Download The Nervous System - Primary Home Care

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Lesson 14
The Nervous System
In this chapter... you will learn about:
• The nervous system.
• Some common problems of the nervous system.
Definitions
Aphasia:
Loss of language or verbal communication.
Chronic Brain
Large areas of the brain stop functioning, causing memory
Syndrome Alzheimer's
loss, fear and poor judgment.
Type Dementia):
Dementia:
Mental deterioration, loss of ability to think clearly.
Equilibrium:
Balance.
Hemiplegia:
Paralysis on one side of the body.
Hemisphere:
Half of a round mass of tissue.
Linear:
Following in order along a line.
Neurons:
Specialized cells of the nervous system.
Definitions continued……..
Definitions continued...
Parkinson's Disease: Disorder of the nervous system resulting in body
stiffness and shakiness.
Peripheral:
Away from the center of something.
Reflexes:
Automatic responses to stimulation.
Spatial:
Oriented in space.
Stroke (Cerebral
Vascular Accident
or CVA):
Sudden stoppage of the blood supply to an area of the
brain.
Vertebrae:
Bones of the spine.
The Nervous System
The nervous system is the control and communication center for
the body. It causes all the other body systems to function. It
enables you to see, hear, feel, talk, smell, taste, move, think, and
remember.
The nervous system is made of:
1. The brain, which has three main parts.
2. The spinal cord, which extends from the brain dawn your
spinal column.
3. Peripheral nerves, that extend outward from the brain
and spinal column and carry messages to and from all parts
of the body.
These three parts work together to control and coordinate all body
activities.
The Nervous System
Brain
The brain fits inside our skull and weighs about three pounds in an
adult. The soft, wavy material we associate with the word brain is
called the cerebrum or cerebral cortex. This is the largest part of the
brain, and it controls all the functions associated with thinking and
voluntary activity. Deciding to walk across the room is a voluntary
activity.
Sitting beneath the cerebrum, or
top part of the brain, in the back
of the skull is the cerebellum. The
cerebellum is involved in
coordinating voluntary movements
and helps maintain equilibrium.
The Nervous System
Brain
Beneath the cerebrum is the midbrain. This
section connects the cerebrum with the
spinal cord and carries messages to and from
the cerebral cortex. It also controls all the
involuntary functions of the body, such as
breathing, peristalsis in your intestine, and
heartbeat. You don't have to think about
these activities; they happen automatically.
The Nervous System
Brain
Scientists have learned that the cerebrum contains specific
areas which control specific functions. The main division is
into right and left hemispheres. The right hemisphere
controls the left side of the body and is usually the site of
the centers for spatial and creative functions. The left
hemisphere controls the right side of the body and, for most
people, it is the site of speech and linear thought. These
hemispheres look basically the same. Each is divided into
lobes which are the sites of specific functions:
The Nervous System
Brain
1. Frontal lobes - area of speech, reason, thought and. the motor
area directing actions.
2. Parietal. lobes - sensations of touch, pain, pressure, and
temperature change.
3. Occipital lobes - sight.
4: Temporal lobes - hearing and. the .sense of smell.
The Nervous System
Spinal Cord
The spinal cord is a long bundle of nerves, like a cable, that carries
messages to and from . the brain. It is connected to the medulla
and runs down the spine inside the vertebrae to the hip area. In
addition to relaying messages, the spinal cord is the center for
reflexes. These are automatic responses to stimulation. You don't
have to think about taking your hand off a hot stove; when your
hand jerks back, it is a reflex action.
The Nervous System
Peripheral Nerves
The information relayed by the spinal cord comes from and is sent
to nerves running to all parts of the body. If you stub your toe, this
information travels from your toe, up your leg to the spinal cord
which tells your brain that your toe hurts.
The cells of the nervous system are called neurons. Neurons are
different from other cells because it is believed that they do not
reproduce themselves. Even if neurons are not replaced when they
die, this should not seriously affect functions since we each have
billions of neurons in our nervous system.
The Nervous System
Phrenic Nerve
Sciatic
Cerebrum
Cerbellum
Spinal Cord
Radial
Femoral
The Nervous System
Age-Related Changes
The loss of neurons does not mean that there is a loss of
intelligence. Intellectual abilities can increase as people age if they
continue to use their brains. There is a general slowing of nervous
system function as a person ages, just as all other physical systems
tend to function more slowly. When this happens gradually, as in
normal aging, the brain can adapt. When damage occurs more
quickly, such as in some diseases, the brain may not be able to adapt
and greater changes in function and thought processes may occur.
The Nervous System
Diseases of the Nervous System
Many diseases affect the central nervous system and
can disrupt the message system between the brain and
the body.
Some of these diseases are:
The Nervous System
Diseases of the Nervous System
Stroke (Cerebral Vascular Accident or CVA). This is a disease of
the circulatory system which affects brain function. It is
caused by a blood clot or bleeding in the brain which destroys
brain tissue. A stroke often affects the part of the brain
controlling movement, and the client may be paralyzed on one
side. This is called hemiplegia. Strokes can also affect the
speech centers and the client may have aphasia. The aphasia
may affect the ability to produce speech, to speak intelligently,
or to understand speech.
The Nervous System
Diseases of the Nervous System
Parkinson's disease. This is a progressive disease of the
brain. It causes the client to have tremors, or
shaking; stiff, rigid muscles; a shuffling gait; and
general weakness. Intelligence, however, is not
affected. Medication often helps ease some of these
problems.
The Nervous System
Diseases of the Nervous System
Chronic Brain Syndrome (also called Alzheimer's-Type Dementia).
In this condition large areas of neurons cease to function and
the client cannot remember what just happened, has poor
judgment, and has great fear and anxiety. Clients may forget
who family and friends are, how to do simple tasks, and how to
care for themselves. These clients need a safe, caring
environment. Behavior will change due to diseases of the nervous
system. It is important to remember that the disease causes
the change. The behavior is not intentional. You will learn more
about dealing with Alzheimer's and other dementias in a later
chapter.
 Complete the test and turn in for credit
Answer ALL TEST questions.
Check your answers
 Be sure to sign and date the test sheet.
This completes the lesson
for this month.
Information for this lesson was taken from MEDCOM TRAINEX publications