Transcript File

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
Circulation of the
CSF
•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
Neuronal Organization
Neural Organization: Pathways
•A neural pathway is comprised of centers/cell bodies and tracts
• 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)
Major Regions of the Brain
Figure 15.1 Major Divisions of
the Brain
Major Regions of the Brain
Major Regions and Landmarks
• 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
–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.
Central sulcus
Parietal lobe
Occipital lobe
Frontal lobe
Insula
Retracted
temporal lobe
(c)
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
VIII
IX
X
XII
-associated with 5 pairs of
cranial nerves
VIII , IX, X, and XII
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
BRAIN STEM
= “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)
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”
Major Parts of the Brain
44
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
Foramen
magnum
Cervical
enlargement
Cervical
enlargement
Spinal cord
Vertebral
canal
Lumbar
enlargement
Lumbar
enlargement
Conus
medullaris
Conus
medullaris
Cauda
equina
Filum
terminale
(a)
(b)
• 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 Cord
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
Fasciculus gracilis
Dorsal column
Fasciculus cuneatus
Posterior spinocerebellar tract
Lateral corticospinal tract
Lateral reticulospinal tract
Rubrospinal tract
Anterior spinocerebellar tract
Lateral spinothalamic tract
Anterolateral
system
Anterior spinothalamic tract
Anterior reticulospinal tract
Medial reticulospinal tract
Anterior
corticospinal
tract
General Components of a Spinal Reflex
Spinal cord
Interneuron
Dorsal
1
Receptor
3
2
Sensory neuron
Cell body
of sensory
neuron
White matter
Gray matter
4
Ventral
Motor neuron
5
Effector
(muscle
or gland)
(b)
Central
canal
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
Fascicle
Peripheral nerve
Epineurium
Motor neuron
ending
Axon
Perineurium
Endoneurium
Node of Ranvier
Schwann cell
Sensory receptor
Myelin sheath
Neurilemma
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
Olfactory (I)
Olfactory tract
Optic (II)
Optic tract
Oculomotor (III)
Trochlear (IV)
Trigeminal (V)
Vestibulocochlear (VIII)
Abducens (VI)
Hypoglossal (XII)
Facial (VII)
Vagus (X)
Glossopharyngeal (IX)
Accessory (XI)
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)
C1
C2
C3
C4
C5
C6
C7
C8
T1
T2
T3
T4
Posterior
view
Cervical
nerves
T5
T6
T7
Thoracic
nerves
T8
T9
T10
T11
T12
L1
Cauda equina
L2
L3
L4
L5
S1
S2
S3
S4
S5
Co
Lumbar
nerves
Sacral
nerves
Coccygeal
nerve
Spinal Nerves
• Ventral root (aka
anterior root)
• Motor root
• Axons of motor
neurons whose cell
bodies are in the
spinal cord
Dorsal root
Ventral branch
of spinal nerve
Dorsal root
ganglion
Dorsal root
Ventral root
Posterior
median sulcus
Paravertebral
ganglion
Posterior
horn
(b)
Lateral horn
• Spinal nerve
• Union of ventral
root and dorsal
roots
• Hence we now
have a “mixed”
nerve
Dorsal branch
of spinal nerve
Anterior
horn
Central
canal
Anterior
median fissure
Ventral root
(a)
Visceral branch
of spinal nerve
Ventral branch
of spinal nerve (ventral ramus)
Dorsal branch
of spinal nerve (dorsal ramus)
Spinal nerve
Paravertebral
ganglion
Visceral branch
of spinal 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
Posterior view
Musculocutaneous
nerve
Axillary nerve
Radial nerve
Median nerve
Ulnar nerve
Phrenic nerve
Cauda equina
Femoral
nerve
Obturator nerve
Sciatic nerve
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
S1
S2
S3
S4
S5
Co
Cervical plexus
(C1–C4)
Brachial plexus
(C5–T1)
Intercostal
nerves
Lumbosacral plexus (T12–S5)
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)
Interneurons
• Preganglionic fibers
• Axons of preganglionic
neurons
• Neuron cell bodies in
CNS
• Postganglionic fibers
• Axons of postganglionic
neurons
• Neuron cell bodies in
ganglia
Dorsal root ganglion
Dorsal root
ganglion
Sensory
neuron
Sensory
neuron
Spinal cord
Autonomic
ganglion
Preganglionic
fiber
Somatic motor neuron
Postganglionic
fiber
Viscera
Skin
Skeletal
muscle
(a) Autonomic pathway
(b) Somatic 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
Spinal cord
Ventral root
Sympathetic
trunk
Paravertebral
sympathetic
ganglion
Dorsal root
Dorsal root
ganglion
Pia mater
Arachnoid
mater
Spinal nerves
Dura
mater
Transverse
process
Vertebral notch
(forms part of
intervertebral
foramen)
Body of
vertebra
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
Preganglionic
neuron
Gray
ramus
Dorsal root
ganglion
Postganglionic
neuron
Spinal cord
Dorsal root
Posterior horn
White
ramus
Sympathetic trunk
Lateral horn
Dorsal branch of
spinal nerve
Anterior horn
Ventral root
Spinal
nerve
Ventral branch of
spinal nerve
Paravertebral
sympathetic
ganglion
Visceral effector
(intestine)
Collateral
ganglion
To visceral effectors
(smooth muscle
of blood vessels,
arrector pili
muscles, and
sweat glands)
Sympathetic Division
Lacrimal gland
Eye
Parotid gland,
submandibular and
sublingual glands
Blood vessels
Heart
Celiac and
pulmonary
plexuses
Trachea
Lungs
Celiac
ganglion
Skin
Fibers to
skin, blood vessels,
and adipose tissue
Superior
mesenteric
ganglion
Liver
Gallbladder
Stomach
Pancreas
Small intestine
Spinal
cord
Inferior
mesenteric
ganglion
Sympathetic
chain ganglia
Preganglionic
neuron
Large intestine
Adrenal gland
Kidney
Urinary
bladder
Postganglionic
neuron
Ovary
Uterus
Penis
Scrotum
Parasympathetic Division
• Craniosacral division –
location of preganglionic
neurons
• Ganglia are near or
within various organs
• Terminal ganglia
• Preganglionic fibers of the
head are included in nerves
III, VII, and IX
• Preganglionic fibers of
thorax and abdomen are
parts of nerve X
• Short postganglionic
fibers
• Continue to specific
muscles or glands
70
Parasympathetic Division
Sphenopalatine
ganglion
Cranial
nerve III
Ciliary ganglion
Submandibular
ganglion
Cranial
Nerve VII
Cranial
nerve IX
Lacrimal
gland
Otic ganglion
Eye
Submandibular
and sublingual glands
Parotid
gland
Heart
Cranial nerve X
(Vagus)
Trachea
Lung
Cardiac and
pulmonary
plexuses
Liver
Gallbladder
Celiac
plexus
Stomach
Spleen
Pancreas
Superior
hypogastric
plexus
Small intestine
Inferior
hypogastric
plexus
Spinal
cord
Large intestine
Kidney
Pelvic
nerves
Preganglionic
neuron
Postganglionic
neuron
Urinary
bladder
Scrotum
Penis
Uterus
Ovary