THE NERVOUS

SYSTEM

Dr. Nabil Khouri

Divisions of

the nervous

system

Protection of the Brain:

The Cranial Meninges

• Cranium is covered with

protective membranes called

Meninges

– Cranial meninges are

continuous with spinal

meninges ) composed of 3

layers) :

– 1. An outer, fibrous dura

mater – forms sheets (falx)

that separate the cerebrum

and the cerebellum into the

hemispheres and the

cerebellum from the

cerebrum

– comprised of an outer

endosteal layer and an inner

meningeal layer

2. middle Arachnoid mater –

avascular layer

– named for the spider-like

struts (trabeculae) that

connect the Arachnoid to the

underlying Pia mater

3. inner, thin Pia mater – vascular

connective tissue

– makes direct contact with

brain tissue

– cells of the Pia mater are

impermeable to the passage of

many substances

– this membrane is pierced by

tiny capillaries that nourish

the brain tissue – arise from

the larger capillaries that

travel within the Dura mater

•large spaces for the circulation

of blood can be found between the

two dural layers called Sinuses

e.g. superior sagittal sinus

• also large veins run through the

subarachnoid space

e.g. cerebral veins

There are spaces between these

membranes

A. Subarachnoid space: between the

arachnoid and pia maters for the

circulation of CSF

B. Subdural space: between the

arachnoid and the dura mater

C. Epidural space – between the dura

mater and the vertebral canal in the spinal

column

Protection of the Brain: CSF – CSF: 80 to 150 mL of clear, colorless liquid

• Replaced completely up to three times per day

• Components : glucose, proteins, lactic acid, urea, ions

• Made by specialized cells in the lateral ventricles – Choroid plexus

– Are networks of capillaries in the walls of the ventricles

– Covered by ependymal cells (epithelialcells) that filter the blood plasma and produce CSF by secreting it

– These cells are capable of allowing passage of certain substances from the blood through them into the CSF – inhibit the passage of others

• Continually circulates through ventricles of the brain and central canal to subarachnoid space

• functions:

• 1. Chemical protection: provides an optimal chemical environment for neuronal signaling

• 2. Mechanical protection: acts as a shock absorber, preventing direct physical contact between brain tissue and the bones of the cranium or vertebral canal

• 3. Circulation: allows the exchange of nutrients and waste products between the blood and nervous tissue

CSF formation • -CSF forms in the choroid plexi of the lateral ventricles and

flows into the 3rd ventricle through the interventricular

foramina

• -the 3rd ventricle adds to the CSF volume

• -the CSF then flows into the 4th ventricle via and cerebral

aqueduct (passes through the midbrain) – contributes more

volume

• -then enters the subarachnoid space via openings in the 4th

ventricle called apertures

• -also enters the central canal of the SC

• -circulation is driven by ciliary action and pressures provided

by the blood and gravity – 10 mm Hg

•CSF is gradually reabsorbed into

the blood through fingerlike

projections into the dural venous

sinuses called : Arachnoid

granulations

-absorbed at about 20ml/hr which

equals its rate of formation

•interfering with the drainage of

CSF

into the subarachnoid space can

result in accumulation of CSF in

the ventricles & CSF pressure rises

= hydrocephalus

Circulation of the

CSF

Neuronal Organization

• Sensory pathway

– Ascending

– Information from sensory receptors to CNS

• Motor pathway

– Descending

– Information from CNS to skeletal muscle or glands

– Direct pathways – cause precise, voluntary movements

– Indirect pathways – result in involuntary movement (from brain

stem)

Neural Organization: Pathways

•A neural pathway is comprised of centers/cell bodies and tracts

Figure 15.1 Major Divisions of

the Brain

Major Regions of the Brain

Major Regions of the Brain

• Cerebrum = largest portion

-left and right cerebral hemispheres divided by the longitudinal fissure

-connected by the corpus callosum

-folded into ridges and grooves: ridges are caled Gyri (gyrus) and the grooves

are called Sulci

-sulci divide the cerebrum into lobes

Major Regions and Landmarks

–Central sulcus

•Frontal and parietal lobes

Lobes of the Cerebrum

• Five (5) lobes bilaterally:

• Frontal lobe

• Parietal lobe

• Temporal lobe

• Occipital lobe

• Insula aka „Island of

Reil‟

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

(c)

Parietal lobe

Central sulcus

Occipital lobe

Frontal lobe

Insula

Retracted

temporal lobe

Functions of the Cerebral Lobes

The Cerebrum Cerebrum is comprised of:

1. white matter - neurons with

long, myelinated axons

-organized into tracts

A. Association tracts: conduct

impulses between gyri within

a hemisphere

B. Commisural tracts: connects

gyri in one hemisphere to

others in the other hemisphere

1. corpus callosum

2. anterior commisure

3. posterior commisure

C. Projection tracts: tracts that

connect cerebrum to the lower

parts of the CNS (e.g. Thalamus,

brainstem)

2. gray matter – outer edge of the

cerebrum = cerebral cortex (2-4 mm

thick = billions of neurons)

-localized areas of gray matter

called the basal ganglia

Major Regions and Landmarks

-area for specific processing of

sensation-area of voluntary

movement, speech

-areas for all “higher order”

functions

Cortex is comprised of primary and

association areas

e.g. primary visual, auditory &

gustatory areas

e.g. primary motor area (precentral

gyrus

-primary areas – areas where “raw”

information is first received and raw

commands are generated

- association areas for integration and

analysis of incoming info & help in

making of “decisions”

Basal Ganglia

-nuclei found deep within the cerebrum

- receives input from the cortex & provides output to

the motor areas of the cortex via the thalamus

-integrates motor commands provided by the

cerebral cortex

-regulates the initiation & termination of muscle

movement.

-anticipates body movements & controls

subconscious contraction of skeletal muscle

• comprised of the:

• 1. Corpus striatum

– caudate nucleus: controls

movement of arms and legs

when walking

– putamen: precedes or

anticipates body

movements

– nucleus accumbens

• 2. globus pallidus: regulates

muscle tone for movements

• 3. Corpus claustrum:

receives visual information

• 4. substantia nigra: high

concentration of dopanergic

neurons

• 5. subthalmic nucleus

Major Regions and Landmarks

• Diencephalon: Includes the

thalamus, hypothalamus,, epithalamus

and subthalamus

The thalamus: 80% of the

diencephalon

• paired oval masses of gray

matter organized into nuclei,

interspersed with white matter

• joined by the intermediate

mass (gray matter) in about

70% of brains

• major relay station for most

sensory impulses from the SC,

brain stem

• crude perception of pain, heat

and pressure (refined in

cerebrum)

• transmits motor information

from cerebellum to the

cerebrum

Hypothalamus •Emotions, autonomic

functions, hormone

production

•major functions:

•1. Control of the ANS –

integrates signals from the

ANS (regulated smooth and

cardiac muscle contraction)

major regulator of visceral

activities (heart rate, food

movements, contraction of

bladder)

•2. Produces hormones &

connects with pituitary to

regulate its activity

•-releasing hormones

•-oxytocin

•-vasopressin

3. regulates emotional and behavioral patterns – rage,

aggression, pain and pleasure + sexual arousal

4. regulates eating & drinking – hypothalamus contains

a thirst center which responds to a rise in osmotic

pressure in the ECF (dehydration)

5. controls body temperature – monitors temp of blood

flowing through the hypothalamus

Epithalamus – consists of the pineal gland and habenular nuclei

-pineal gland – part of the endocrine system

-secretes the hormone melatonin

-increased secretion in dark

-promote sleepiness and helps set the circadian

rhythms of the body (awake/sleep period)

Subthalamus – works with the cerebrum and cerebellum to control

body movements

-majority is made of the subthamic nuclei

-sends efferent connections to the caudate nucleus and

putamen, to the medial and lateral nuclei of the thalamus and to the

red nucleus and substantia nigra of the midbrain -also receives

afferent connections from the substantia nigra

Cerebellum

Cerebellum – divided into hemisphere with lobes -

like the cerebrum

• anterior and posterior lobes

– involuntary motor activities

• evaluates and coordinates motor activities initiated by the cerebrum and corrects problems by sending info back to the cerebrum

• regulate posture & balance

– has a superficial layer of gray matter called the cerebellar cortex - like the brain

– deep to the gray matter are tracts of white matter = arbor vitae

– also has nuclei = cerebellar nuclei (origin of neurons that connect the cerebellum to the brain and SC)

– connected to the brain stem by three cerebellar peduncles

• inferior – sensory information from the inner ear and body proprioceptors into the cerebellum

• middle – carry motor commands for voluntary movements that originated in the cortex into the cerebellum for coordination of muscle movement

• superior – connects to the red nuclei and the nuclei of the thalamus

Midbrain

Major Regions and Landmarks

-associated with 5 pairs of

cranial nerves

VIII , IX, X, and XII

XII

X

IX

VIII

BRAIN STEM

• Medulla oblongata • Contains several nuclei also that

regulate autonomic functions - reflex

centers for regulating heartbeat and

BP (cardiovascular center),

respiration (respiratory center), plus

vomiting, coughing, sneezing, and

swallowing

– nuclei in the posterior part are

associated with sensations of

touch, proprioception, pressure

and vibration

– Inferior olivary

– Gracile

– Cuneate nucleus

Gray matter -nuclei:

Reflex centers – e.g. cardiovascular & respiratory

1. Inferior olivary: part of the olive

proprioceptors to the cerebellum – joint and muscle position

2. Gracile: ascending sensory tracts from SC synapse here -relayed into the thalamus

-proprioception and touch from lower limbs

3. Cuneate: ascending sensory tracts from Spinal cored synapse here –relayed into the

thalamus

-prioprioception and touch from upper limbs

– white matter

– contains sensory/ascending and motor/descending tracts

– some of the white matter form bulges called pyramids – white tracts

that connect the cerebrum to the Spinal Cord

• Pons = “bridge”

- superior to the medulla and anterior to the cerebellum

- connects the brain stem to the cerebrum

– consists of nuclei connected by tracts

• Pontine nuclei – control voluntary movements that originate in the cerebral cortex and are relayed through the pons into the cerebellum

• Pneumotaxic area – controls breathing (with medulla)

• Apneustic area – controls breathing (with medulla)

BRAIN STEM

Midbrain (Mesencephalon)

Relay station between the cerebrum and the spinal cord, relay station with the cerebellum, controls visual reflexes & releases dopamine

– extends from the pons to the diencephalon

– relays motor tracts into the SC, medulla and pons & conducts sensory tracts into the thalamus

– Anterior portion contains a pair of white tracts = cerebral peduncles

• Connects the cerebrum to the brain stem (motor)

– Posterior portion = tectum

• white matter tracts = cerebellar peduncles (motor & sensory info)

• four round elevations = superior and inferior colliculi

• reflex centers for visual activities (tracking, scanning) pupillary reflex, shape of the lens

• reflexes that mediate movements of the eyes, head and neck - the startle reflex

• relays impulses from hearing receptors to the thalamus

• -generates involuntary somatic motor responses

• release of dopamine from substantia nigra (nuclei) - loss of these neurons =

Parkinsons

• red nuclei forms synapses with cerebellum to coordinate muscle movements

Midbrain nuclei

• colliculi – superior and inferior

– Visual reflex centers

• red nuclei

– Connects the cerebellum to the motor cortex of the cerebrum

– Connects the motor areas of the cerebrum to outgoing motor neurons for

posture and balance

• substantia nigra

– Dopamine release

• White matter tracts: cerebral peduncles, cerebellar peduncles

I - Olfactory

II - Optic

III - Oculomotor

IV-Trochlear

V - Trigeminal

VI - Abducens

VII - Facial

VIII - Acoustic

IX - Glossopharyngeal

X - Vagus

XI - Accessory

XII - Hypoglossal

-cranial nerves – 12 pairs

-considered part of the peripheral nervous system (PNS)

-olfactory & optic contain only sensory axons = sensory nerves

-remaining are either motor or mixed nerves – both motor and sensory axons

“some say my mother bought my brother some bad beer, my my”

44

Major Parts of the Brain

Spinal Cord

• Slender column of

nervous tissue continuous

with brain and brainstem

• Extends downward

through vertebral canal

• Begins at the foramen

magnum and terminates at

the first and second lumbar

vertebrae (L1/L2)

interspace

Brainstem

Spinal cord

(a) (b)

Foramen

magnum

Cervical

enlargement

Vertebral

canal

Lumbar

enlargement

Conus

medullaris

Cauda

equina

Filum

terminale

Conus

medullaris

Lumbar

enlargement

Cervical

enlargement

Spinal Cord • length in adults = 16 to 18

inches

• Cervical and lumbar

enlargements

– cervical = C4 to T1, nerves to and

from upper limbs

– lumbar = T9 to T12, nerves to and

from lower limbs

• Tapers to conus medullaris

• filium terminale extension of the

pia mater that anchors the SC to the

coccyx

• 31 segments each with

– Dorsal root ganglia

• Sensory neuron cell bodies

– Pair of dorsal roots

– Pair of ventral roots

Spinal Meninges

• Specialized membranes

• Provide physical stability and shock absorption

• Three layers – Dura mater = dense irregular CT

• continuous with the brain‟s DM

• above it is the epidural space

– Arachnoid = continuous with brain • above it is the subdural space

• below is the subarachnoid space

• avascular

– Pia mater = connective tissue • collagen and elastin bundles

• well vascularized

• The Pia Mater

– Innermost meningeal layer

– Bound firmly to underlying tissue

– Denticulate ligaments bind pia mater to the arachnoid

-spinal tap: under local anesthetic

-long needle is inserted into the

subarachnoid space and CSF is

withdrawn or antibiotics or

anesthetics are given

-given between L3 & L4 or

L4 & L5

Histology of the Spinal Cord

• Central gray matter

– Contains cell bodies of neurons and glial cells + unmyelinated

axons

– Gray matter projections are horns

• Peripheral white matter

– Myelinated and unmyelinated axons

– Tracts or columns

Organization of Gray Matter

• Posterior gray horns

– Somatic and visceral sensory nuclei

• Anterior gray horns

– Somatic motor control

• Lateral gray horns

– Visceral motor neurons

• Gray commissures

– Axons of interneurons crossing cordated and unmyelinated axons

Organization of

White Matter

• Six columns (funiculi)

– Anterior, lateral and posterior

white columns

– Contain tracts

• Ascending tracts relay

information from spinal

cord to brain

• Descending tracts carry

information in the

opposite direction

Posterior spinocerebellar tract

Lateral corticospinal tract

Lateral reticulospinal tract

Rubrospinal tract

Anterior spinocerebellar tract

Lateral spinothalamic tract

Anterior reticulospinal tract

Medial reticulospinal tract

Fasciculus cuneatus

Fasciculus gracilis

Dorsal column

Anterior spinothalamic tract

Anterolateral

system

Anterior

corticospinal

tract

General Components of a Spinal Reflex

Receptor

Sensory neuron

Motor neuron

White matter

Gray matter

Spinal cord

Dorsal Interneuron

4

5

3

2

1

(b)

Cell body

of sensory

neuron

Effector

(muscle

or gland)

Central

canal

Ventral

Medical Application: Alzheimer’s Disease

-loss or reasoning, memory

-11% of population over 65 (4 million people)

-unknown cause – thought to be genetic factors + environmental &

lifestyle

-neuronal plasma membranes contain a protein = amyloid precursor protein (APP)

abundant in presynaptic axon terminals

-cleavage of APP yields a secreted product = sAPPa that is secreted by the

presynaptic terminals normally

-if APP is cleaved at the wrong site – beta-amyloid

-two forms of beta-amyloid are possible based on cleavage site – the longer

form (Ab40) is harmless

-but the form Ab42 – 10% of the cleaved b-amyloid – aggregates to form

plaques and is neurotoxic

-underlying causes for Ab plaque formation remain unknown

-about 15% of cases appear to have a genetic link – familial Alzheimer‟s

-mutations in 3 genes: prenisilin-1, -2 and APP lead to early onset forms

(less the 15% of all cases) – prenisilins cleave APP

-mutations in these genes can shift the balance of b-amyloid to the harmful form,

-so can age

-also mutations in gene coding for apolipoprotein E (ApoE) a protein that helps transport

cholesterol in the blood

-may account for 85% of the cases – late-onset Alzheimers

-mutated genes for apoE = apoE4 – may increase risk of development

-may predispose you to Ab plaque formation, or may hasten the onset - ?????

Peripheral Nervous System

• Cranial nerves arising from the brain

• Somatic fibers connecting to the skin and skeletal muscles

• Autonomic fibers connecting to viscera

• Spinal nerves arising from the spinal cord

• Somatic fibers connecting to the skin and skeletal muscles

• Autonomic fibers connecting to viscera

Structure of a Peripheral Nerve

Peripheral nerve

Epineurium

Axon

Neurilemma

Myelin sheath

Schwann cell

Node of Ranvier

Endoneurium

Perineurium

Fascicle

Sensory receptor

Motor neuron

ending

Nerve and Nerve Fiber Classification

• Sensory nerves

• Conduct impulses into brain or spinal cord

• Motor nerves

• Conduct impulses to muscles or glands

• Mixed (both sensory and motor) nerves

• Contain both sensory nerve fibers and motor nerve fibers

• Most nerves are mixed nerves

• ALL spinal nerves are mixed nerves (except the first pair)

Nerve Fiber Classification

• Special somatic efferent (SSE) fibers

• Carry motor impulses from brain to muscles used in

chewing, swallowing, speaking and forming facial

expressions

• Special visceral afferent (SVA) fibers

• Carry sensory impulses to brain from olfactory and taste

receptors

• Special somatic afferent (SSA) fibers

• Carry sensory impulses to brain from receptors of sight,

hearing and equilibrium

Cranial Nerves

Olfactory bulb

Hypoglossal (XII)

Optic tract

Olfactory tract

Olfactory (I)

Optic (II)

Oculomotor (III)

Abducens (VI)

Facial (VII)

Glossopharyngeal (IX)

Accessory (XI)

Trochlear (IV)

Trigeminal (V)

Vestibulocochlear (VIII)

Vagus (X)

I - Olfactory

II - Optic

III - Oculomotor

IV-Trochlear

V - Trigeminal

VI - Abducens

VII - Facial

VIII - Acoustic

IX - Glossopharyngeal

X - Vagus

XI - Accessory

XII - Hypoglossal

-cranial nerves – 12 pairs

-considered part of the peripheral nervous system (PNS)

-olfactory & optic contain only sensory axons = sensory nerves

-remaining are either motor or mixed nerves – both motor and sensory axons

“some say my mother bought my brother some bad beer, my my”

Spinal Nerves

• ALL are mixed nerves

(except the first pair)

• 31 pairs of spinal nerves:

• 8 cervical nerves

• (C1 to C8)

• 12 thoracic nerves

• (T1 to T12)

• 5 lumbar nerves

• (L1 to L5)

• 5 sacral nerves

• (S1 to S5)

• 1 coccygeal nerve

• (Co or Cc)

Cauda equina

C1 C2 C3 C4 C5 C6 C7 C8 T1

T2

T3

T4

T5

T6

T7

T8

T9

T10 T11

T12

L1

L2

L3

L4

L5

S2 S3

S4

S1

S5 Co

Posterior

view

Cervical

nerves

Thoracic

nerves

Lumbar

nerves

Sacral

nerves

Coccygeal

nerve

Spinal Nerves

Lateral horn

Ventral root

(a)

(b)

Dorsal root

Dorsal root

Spinal nerve

Dorsal root

ganglion

Posterior

median sulcus

Posterior

horn

Anterior

horn

Central

canal

Anterior

median fissure

Dorsal branch

of spinal nerve

Ventral branch

of spinal nerve

Visceral branch

of spinal nerve

Paravertebral

ganglion

Ventral branch

of spinal nerve (ventral ramus)

Dorsal branch

of spinal nerve (dorsal ramus)

Paravertebral

ganglion

Visceral branch

of spinal nerve

Ventral root

• Ventral root (aka

anterior root)

• Motor root

• Axons of motor

neurons whose cell

bodies are in the

spinal cord

• Spinal nerve

• Union of ventral

root and dorsal

roots

• Hence we now

have a “mixed”

nerve

Nerve Plexuses

• Nerve plexus

• Complex networks formed by anterior branches of spinal nerves

• The fibers of various spinal nerves are sorted and recombined

• There are three (3) nerve plexuses:

• (1) Cervical plexus

• Formed by anterior branches of C1-C4 spinal nerves

• Lies deep in the neck

• Supply to muscles and skin of the neck

• C3-C4-C5 nerve roots contribute to phrenic nerves bilaterally

•(2) Brachial plexus

• Formed by anterior branches C5-T1

• Lies deep within shoulders

• (3) Lumbosacral plexus

• Formed by the anterior branches of L1-S5 roots

• Can be a lumbar (L1-L5) plexus and a sacral (S1-S5) plexus

• Extends from lumbar region into pelvic cavity

Plexuses

C1 C2 C3 C4 C5 C6 C7 C8 T1 T2 T3

T4 T5 T6

T8 T9 T10 T11 T12 L1 L2

L3 L4

L5

S2 S3 S4 S5

Co

Posterior view

Cervical plexus (C1–C4)

Lumbosacral plexus (T12–S5)

Sciatic nerve

Brachial plexus (C5–T1)

Obturator nerve

Phrenic nerve

Ulnar nerve Median nerve Radial nerve Axillary nerve

T7

S1

Cauda equina

Musculocutaneous

nerve

Femoral

nerve

Intercostal

nerves

Autonomic Nervous System

• Functions without conscious effort

• Controls visceral activities

• Regulates smooth muscle, cardiac muscle, and glands

• Efferent fibers typically lead to ganglia outside of the CNS

• Two autonomic divisions regulate:

• Sympathetic division (speeds up)

• Prepares body for „fight or flight‟ situations

• Parasympathetic division (slows down)

• Prepares body for „resting and digesting‟ activities

Autonomic Nerve Fibers

• All of the neurons are

motor (efferent)

• Preganglionic fibers • Axons of preganglionic

neurons

• Neuron cell bodies in

CNS

• Postganglionic fibers • Axons of postganglionic

neurons

• Neuron cell bodies in

ganglia

Interneurons

Spinal cord

Dorsal root ganglion

Viscera

(b) Somatic pathway

Skin

Somatic motor neuron

Dorsal root

ganglion

Sensory

neuron

Autonomic

ganglion

Preganglionic

fiber

Postganglionic

fiber

Skeletal

muscle

Sensory

neuron

(a) Autonomic pathway

Sympathetic Division • Thoracolumbar division –

location of preganglionic

neurons

• Preganglionic fibers leave

spinal nerves through white

rami and enter

paravertebral ganglia

• Paraverterbral ganglia

and fibers that connect

them make up the

sympathetic trunk

Ventral root

Spinal nerves

Spinal cord

Dorsal root

Pia mater

Sympathetic

trunk

Paravertebral

sympathetic

ganglion

Transverse

process

Vertebral notch

(forms part of

intervertebral

foramen)

Body of

vertebra

Dura

mater

Arachnoid

mater

Dorsal root

ganglion

Sympathetic Division • Postganglionic fibers extend from sympathetic ganglia to visceral organs

• Postganglionic fibers usually pass through gray rami and return to a spinal

nerve before proceeding to an effector

Spinal cord

Ventral root

Dorsal root

Sympathetic trunk Posterior horn

Lateral horn

Anterior horn

Preganglionic

neuron

Postganglionic

neuron

Dorsal root

ganglion

Spinal

nerve

Visceral effector

(intestine)

Collateral

ganglion

To visceral effectors

(smooth muscle

of blood vessels,

arrector pili

muscles, and

sweat glands)

Gray

ramus

White

ramus

Dorsal branch of

spinal nerve

Ventral branch of

spinal nerve

Paravertebral

sympathetic

ganglion

Sympathetic Division Lacrimal gland

Skin

Eye

Blood vessels

Heart

Lungs

Adrenal gland

Kidney

Uterus Penis

Liver

Stomach

Gallbladder

Pancreas

Ovary

Scrotum

Small intestine

Large intestine

Trachea

Parotid gland,

submandibular and

sublingual glands

Urinary

bladder

Preganglionic

neuron

Postganglionic

neuron

Sympathetic

chain ganglia

Inferior

mesenteric

ganglion

Spinal

cord

Superior

mesenteric

ganglion

Celiac

ganglion

Fibers to

skin, blood vessels,

and adipose tissue

Celiac and

pulmonary

plexuses

70

Parasympathetic Division

• Craniosacral division –

location of preganglionic

neurons

• Ganglia are near or

within various organs

• Terminal ganglia

• Short postganglionic

fibers

• Continue to specific

muscles or glands

• Preganglionic fibers of the

head are included in nerves

III, VII, and IX

• Preganglionic fibers of

thorax and abdomen are

parts of nerve X

Parasympathetic Division

Heart

Trachea

Lung

Gallbladder

Liver

Stomach

Spleen

Pancreas

Small intestine

Large intestine

Kidney

Uterus Scrotum

Otic ganglion

Ciliary ganglion Eye

Penis Ovary

Sphenopalatine

ganglion

Cranial

nerve III

Cranial

Nerve VII

Submandibular

ganglion

Cranial

nerve IX

Cranial nerve X

(Vagus)

Cardiac and

pulmonary

plexuses

Celiac

plexus

Superior

hypogastric

plexus

Inferior

hypogastric

plexus

Spinal

cord

Pelvic

nerves Urinary

bladder

Parotid

gland

Submandibular

and sublingual glands

Lacrimal

gland

Preganglionic

neuron

Postganglionic

neuron