to fight in self-defense or to run from danger. Physical changes within the body caused by
this response include increased HR & force, increased BP & glucose levels, bronchodilation, & decreased intestinal peristalsis.
These changes provide the body with increased energy & oxygen while slowing some functions (such as digestion) that are less
NERVOUS SYSTEM NERVOUS SYSTEM.pdf NERVOUS SYSTEM.pdf
important at the time. The parasympathetic nervous system
NERVOUS SYSTEM 5
Chapter Outline
Structure & Function
The Neuron
The Central Nervous System
The Peripheral Nervous System
Combining Forms
Abbreviations
Pathologies
Procedures & Pharmacology
Common Diagnostic Tests & Procedures
Pharmacology
Case Study: Shingles
Chapter Practice Exercises
PREFIX & SUFFIX REVIEW
Study these Ch. 2 prefixes & suffixes; they are used often in medical terms for the nervous system. Be sure to read the Learning Tips throughout the
Ch. to find study suggestions that match your learning preferences!
Prefixes Suffixes
a- without, not, absence of -al, -ic, -tic pertaining to -metry measurement
dys- abnormal, bad, painful, difficult -algia, dynia pain -ology study of
hyper- excessive, above -cele hernia -oma tumor
iso- same, equal -ectomy excision, surgical removal -osis abnormal condition
macro- large -genesis, -genic creating, producing -pathy disease
micro- small -ia condition -plasia formation, growth
para- beside, near -itis inflammation -rrhaphy suture, suturing
poly- much -kinesis movement -tomy cutting into, incision
-lysis destruction -tripsy crushing
-malacia softening -trophy nourishment, growth
-megaly enlargement -uria urine
Flashpoint
Your brain is something like a very complex computer with infinite data-storage capabilities.
Structure & Function
The nervous system receives information from the external environment as well as from the internal body to communicate &
coordinate your everyday functions. It plays a key role in maintaining homeostasis (home/o = same, -stasis = stopping), the state
of dynamic equilibrium in the internal environment of the body. More complex than the most advanced computer, the nervous
system is capable of storing vast amounts of data as well as receiving & sending thousands of messages throughout the body
instantly & simultaneously.
While the nervous system functions as a total system, you may find it more easily understood if we divide it into its two major
parts: CNS & the PNS. However, we first begin by looking at the most essential element: the neuron.
The Neuron
A nerve cell, known as a neuron, is illustrated in Fig. 5-1. Neurons vary in size & shape, but they all have the following key parts:
cell body, axon, & dendrites. The cell body houses the nucleus & other microscopic structures that keep the cell energized &
functioning. The dendrites, which resemble the branches of a tree, are responsible for receiving information from the internal &
external environment & bringing this information to the cell body. The axon sends electrical signals, or impulses, to other cells.
The axon may be short or quite long & is often coated in a protective layer called the myelin sheath. Myelin is a fatty substance that
also helps to increase the speed of nerve impulses from one axon to another. In diseases such as multiple sclerosis, the myelin
sheath is damaged, which slows down the impulses or prevents them from reaching their destination.
FIG. 5-1 Neurons contain a cell body, axon, &
dendrites. The gaps Bet. the axons &
dendrites of two neurons are synapses.
A nerve cell in the human body functions somewhat like an electrical cord in your home. In an electrical cord, the wires
are protected by a rubber coating of insulation; so too, your nerves are protected by the myelin sheath. The electrical cord sends
electricity from the energy source to the refrigerator,NERVOUS
NERVOUS SYSTEM
television, or other device so that it can operate. Your
SYSTEM.pdf
nerve cells send
NERVOUS SYSTEM.pdf
,NERVOUS SYSTEM.pdf NERVOUS SYSTEM NERVOUS SYSTEM.pdf
electrical impulses down t axon to muscles, organs, or other tissues in the periphery so that they can function. When the insulating
layer of an electrical extension cord becomes frayed or otherwise damaged, the cord may “short out”; as a result, signal
transmission may be temporarily or permanently lost, & the device may no longer work. Similarly, if the myelin sheath on the axon
degenerates or is damaged, the electrical impulse may be temporarily or permanently lost. As a result, the organ or muscle that it
innervates may not function properly. This explains some of the symptoms caused by degenerative neuromuscular diseases such as
multiple sclerosis.
Learning Tip
Use the illustrations by tracing them with your fingertip, naming the various parts aloud, & describing their functions as you do so. This is
useful for visual, auditory, verbal, & kinesthetic learners.
The Central Nervous System
CNS comprises the brain & spinal cord (Fig. 5-2). CNS is where data storage & information processing occurs. The brain comprises
three major divisions: the cerebrum, which makes up the largest portion; the cerebellum; & brainstem. The cerebrum is divided
into two hemispheres sometimes called the left & right brains. They are connected by a structure called the corpus callosum.
FIG. 5-2 Central nervous system comprises the brain & spinal cord.
The surface of the cerebrum, called the cortex, is characterized by deep folds & shallow grooves, which increase its surface area
& maximize function. The cortex is full of neurons as well as specialized support cells, called glia, that carry nutrients to the
neurons. It is divided into four areas known as the frontal, temporal, parietal, & occipital lobes. Each of these areas is responsible
for specific functions, such as sensory perception, movement, emotions, memory, & behavior. The cerebellum is sometimes called
the “little brain.” It is located inferior & posterior to the rest of the brain. It is about the size of your fist & is shaped like a walnut. It
also has folds & grooves, similar to the cerebrum. It’s responsible for posture, balance, & coordination.
The brainstem sits anterior to the cerebellum & includes the medulla oblongata, pons, & midbrain. It’s an essential pathway that
conducts impulses bet. the brain & spinal cord & controls autonomic functions, such as breathing, swallowing, heart rate, blood
pressure, consciousness, & the sleep-wake cycle. The brain is enclosed & protected by the hard bones of the skull, known as
the cranium (Box 5-1).
The spinal cord is neural tissue that extends from the medulla oblongata down to the second lumbar vertebra. The vertebral
column surrounds & protects the spinal cord (Fig. 5-3). It’s divided into sections that correspond to the vertebrae & paired spinal
nerves. The spinal cord contains the pathways for sensory impulses, which provide information from the rest of the body to the
brain, & pathways for motor impulses, which send messages from the brain to the rest of the body.
Flashpoint
Many people believe that they are either “left-brained” (logical & analytical) or “right-brained” (intuitive & creative). While 2 hemispheres
have somewhat different functions, dominance is related to the task we are trying to accomplish, not to the type of person we are.
Box 5-1 Traumatic Brain Injury Facts & Prevention
Traumatic brain injuries (TBIs) are most commonly caused by falls, by being hit by an object/by MVAs. Survivors can have
impairments that may last for a few days/for the rest of their lives. There are many ways a TBI can affect an individual, depending on
where the brain was injured. For example, an injury to the front of the brain, or frontal lobe, may cause problems with decision making,
problem-solving, behavior, & self-control. An injury to the cerebellum, the back of the brain, may cause problems with balance &
coordination. Other areas of the brain control emotions, memory, speech, language comprehension, object recognition, & much more.
Many TBI survivors require long-term rehabilitation. Their injuries may be life-changing events that also affect their families, their job,
& their ability to interact in the community.
Anybody who is participating in activities such as skiing, snowboarding, or skateboarding & when riding on open, unrestrained
vehicles such as a bicycle, motorcycle, or snowmobile should wear a helmet.
MVAs are the leading cause of TBI-related death for children & young adults ages 5-24. When riding in cars, child safety seats should
be used, seat belts should be worn, & drivers should not operate the vehicle under the influence of alcohol or drugs. Even some
prescription medications can affect a person’s ability to drive safely.
In adults ages 65 & older, 81% of TBIs are caused by falls, & falls are the leading cause of TBI-related death in this age group. More
than half of these falls occur in the home. It’s a myth that falling is a normal part of aging! Communities throughout the U/S. are offering
comprehensive falls prevention programs, such as Stepping On, that teach older adults how to recognize & remove hazards in their
homes & SYSTEM
NERVOUS how to decrease the risk of falls through regularNERVOUS
vision checks, medication reviews, use of assistive devices,
SYSTEM.pdf & regularSYSTEM.pdf
NERVOUS exercise.
, NERVOUS SYSTEM.pdf NERVOUS SYSTEM NERVOUS SYSTEM.pdf
For more information about falls prevention or programs such as STEADI, visit the Centers for CDC website at www.cdc.gov or the
National Council on Aging (NCOA) website at www.ncoa.org.
The brain is protected inside the hard shell of the cranium, & the spinal cord is inside the vertebral column. Protecting both the
brain & the spinal cord are three membranes called the meninges. The meninges also provide a supportive structure for many
small blood vessels on the brain’s surface.
Cerebrospinal fluid continuously flows around the brain & spinal cord. This colorless fluid provides nutrients & helps remove
waste products. The fluid fills the subarachnoid space to form a cushion against injury from impact & sudden movement.
Learning Tip
Use Fig. 5-2 to create a three-dimensional model of the brain out of clay. Include the key parts described in this Ch. & make each out of a
different color. Name them & describe their function aloud as you make them. It’s okay if you aren’t a great sculptor—the point is to learn &
remember! Flashpoint
Dermatome has two meanings. As you learned in Ch. 4, a dermatome is also a surgical instrument that produces thin slices of skin.
FIG. 5-3 (A) The spinal cord & its spinal nerves are divided into sections that correspond to the vertebrae
regions.
The Peripheral Nervous System
PNS is located outside of, or peripheral to, the CNS & includes the nerves in the arms & legs. The PNS includes 31 pairs of spinal
nerves, 12 pairs of cranial nerves, & the nerves in the arms & legs. Almost all nerves are part sensory & part motor. Some cranial
nerves are all sensory or all motor. Sensory nerves gather information from the skin, the muscles, visceral organs, & the joints. The
information includes sensations such as temperature, touch, pressure, movement sense, position sense, & pain. These sensations
also allow us to distinguish Bet. sharp & dull & to recognize different weights, shapes, & textures of objects. This sensory
information is sent to the brain, & the brain responds by sending messages back out to the body via the motor nerves, which control
body movement. The message may be a conscious one that prompts you to action, such as putting on a coat if you are cold, or it
may be unconscious, causing you to reflexively lift your foot if you step on something sharp.
A key function of the 31 pairs of spinal nerves is innervation of the skin & muscles of the limbs. Areas of the skin associated
with specific spinal nerve roots are called dermatomes. Groups of muscles associated with specific spinal nerve roots are
called myotomes.
In injuries such as compression of a spinal nerve root, pain is felt along the associated dermatome rather than at the actual site of
injury. This referred pain & other symptoms, such as numbness or tingling, are felt in your arms or legs rather than in your neck or
back. Injury to spinal nerve roots may also cause muscle weakness in a group of muscles away from the site of injury. An injury to
a spinal nerve root in the neck may cause weakness of wrist muscles, & an injury to a spinal nerve root in the lower back may cause
weakness of ankle muscles.
Learning Tip
Using sticky notes, label dermatomes on a study partner. Name them aloud as you do so. Then change roles & let your partner do same with
you.
An important part of the PNS is the ANS, which controls involuntary functions. It consists of motor nerves to smooth muscle,
cardiac muscle, & glands such as sweat glands & salivary glands. It’s further divided into the sympathetic & parasympathetic
nervous systems (Fig. 5-4).
The sympathetic nervous system is responsible for the survival response known as the fight-or-flight response. This response
prepares a person for action, whether it is to fight in self-defense or to run from danger. Physical changes within the body caused by
this response include increased HR & force, increased BP & glucose levels, bronchodilation, & decreased intestinal peristalsis.
These changes provide the body with increased energy & oxygen while slowing some functions (such as digestion) that are less
NERVOUS SYSTEM NERVOUS SYSTEM.pdf NERVOUS SYSTEM.pdf
important at the time. The parasympathetic nervous system
