Transcript THERE IS A COMPUTER-LIKE SYSTEM IN OUR BODY

THE NERVOUS SYSTEM
THE BRAIN, SPINAL
CORD AND NERVES
ARE PART OF THE
NERVOUS SYSTEM
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NERVOUS SYSTEM
NEUROLOGICAL
NEURO
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Natural Aging Changes in the
Nervous System
 Brain cells degenerate
 Nervous impulses
 Responses/reflexes
 Changes in sleep patterns
 Memory changes
 Changes in vision/hearing
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Learning the Nervous System:
5 Levels
Handout
1. Cell level (Neuron)
2. Central Nervous System (CNS)
3. Peripheral Nervous System (PNS)
4. Autonomic Nervous System (ANS
5. Somatomotor Nervous System
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DIVISIONS OF THE NERVOUS
SYSTEM
FOUR MAIN DIVISIONS OF
NERVOUS SYSTEM
 1. CENTRAL NERVOUS
SYSTEM; CONSISTS OF
THE BRAIN AND SPINAL
CORD
 2. PERIPHERAL NERVOUS
SYSTEM; MADE UP OF ALL
NERVES IN PERIPHERY
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DIVISIONS OF NERVOUS
SYSTEM
3. AUTONOMIC
NERVOUS SYSTEMHaving to do with
involuntary smooth
muscle controL
4. SOMATOMOTOR
NERVOUS SYSTEMVoluntary control, innervate
skeletal muscle tissue
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NEURON
 IT IS ALSO CALLED THE NERVE CELL
 PARTS OF A NEURON: A CELL BODY, A
NUCLEUS INSIDE THE CELL BODY, AND NERVE
FIBERS
 WE HAVE OVER 100 BILLION NEURONS
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NERVE FIBERS
 DENDRITES CARRY IMPULSES TOWARD THE CELL
BODY AS THEY RECEIVE MESSAGES FROM SENSORY
ORGANS
 AXONS ARE SINGLE NERVE FIBERS THAT CARRY
IMPULSES AWAY FROM THE CELL BODY OFTEN TO
MUSCLES
 MANY AXONS ARE COVERED WITH A FATTY COVERING
CALLED A MYELIN SHEATH
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 THE MYELIN SHEATH INCREASES THE
RATE OF TRANSMISSION OF AN IMPULSE
AND INSULATES AND MAINTAINS THE
AXON IN THE NERVE FIBERS OF THE
PERIPHERY
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NERVE FIBERS
 DENDRITES TEND TO BE SHORT AND
HAVE MANY BRANCHES WHILE AXONS
ARE LONGER AND BRANCH LESS.
THE SPACE BETWEEN THE AXON OF 1
CELL AND THE DENDRITES OF ANOTHER IS
CALLED A SYNAPSE.
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NERVE IMPULSES
(Handout)
Neurons are excitable. When stimulated, they
undergo chemical changes that produce tiny
traveling waves of electricity called impulses.
These pass to other neurons, initiating similar
responses from them. These impulses are all
over the body, about 100 millivolts in strength
and lasting just 1 millisecond! These impulses
“jump” from 1 neuron to another at the synapse.
When the electrical impulse arrives at the
synapse, it triggers the release of chemicals
called neurotransmitters.
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NERVE IMPULSES
(Handout)
NEUROTRANSMITTERS CROSS THE
INCREDIBLY THIN SPACE BETWEEN THE
SENDING AND RECEIVING NEURON
(SYNAPSE). THEY EITHER TRIGGER A NEW
IMPULSE OR ACTIVELY INHIBIT IT FROM
FIRING. IF THE CHEMICALS ARE NOT
PRODUCED IN THE RIGHT AMOUNTS, THE
MESSAGE PATHWAY BECOMES
“CONFUSED” OR BLOCKED.
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Video
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NERVES
 COMBINATION OF
MANY NERVE
FIBERS
 LOCATED OUTSIDE
THE BRAIN AND
SPINAL CORD
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 AFFERENT OR SENSORY NERVES CARRY
MESSAGES FROM ALL PARTS OF THE
BODY TO THE BRAIN AND SPINAL CORD
 EFFERENT OR MOTOR NERVES CARRY
MESSAGES FROM THE BRAIN AND
SPINAL CORD TO MUSCLES AND GLANDS
“SAME” =
Sensory Afferent, Motor Efferent
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CENTRAL NERVOUS
SYSTEM:
BRAIN AND SPINAL CORD
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BRAIN
 SURROUNDED BY BONE
 PROTECTED BY MEMBRANE CALLED
MENINGES
 CUSHIONED BY CEREBRAL
SPINAL FLUID (CSF)
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CEREBRUM
 LARGEST SECTION OF
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THE BRAIN
FORMED IN FOLDS
2 HEMISPHERES (R/L)?
4 LOBES
RESPONSIBLE FOR
REASONING,
THOUGHT, MEMORY,
SPEAKING,
MOVEMENT,
EMOTIONS,
INTELLIGENCE
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CEREBRUM
 The outer portion of the cerebrum is called
the CEREBRAL CORTEX. This area is
mostly composed of cell bodies and appears
gray.
 The inner portion is composed of axons and
dendrites and appears white.
 Each of the 4 lobes has certain activities they
are responsible for.
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The Frontal Lobe
 The
Frontal Lobe is
responsible for:
 motor functions
 language
 Impulse control
 Social behavior
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The Parietal Lobe
 The
Parietal Lobe
is responsible for:
 Sensory functions
 Spatial awareness
 Pain
 Math
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The Temporal Lobe
Temporal
Lobe is responsible
 The
for:
 Personality changes
 Emotions
 Memory
 Hearing
 Alzheimer’s Disease
affects this lobe
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The Occipital Lobe
 The Occipital
Lobe is
responsible for:
 Visual perception
 Interprets what you
see
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Next section of the
brain……..CEREBELLUM
 SECTION BELOW THE
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BACK OF THE
CEREBRUM
RESPONSIBLE FOR:
COORDINATION OF
MUSCLES
BALANCE AND
POSTURE
EQUILIBRIUM
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Next section of the
brain…….DIENCEPHALON
 Between cerebral hemispheres/deep deep
inside brain
 Includes:
1. Thalamus- processing center, initiates
movement, sorts information
2. Hypothalamus- controls pituitary gland,
regulates body temperature, water balance in
body
3. Epithalamus- Pineal gland/Secretes
melatonin for sleep/wake cycle
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Next section of the
brain……….BRAINSTEM
INVOLUNTARY MOVEMENTS OF VITAL
CENTERS (HEART RATE, BLOOD PRESSURE,
RESPIRATORY RATE_
1. Midbrain- visual/auditory reflexes
2. Pons- respiratory center
3. Medulla Oblongata- connects to the
spinal cord, control center for respiratory
rate, blood vessels,swallowing, heart rate
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SPINAL CORD
 CONTINUES DOWN
FROM THE MEDULLA
OBLONGATA
 ENDS AT THE FIRST
OR SECOND LUMBAR
VERTEBRAE
(17”LONG AND
¾”THICK
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SPINAL CORD

Protected by vertebral bone structure,
CSF, and meninges:
1. Dura Mater- outer
2. Arachnoid Mater- middle, mostly
CSF
3. Pia Mater- inner
membrane/vascular
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The Spinal Cord
 CARRIES SENSORY
(AFFERENT) MESSAGES
UP TO THE BRAIN
 CARRIES MOTOR
(EFFERENT) MESSAGES
FROM THE BRAIN TO THE
NERVES, WHICH GO TO
MUSCLES AND GLANDS
 Nerves innervate or go into
organs and muscles from
spinal cord
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PERIPHERAL NERVOUS
SYSTEM
 CONNECTS CNS
TO “PERIPHERY”
 CONSISTS OF
CRANIAL NERVES
AND SPINAL
NERVES
 AFFERENT AND
EFFERENT
NERVES
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CRANIAL NERVES
 12 cranial nerves that arise from the brain
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SPINAL NERVES
 THIRTY-ONE PAIRS
AND THEIR BRANCHES
 CARRY MESSAGES TO
AND FROM THE
SPINAL CORD
 BOTH
SENSORY(AFFERENT)
AND MOTOR
NERVES(EFFERENT),
OR MIXED NERVES
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DISORDERS OF PNS
1. Neuralgia- nerve pain
2. Bell’s Palsy- Cranial Nerve VII is damaged causing
facial paralysis
3. Sciatica- pain from Sciatic Nerve in buttocks
4. Polio- CNS infection with PNS results (atrophy from
damage to motor neurons)
5. Myasthenia Gravis- muscular weakness caused by
degeneration of nerve/muscle junction. Lack of
neurotransmitter acetylcholine
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AUTONOMIC NERVOUS
SYSTEM
 The nerves
INNERVATE the
organs. Under
Involuntary control.
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AUTONOMIC NERVOUS
SYSTEM
 HELPS MAINTAIN A BALANCE IN THE
INVOLUNTARY FUNCTIONS OF THE
BODY, BUT ALLOWS THE BODY TO
REACT IN TIMES OF EMERGENCY
 TWO DIVISIONS: SYMPATHETIC AND
PARASYMPATHETIC
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SYMPATHETIC NERVOUS
SYSTEM
 ACTS IN TIMES OF
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EMERGENCY SUCH
AS FIGHT OR FLIGHT
PREPARES THE
BODY TO ACT
INCREASES HEART
RATE AND
RESPIRATION
RAISES BLOOD
PRESSURE
SLOWS ACTIVITY IN
THE DIGESTIVE
TRACT
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PARASYMPATHETIC
NERVOUS SYSTEM
 COUNTERACTS THE
ACTIONS OF THE
SYMPATHETIC AFTER
THE EMERGENCY
 SLOWS THE HEART
RATE AND
RESPIRATION
 LOWERS THE BLOOD
PRESSURE
 INCREASES THE
ACTIVITY IN THE
DIGESTIVE TRACT
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SOMATOMOTOR NERVOUS
SYSTEM
Mostly under VOLUNTARY control; these nerves
innervate skeletal muscle tissue
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