Download Nervous Power Point

The Nervous System
Introduction to Health science
Vocabulary- Combining Forms
• Cerebr/o
• Encephal/o
• Gli/o
• Mening/o, meningi/o
• Myel/o
•
•
•
•
Neur/o
Psych/o
Spin/o
Tox/o, toxic/o
cerebrum
brain
glue/ neurologic
tissue
meninges
spinal cord/ bone
marrow
nerve
mind
spine
toxic
Vocabulary- Prefixes and Suffixes
• para-
near, beside,
• -lysis
beyond
• -al
• -algia
• -cele
• -itis
• -logist
• -logy
pertaining to
pain
herniation,
swelling
inflammation
specialist
• -megaly
• -oma
• -osis
• -pathy
• -tome
study of
• -tomy
separation,
destruction,
loosening
enlargement
tumor
abnormal
condition
disease
instrument to
cut
incision, to cut
Vocabulary- abbreviations
• ANS
Autonomic Nervous System
• CNS
Central Nervous System
• CSF
Cerebral Spinal Fluid
• CVA
Cerebral Vascular Accident
(stroke)
• PNS
Peripheral Nervous System
Vocabulary
• Afferent
• Arbor vitea
• Efferent
going toward the brain/ the sensory
pathways
tree like structure inside the cerebellum
going away from the brain/ the motor
pathways
• Cauda equina
“horses tail” the lower end of
the spinal cord bundled together
• Corpus callosum bundle of nerves that connect
the right and left hemispheres of the
brain
• Hemisphere 2 halves of brain- right and left
hemisphere
Functions of the Nervous System
• Sensation (Sensory)
• Integration
• Movement (Motor)
Functions of the Nervous System
• Sensation
– The ability of the nerves to detect
stimuli, such as pressure, temperature
changes, taste, smell or light, and send
a message in the form of impulses to
the brain and spinal cord.
– Uses Sensory pathways, also known as
Afferent pathways
Functions of the Nervous System
• Integration
– The nervous system receives and
responds to internal and external
sensory stimuli.
– This is when it analyses and processes
information. It decides if the information
is important enough to act on.
– Can happen in the brain or spinal cord.
Functions of the Nervous System
• Movement
– The ability of the brain to send impulses
through motor nerves to muscles and
glands to cause movement or secretion
of hormones
– Uses Motor pathways, also known as
Efferent pathways.
Nerves
• Nerves (neurons) are the basic units
of structure and function for the
nervous system.
• Nerves are capable of sending
electrical messages called impulses.
• There are two main types of nerves:
• Sensory (afferent)
• Motor (efferent)
Types of Nerves
• Sensory nerves which detect changes
and carry impulses to the brain and spinal
cord from the sense organs.
• Motor nerves which detect changes and
carry impulses away from the brain and
spinal cord to muscles and organs.
Nerve Structure
• There are three basic parts of a
neuron:
– Dendrites
• Short, branchlike extensions which conduct
electrical signals toward the cell body.
– Cell Body
• Contains large nucleus and other cellular
organelles.
– Axon
• Extends from the cell body. Responsible for
carrying nerve impulses to other neurons,
muscles or glands.
Neuron
Dendrites
Cell body
Axon
Myelin
sheath
• The axon may be covered with myelin sheaths
that act as insulation to protect the nervous
impulse and speed the transmission
Grey and White Matter
• When a neuron is covered by a myelin sheath it
looks different than when it is not covered.
– Grey Matter has NO Myelin Sheath
– White Matter has a Myelin Sheath
– Notice that in the brain the grey matter is
superficial but in the spinal cord the grey
matter is deep to the white matter
Nervous System Divisions
• The largest division is between the
CNS (Central Nervous System) and
the PNS (Peripheral Nervous
System)
– The CNS contains the Brain and Spinal
Cord
– The PNS contains all the nerves as they
exit the spine and run throughout the
body
Nervous System Divisions
• The Peripheral Nervous System can
be broken down further into:
– The Autonomic Nervous System
(ANS) which has
• the Sympathetic
• the Parasympathetic
• This system does most of the involuntary
functions in the body
– The Somatic Nervous System
• This system controls the voluntary functions
in the body
Nervous System Divisions
The Brain
• The brain contains approximately 100
billion neurons. The brain weighs about 3
pounds. About 20% of blood leaving the
heart circulates through the brain.
• The brain is responsible for analyzing
information, processing information and
relaying messages to the rest of the body.
• It is the main control center of the body.
Parts of the Brain
• Cerebrum
– Frontal
– Parietal
– Temporal
– Occipital
• Cerebellum
• Diencephalon
– Thalamus
– Hypothalamus
• Brain Stem
– Medulla Oblongata
– Pons
– Midbrain
The Cerebrum
• The cerebrum is the largest part of the
brain. It has two distinct halves called
hemispheres. They are connected by
a band of tissue called the corpus
callosum. The cerebrum has many
folds and grooves (called sulci and
gyri) to increase the surface area and
the number of nerves found in the brain.
• The cerebrum is divided into four lobes.
• Notice the division
between the
hemispheres
• The sulci and gyri are
obvious, and increase
the surface area of the
cerebrum
Cerebral Lobes
• Frontal Lobe- controls skeletal muscle
movement, interprets the sense of smell, is
responsible for our personalities, and our ability to
learn, think, problem solve and concentrate.
• Parietal Lobe- interprets many of our senses
including taste, touch, temperature, and pain.
• Occipital Lobe- interprets the sense of sight.
• Temporal Lobe- interprets the senses of balance
and hearing. It also contains structures (such as the
hippocampus) which store memory.
Cerebral Lobes
Cerebellum
• The cerebellum is the second largest part of the
brain. In fact, cerebellum means the “little
cerebrum.” It is located inferior to the occipital
lobe.
• It functions to coordinate muscular movements
and helps the muscles move gracefully and
efficiently. It also helps with the body’s ability to
balance.
• The arbor vitae is the tree like structure seen
when the cerebellum is dissected.
The Diencephalon
• Main structures include the
– Hypothalamus
• Maintains homeostasis and controls the regulation of
hunger, thirst, body temperature, breathing, internal
organ activity, and sleep.
– Thalamus
• Vision, touch (including pain, temperature, pressure),
taste, hearing, and is critical for awareness.
• Relays sensory information between brain
regions and controls many autonomic
functions of the PNS.
• It also connects structures of the endocrine
system with the nervous system.
The Diencephalon
Brainstem
• The brain stem is located inferior
to the cerebellum and connects
the spinal cord to the brain.
• The brain stem is composed of
three structures
–Medulla Oblongata
–Pons
–Midbrain
The Medulla Oblongata
• Is continuous with the spinal cord.
• Controls autonomic functions such as
heart beat, blood pressure, breathing,
swallowing, hiccupping, vomiting, and
gagging.
• It also relays nerve impulses between
the brain and the spinal cord.
The Pons
• In Latin, the word pons literally
means bridge.
• It is the small bulge superior to the
Medulla
• It regulates the rate and depth of
breathing.
• Helps in the transferring of messages
between various parts of the brain
and the spinal cord.
The Midbrain
• Is the nerve pathway to the
hemispheres.
• Deals with vision, hearing, eye
movement, and body movement.
Midsagittal Cut of the Brain
Corpus
callosum
cerebrum
Sulci
Cerebellum
Gyri
Spinal
cord
Medulla
oblongata
Pons
Mid
brain
Diencephalon
The Spinal Cord
• Along with the brain, it is part of the
Central Nervous System.
• It is the major communication link
between the brain and the rest of the
body.
• It can process many reflexes –
unconscious, automatic responses to
stimuli.
• There are 31 pairs of spinal nerves which
branch from the spinal cord to control such
processes as breathing, arm movement,
and leg movement.
• The true spinal cord
ends in the upper
lumbar region (L1), after
that it turns into what is
called the cauda equina
or horses tail.
– Many small individual
nerves bundled together
Cerebrospinal Fluid
• CSF is a clear, watery fluid which bathes the brain
and the spinal cord to protect it by acting as a
shock absorber.
• CSF allows for the exchange of nutrients and
waste products between the blood and the
nervous tissue.
• CSF circulates between the two layers of the
meninges, through the center of the spinal cord,
and through large openings in the brain
(ventricles).
Meninges
• A set of three layers of connective tissue that
enclose the brain and spinal cord. They are
located under the skull and attach directly to the
brain.
• Meninges help to provide a small amount of
protection to the brain and spinal cord.
• Cerebrospinal fluid circulates between two layer of
the meninges.
• The three layers
– Dura mater
– Arachnoid
– Pia mater
“tough mother” outer layer
web like central layer
“delicate mother” inner layer
Diseases and Disorders of the Nervous System
•
• There are two types
Bacterial Meningitis
Viral Meningitis
Meningitis
– Meningitis is an
infection that causes
the inflammation of the
brain and spinal cord
coverings.
– Symptoms include
fever, chills, headache,
nausea, vomiting, and
stiff neck
– Treatment: antibiotics
for bacterial meningitis
and supportive
treatments for viral
meningitis
Epilepsy
• Epilepsy is a brain disorder involving
repeated seizures of any kind. Seizures are
episodes of disturbed brain function that
cause changes in attention or behavior.
• Symptoms:
• Loss of consciousness
• Staring spells
• Violent convulsions.
• Treatment:
• Varies depending on the
cause.
• May be controlled by
medications.
Concussion
• Post traumatic impairment of
neural function caused by a
direct blow to the head
resulting in bruising of the
brain.
– Symptoms may include headache, loss
of consciousness, ringing of the ears,
nausea, irritability, confusion,
disorientation, dizziness, amnesia or
difficulty concentrating.
– Treatment may include removal from
play, rest avoiding re-injury,
medications for pain, physical therapy
and relaxation.
Stroke
• Stroke, also known as a CVA or
cerebrovascular accident, occurs when there
is an interruption of the blood supply to any
part of the brain.
• Symptoms appear suddenly and
can include weakness or paralysis
of an extremity, numbness, vision
changes, slurred speech,
difficulty swallowing and loss of
memory
• It is important to get immediate
care to reduce permanent
complications. Physical therapy
and/or occupational therapy may
be needed.