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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CNS PROTECTIVE STRUCTURES• 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.


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CNS PROTECTIVE STRUCTURES• 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.


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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.


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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.


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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.


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COMPONENTS OF THE CNS• The Neuron

– The Neuron is comprised of the Soma (cell body) and:• Dendrites

• Nucleus

• Nucleolus

• Synapse

• Terminal Button

• Axon

• Myelin Sheath

• Nodes of Ranvier


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COMPONENTS OF THE CNS• 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.


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– 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


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– 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.


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– Reticular Activity System• Responsible for consciousness.

• Keeps us alert and out of trouble.

• Involved in sleep-wake cycle


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COMPONENTS OF THE CNS• 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.


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COMPONENTS OF THE CNS• 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


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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


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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 toassess for stroke among otherdisorders.


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Central nervoussystem lesson1