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Nervous System

Nervous System

CNS-Central Nervous System

Control stimulates and coordinates all other

body systems

Command center

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Nervous System

PNS-Peripheral nervous system

Nerves outside the brain and spinal cord

Nervous System

ANS-Autonomic nervous system

responsible for control of the bodily functions

not consciously directed

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Nervous System

Fundamental unit of nervous tissue is the

neuron

Neuron is a nerve cell that includes the

dendrites and axons.

Nervous System

Dendrite- fiber branches that receive

impulses from other parts of the nervous

system and bring it to the cell.

Axons- transmit the impulses away from the

cell body. COLOR BK PG 13

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Nervous System

Myelin- fatty sheath surrounding the axon.

Speeds up impulse conduction.

Grey Matter is unmyelinated fiber, in the

cerebral cortex and central spinal cord

White matter is myelinated fiber within spinal

cord and fiber systems. COLOR BK PG 13/77

Nervous System

Synapse- transmission of impulses from one

neuron to another occurs at here.

COLOR BK PG 70

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Nervous System

Afferent neuron- sensory neuron takes the

message from the skin to the brain. Or

periphery to the CNS. COLOR BK PG 69

Nervous System

Efferent Neuron- motor neuron that takes the

message from the brain to the muscle. Or

CNS to the periphery. COLOR BK PG 69

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Nervous System-CNS

Central Nervous System is made up of the

Brain and spinal cord.

Brain is made up of the

cerebrum, brainstem

and

cerebellum.

Nervous System

Cerebrum is the largest and main portion of

the brain, it is responsible for the highest level

of function. It has four lobes.

COLOR BK PG 73

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Nervous System

The four lobes each have different functions.

Nervous System

Thalamus is inside the cerebrum, this is

where the nerve cells relay body sensations,

where pain is perceived. COLOR BK PG 75

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Nervous System

Cerebellum means “little brain.” The main

function is to control muscle coordination,

tone and posture. COLOR BK PG 76

Nervous System

Brainstem has three parts, the midbrain,

pons, and medulla. COLOR BK PG 76

Midbrain is center for visual reflexes

Medulla is the center for automatic control of

respiration and heart rate.

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Nervous System

Brain Protection

Skull- bones with fused joints for greater

strength of protection. COLOR BK PG 22

Nervous System

Brain Protection-three membranes-meninges

Dura mater-outer thickest layer that means in

latin COLOR BK PG 81

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Nervous System-Injuries

Nervous System

Brain Protection-three membranes-meninges

Arachnoid mater- middle layer

Subarachnoid space- where the shock

absorbing cerebrospinal fluid is located.

Pia mater- carries blood

vessels to the brain.

COLOR BK PG 81

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Nervous System

Spinal Cord is 17 inches long (approximate)

Has the same 3 protective layers as the brain

Outer dura mater

Arachnoid memebrane

Inner pia mater

Cerebrospinal fluid flows

between arachnoid layer

and pia mater

Spinal cord and spinal nerves

COLOR BK

PG 86

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VERTEBRAE AND SPINAL

CORD/NERVES

Vertebrae

Vertebral Foramen-passageway for the spinal

cord.

Intervertebral foramen- sides of the vertebral

column, where the spinal nerve roots exit the

vertebral canal COLOR BK PG 25

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Peripheral Nervous System

The part of the nervous system outside of the

vertebral column:

Cranial Nerves

Spinal Nerves

Peripheral Nervous System

Cranial Nerves have origin in the brain.

They are sensory nerves, motor nerves or

mixed.

Sensory- I, II, VIII,

Motor- III, IV, VI, XI, XII

Mixed V, VII, IX, X

COLOR BK PG 83

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Peripheral Nervous System

The cranial nerves are:

1.CN I - Olfactory Nerve

2.CN II - Optic Nerve

3.CN III - Oculomotor Nerve

4.CN IV - Trochlear Nerve

5.CN V - Trigeminal Nerve

6.CN VI - Abducens Nerve

7.CN VII - Facial Nerve

8.CN VIII - Vestibulocochlear Nerve

9.CN IX - Glossopharyngeal Nerve

10.CN X - Vagus Nerve

11.CN XI - Spinal Accessory Nerve

12.CN XII - Hypoglossal Nerve

Oh

Oh

Oh

To

Touch

And

Feel

Very

Good

Velvet

Such

Heaven

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Spinal Nerves

There are 31 pairs of spinal nerves.

8 cervical-exit above their vertebrae

12 thoracic-exit below their vertebrae

5 lumbar

5 sacral

1 coccygeal

COLOR BK PG 86

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Spinal Nerves

Plexuses- network of nerves

Root/Trunk/Cord/Peripheral nerves

COLOR BK PG 87

Another Brachial Plexus Picture

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Terminal Nerves

Let’s Build the Brachial Plexus

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Spinal Nerves

There are 3 plexuses

Cervical Plexus- make up C1-C4

Brachial Plexus- make up C5-T1

Lumbosacral Plexus- make up L1-S5

COLOR BK PG 87

Spinal Nerves

FUN FACT!

Most muscles are inervated by at least 2

spinal nerves so loss of function will not

occur, likely the muscle will weaken

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Spinal Nerves

FUN FACT!

Significant levels

C3- damage here or above would affect

function of the diaphragm. Need assistance

with breathing.

C5- damage from here down would result in

loss of upper extremity function.

Spinal Nerves

Dermatomes- COLOR BK PG 89

Area of skin supplied with the sensory fiber of

a spinal nerve.

Most areas have overlap, so total anesthesia

will not occur unless 2 nerves lose function.

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Spinal Nerves