Central nervoussystem lesson1

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Emergency Services, LLC / Copyright 2013
Hands-On:
Central Nervous System Training, Lesson 1
CNS PROTECTIVE STRUCTURES
• The scalp
– A strong flexible mass of skin and fascia able to withstand
and absorb tremendous amounts of kinetic energy.
Protects the brain from both trauma and the extremes of
weather.
• The Skull & Facial Bones
– A series of cranial and facial bones that protect the brain
– Skull bones: Frontal, Parietal, Temporal, and Occipital
– Facial bones: Nasal, Maxilla, Orbit, Mandible, and Zygoma

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• The Vertebral Column
– The column protects the spinal cord and allows for
mobility of the head and upper body. It is comprised of 32-
34 separate and irregular bones, divided into five specific
regions.
– These regions are the cervical (7 vertebrae), thoracic (12
vertebrae), lumbar (5 vertebrae), sacral (5 vertebrae) and
coccygeal spine (4 vertebrae).
– Structures include the Vertebral Facets, Spinal Nerves,
Spinal Cord, and Intervertebral Disc.
Hands-On:

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• Other Structures
– They are a group of three tissues between the skull and
the brain and between the inside of the spinal foramen and
the cord.
• Cerebrospinal fluid (CSF)
– The medium that surrounds the central nervous system
and acts to absorb shocks of minor deceleration. The area
below the arachnoid membrane, called the subarachnoid
space, contains the CSF. The brain constantly generates
CSF and it circulates throughout the brain and spinal cord
before being reabsorbed.
Hands-On:

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CONTENTS OF THE SKULL
• The scalp
– A strong flexible mass of skin and fascia able to withstand
and absorb tremendous amounts of kinetic energy.
Protects the brain from both trauma and the extremes of
weather.
• Dura Mater
– Latin for “Tough Mother,” a tough, thick, inelastic fibrous
outermost layer that is the first line of intracranial
protection.
– Meningial arteries are located between the bony skull and
the dura. This area is referred to as the epidural space,
although it is only a potential space.
Hands-On:

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CONTENTS OF THE SKULL
• Arachnoid
– Thin layer loosely covering the central nervous system.
– Space beneath the arachnoid is filled with cerebrospinal
fluid.
– Filaments cross the “subarachnoid space” connecting the
arachnoid to the inner most layer of the meninges, the pia
mater.
• Pia Mater
– Latin for “soft mother”, attaches to and covers the brain
cortex, it also attaches to the arachnoid layer in some
places.
– Contains many small capillaries that supply blood to the
central nervous system.
Hands-On:

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COMPONENTS OF THE CNS
• The Neuron
– This is the functional unit of the central nervous system.
CNS neurons differ in structure from peripheral neurons.
– The main difference between the two is the protective
protein sheath (called neurilemma) that is present in
peripheral neurons.
Hands-On:

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• The Neuron
– The Neuron is comprised of the Soma (cell body) and:
• Dendrites
• Nucleus
• Nucleolus
• Synapse
• Terminal Button
• Axon
• Myelin Sheath
• Nodes of Ranvier
Hands-On:

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• The Brain
– The brain is a mass of neurons which is the control center
of the body. It is divided into several different regions,
including all of the following:
• Cerebrum (Cerebral Cortex)
• Cerebellum
• Medulla Oblongata
• Pons
– Cerebellum
• Located in the posterior fossa of the intracranial space.
• Responsible for movement and coordination.
Hands-On:

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• The Brain
– Brain Stem
• Stem-like portion of the brain that controls vegetative
functions ( i.e. respiration, heart rate), and connects the brain
to the spinal cord.
• Divided into the Midbrain, Pons, Medulla Oblongata, and the
Reticular Activity System.
– Mid-Brain
• Involved in hearing and visual reflexes
Hands-On:

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• The Brain
– Medulla Oblongata
• Located between the Pons and spinal cord.
• Contains the centers that control heart rate, respirations, and
constriction of vessel walls.
– Pons
• Relays information from the Cerebrum to the Cerebellum.
• Houses the sleep center and the respiratory center, which
along with the Medulla controls breathing.
Hands-On:

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• The Brain
– Reticular Activity System
• Responsible for consciousness.
• Keeps us alert and out of trouble.
• Involved in sleep-wake cycle
Hands-On:

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• Lobes of the Brain
– Frontal lobe
• The frontal region is anterior and controls personality,
expressive language and consciousness.
– Parietal lobe
• The parietal region is superior and posterior; it controls goal-
directed voluntary movements and manipulation of objects. It
also interprets sensory information.
Hands-On:

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• 12 Cranial Nerves
– Names & Functions
• Olfactory - Sense of smell
• Optic - Vision
• Oculomotor - Eye movements
• Trochlear - Eye movements
• Trigeminal - Sensations of face, scalp and teeth, chewing
movements
• Abducens - Turning eyes outwards
• Facial - Sense of taste, facial expressions
Hands-On:

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– Names & Functions
• Acoustic - Hearing, sense of balance
• Glossopharyngeal - Sensations of the throat, taste-swallowing
movements, secretion of saliva
• Vagus - Sensations of the throat and larynx and of the thoracic
and abdominal organs, swallowing, voice production, slowing
of heartbeat, and acceleration of peristalsis (muscle
contractions)
• Spinal Accessory - Shoulder movements, turning of the head
• Hypoglossal - Tongue movements
Hands-On:

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– Cranial nerves do not cross.
• Therefore, a right cranial nerve
insult will result in right- sided deficit.
– We check the cranial nerves to
assess for stroke among other
disorders.
Hands-On:

Central nervoussystem lesson1

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