Big Horn SheepGlacier National Park

COMPONENTS OF THE NERVOUS SYSTEM

Peripheral Nervous System (PNS) Central Nervous System (CNS)

Brain & Spinal CordSomatic Cranial Nerves Autonomic(Visceral)

31 Pairs of Spinal Nerves

12 Pairs of Cranial Nerves

Sympathetic Parasympathetic

TYPES OF NEURONS

Myelin

Myelin

Myelin

Motor - Efferent Sensory - Afferent Sensory - Afferent

NERVOUS SYSTEM TERMINOLOGY

Ganglion – Collection of Cell Bodies outside the CNS.

Four Types of Ganglia:1. Dorsal Root

2. Paravertebral 3. Prevertebral PNS 4. Enteric

Motor Neuron – EfferentGeneral Somatic Efferent (GSE) – Spinal NerveGeneral Visceral Efferent (GVE) – Autonomic Nerve

Sensory Neuron – AfferentGeneral Somatic Afferent (GSA) – Spinal NerveGeneral Visceral Afferent (GVA) – Autonomic Nerve

Nucleus/Horn – Collection of Cell Bodies.

CNS White Matter – Collection of Myelinated Nerve Fibers.

Gray Matter – Collection of Un-myelinated Dendrites and Cell Bodies.

Dorsal Root

Dorsal Rootlets

* Dorsal Root Ganglion

Ventral RootletsVentral Root

Dorsal Ramus

Ventral Ramus

Spinal Nerve

COMPONENTS OF A SPINAL NERVE

Dorsal Horn Gray Matter

Ventral Horn Gray Matter

*

SOMATIC REFLEX ARC

Spinal Nerve

Dorsal RootAfferent neurons only

Dorsal Root Ganglion

Ventral Horn

– Cell Bodies

Dorsal Horn

12

3

4

Ventral RootEfferent neurons only

1. Temperature2. Pain3. Touch4. proprioception

Skeletal Muscle

Synapse of Lower Motor with Upper Motor Neuron

Central LesionContralateral loss

Lower Motor Neuron

Decussation in MedullaSite of Crossover

Cerebral CortexPre-Central Gyrus

Upper Motor Neuron

CORTICOSPINAL TRACT MOTOR

Spinal Cord Lesion Epsilateral loss

Cerebral CortexPost Central Gyrus

Decussation in Medulla

Thalamus

1st Order Neuron 2nd Order Neuron

2st Order Neuron

3rd Order Neuron3rd Order Neuron

PAIN, TEMPERATURE & TOUCH

PROPRIOCEPTION, VIBRATION & DISCRIMINATING TOUCH

SPINOTHALAMIC TRACTS - SENSORY

1st Order Neuron

Central LesionContralateral loss

Central LesionContralateral loss

Spinal Cord Lesion Epsilateral loss below lesion

Spinal Cord Lesion Contralateral loss below lesion

DERMATOMES

AUTONOMIC NERVOUS SYSTEM

PARASYMPATHETIC

GlandsCardiac muscle – heartSmooth muscle – organs

Craniosacral Outflow

SYMPATHETIC

Glands – sweatCardiac muscle – heartSmooth muscle – organs, blood vessels & hair

Thoracolumbar Outflow

PRE- AND POST-GANGLIONIC NEURONS

Lateral Horn

3 - Preganglionic neuron

4 – Postganglionic neuron

VISCERAL REFLEX ARC

Lateral Horn

Cell Body of Visceral Afferent In Dorsal Root Ganglion 1 - Receptor2 - Visceral Afferent

3 - Preganglionic neuron

4 – Postganglionic neuron 5 - Effector:

Smooth muscleGland

SYMPATHETIC TRUNK

Dorsal Root Ganglion

General Somatic Efferent Nerve (GSE)

Cell Bodies

Dorsal Root of Spinal Nerve

Ventral Root of Spinal Nerve

Anterior Horn

Ventral Ramus

Dorsal Ramus

General Somatic Afferent Nerve (GSA)

Spinal Nerve

SPINAL NERVE C1 – Cocc 1

Spinal Nerve

Sympathetic Truck

Ventral Ramus

Gray Ramus Communicans

White Ramus Communicans

Paravertebral Ganglion

ADD THE SYMPATHETIC TRUNK TO SPINAL NERVES T1 – L2

Spinal Nerve

Lateral Horn

SYMPATHETIC DISTRIBUTION TO SPINAL NERVES T1-L2

Dorsal Root Ganglion

GVA Nerve

Postganglionic Nerve (GVE)

Preganglionic Nerve (GVE)

White Ramus Communicans

Paravertebral Ganglion

Gray Ramus Communicans

Cell Bodies

Dorsal Root of Spinal Nerve

Ventral Root of Spinal Nerve

Lateral Horn

Sympathetic Truck

Ventral Ramus

Dorsal Ramus

1st Way

T1-L2

SYMPATHETIC DISTRIBUTION TO SPINAL NERVES T1-L2

Dorsal Root Ganglion

GVA Nerve

Postganglionic Nerve (GVE)

Preganglionic Nerve (GVE)

White Ramus Communicans

Cell Bodies

Dorsal Root of Spinal Nerve

Lateral Horn

Paravertebral Ganglion

Gray Ramus Communicans

Ventral Root of Spinal Nerve

Dorsal Ramus

Ventral Ramus

Paravertebral Ganglion

Sympathetic Truck

2nd Way

T1-L2

SYMPATHETIC DISTRIBUTION TO SPINAL NERVES T1-L2

Dorsal Root Ganglion

GVA Nerve

Postganglionic Nerve (GVE)

Preganglionic Nerve (GVE)

Cell Bodies Dorsal Root of

Spinal Nerve

Paravertebral Ganglion

Gray Ramus Communicans

Ventral Root of Spinal Nerve

White Ramus Communicans

Dorsal Ramus

Ventral Ramus

Sympathetic Trunk

Lateral Horn

3nd Way

T1-L2

Spinal Nerve

Gray Ramus Communicans ONLY

Sympathetic Truck

Ventral Ramus

ADD THE SYMPATHETIC TRUNK TO SPINAL NERVES C1 – C8

Paravertebral Ganglion

Gray Ramus Communicans

SYMPATHETIC DISTRIBUTION TO SPINAL NERVES C1-C8

Preganglionic Nerve (GVE)

Postganglionic Nerve (GVE)

GVA Nerve

Cell Bodies

Dorsal Ramus

Ventral Ramus

Ventral Root of Spinal Nerve

Dorsal Root of Spinal Nerve

Paravertebral Ganglion

Dorsal Root Ganglion

White Ramus Communicans

Sympathetic Trunk

Lateral Horn

T1-T2

C1-C8

CERVICAL SYMPATHETIC CHAIN GANGLIA

Spinal Nerve

Gray Ramus Communicans ONLY

Sympathetic Truck

Ventral Ramus

ADD THE SYMPATHETIC TRUNK TO SPINAL NERVES L3 – Cocc 1

Paravertebral Ganglion

SYMPATHETIC DISTRIBUTION TO SPINAL NERVES L3-Cocc 1

Preganglionic Nerve (GVE)

Postganglionic Nerve (GVE)

GVA Nerve

Cell Bodies

Sympathetic Trunk

Dorsal Ramus

Ventral Ramus

Ventral Root of Spinal Nerve

Dorsal Root of Spinal Nerve

Paravertebral Ganglion

Dorsal Root Ganglion

Gray Ramus Communicans

White Ramus Communicans

Lateral Horn

L1-L2

L3-Cocc 1

12 PAIRS OF CRANIAL NERVES CN I Olfactory

CN II Optic

CN III Oculomotor

CN IV Trochlear

CN V Trigeminal

CN VI Abducens

CN VII Facial

CN VIII Vesticulocochlear

CN IX Glossopharyngeal

CN X Vagus

CN XI Accessory

CN XII Hypoglossal

Parasympathetic

M – MotorS – SensoryB – Both

S

S

M

M

B

M

B

S

B

B

M

M

The End