Nervous System
SHANDONG UNIVERSITY
liu Zhiyu
Introduction
1.Divisions of nervous system
Central nervous system (CNS)
Peripheral nervous system (PNS):
(1) Central nervous system (CNS)
Brain :
Telencephalon
Diencephalon
Cerebellum
Midbrain
Pons
Medulla oblongata
Spinal cord
Brain
Stem
Introduction
(2) Peripheral nervous system (PNS):
Cranial n. (12 pairs)
Spinal n. (31 pairs)
Visceral n. :
Visceral sensory n.
Visceral motor n.:
Sympathetic part
Parasympathetic part
Introduction
2.
Basic terminology in nervous system:常用术语
(1) CNS:
1) Gray matter collection of
nerve cell bodies and their dendrites,
Cortex
the outer layer of gray matter
in cerebrum and cerebellum
Nucleus
A group of nerve cell bodies
which have the same shape
and function.
Introduction
2) White matter
collection of nerve fibers, white color during fresh condition
Medulla
a central core of white matter
beneath cortex of cerebrum
and cerebellum
Fasciculus ( tract ):
a bundle of nerve fibers
which have the same
origin, termination, and
function
Introduction
3) Reticular formation:
a field of intermingled grey and white matter , and with
larger or smaller groups of nerve cells occupying the meshes.
Introduction
(2) PNS
1) Ganglion:
a collection of neuron cell
bodies outside the CNS
2) Nerve:
a bundle of nerve fibers held
together by connective tissue
sheath
The Spinal
Cord
The Spinal Cord 脊髓
Position:

lies in vertebral canal

continuous with medulla
oblongata at level of
foramen magnum

ends at the lower border
of L1;

at birth , ends at
level of L3
the
The Spinal Cord
2. External features
＊ A long cylindrical structure
slightly flattened anteroposteriorly
＊ conus medullaris
＊ filum terminale
The Spinal Cord

Two enlargements
⑴ Cervical enlargement:
⑵ Lumbosacral enlargement

Fissure and sulci:
⑴ Anterior median fissure
⑵ Posterior median sulcus
⑶ Anterolateral sulcus
⑷ Posterolateral sulcus
The spinal cord
3. segments of spinal cord
A portion of the spinal cord that gives attachment to a pair of
spinal n. constitutes a segment.
31 segments :
Cervical segment 8
Thoracic segment 12
Lumbar egment 5
Sacral segment 5
coccygeal segment 1
The spinal cord
Table 1
Relationship of segments of spinal cord to vertebrae
Spinal segments
C1 ~ C4
Vertebral levels
Lie opposite the corresponding
vertebrae
C5~T4
T5 ~ T8
T9 ~T12
1 lower in number than
corresponding vertebrae
2 lower in number than
corresponding vertebrae
3 lower in number than
corresponding vertebrae
Lumber segments
T10~T12
Sacral and coccygeal segments
L1
The spinal cord
4. Internal structures
(1) Central canal
(2) Gray matter:
Anterior horn (column)
Posterior horn (column)
Intermediate zone
(3) White matter
Anterior funiculus
Lateral funiculus
Posterior. Funiculus
Ant. white commissure
The spinal cord
Gray matter
1) Posterior horn (column):
Posteromarginal nucleus
Substantia gelatinosa
Nucleus proprius
Nucleus thoracicus (dorsalis)
in segments
C8~L3
Gray matter
2) Intermediate zone
Intermediaolateral nucleus:
lies in segments T1~L3, containing
sympathetic preganglionic neurons


Sacral parasympathetic nucleus
lies in segments S2~S4

Intermediomedial nucleus
for sensation of viscera
Gray matter
3) Anterior horn (column): contain motor neurons
①α-motor neuron:
multipolar neuron
larger
②γ-motor neuron: smaller
neuron, innervates intrafusal
fibers regulating muscular tonus-
③ Renshaw’s cell:
Gray matter
3) Anterior horn (column):
Two groups of nuclei
① Medial nuclear group
present in most segments of
spinal cord, innervating axial
muscles.
② Lateral nuclear group
present only in cervical and
lumbosacral
enlargements,
innervating limb muscles
Gray matter
The laminas:
Spinal cord gray matter is arranged in layers, there are
10 Rexed’s lamina:
The posterior horn
formed by lamina Ⅰ to Ⅵ,
is
The intermediate zone
corresponding to lamina Ⅶ,
The anterior horn is
composed laminae Ⅷ and Ⅸ,
lamina Ⅹ is the gray matter
surrounding the central canal.
The spinal cord
Table 2. Important Subdivision of Spinal Cord Gray Matter
Region
Posterior horn
Intermediate zone
Lamina
Nucleus
Ⅰ
Marginal layer
Ⅱ
Substantia gelatinosa
Ⅲ, Ⅳ
Nucleus proprius
Ⅶ
Nucleus thoracicus (C8~L3)
Intermediolateral nucleus (T1~L3)
Sacral parasympathetic nucleus (S2~S4)
Intermediomedial nucleus
Anterior horn
Ⅸ
Motor neuron
White matter
Three kinds of fibers

Ascending fibers

descending fibers

fasciculus proprius
Ascending (Sensory) Pathways

Conduct general somatic sensory impulses
 Chains of neurons composed of:
– First-, second-, and third-order neurons
 three main ascending pathways
– Dorsal column pathway
– Spinothalamic pathway
– spinocerebellar pathway
Ascending tracts
Fasciculus gracilis
Fasciculus cuneatus
Posterior spinocerebellar
tract（）
Anterior spinocerebellar tract
Spinothalamic tract
Ascending tracts
Fasciculus Gracilis
Fasciculus Cuneatus
Conduct Proprioceptive
and fine touch sensation
Ascending tracts
Fasciculus gracilis
Fasciculus cuneatus
Carries sensations of
Two-point
discrimination
Proprioception
Pressure
Vibration
Ascending tracts
Fasciculus gracili
Arises from spinal ganglion cell
below T5 ；
Terminates the Gracile
nucleus
Fasciculus cuneatus
Arises from spinal ganglion cell
above T4；
Terminates the Cuneate nucleus
Ascending tracts
Spinothalamic Tract
Conduct Pain,
temperature and simple
touch sensation of
trunk and limbs
Origin:
Laminae Ⅰ,Ⅳ~Ⅶ of spinal cord
Termination:
Dorsal thalamus
Ascending tracts
Spinothalamic Tract
Conduct Pain,
temperature and simple
touch sensation of
trunk and limbs
Origin:
Laminae Ⅰ,Ⅳ~Ⅶ of spinal
cord
Termination:
Dorsal thalamus
Ascending tracts
Spinothalamic tracts
Lateral
Spinothalamic Tract
Carries pain and
temperature
information
Anterior
Spinothalamic Tract
Carries light touch,
pressure
Lateral
spinothalamic
Tract
Anterior
spinothalamic
Tract
Ascending tracts
Posterior.
Spinocerebellar
Origin: nucleus thoracicus
Termination: Cerebellum
Anterior.
Spinocerebellar
Origin:LaminaeⅤ~Ⅶ
Termination: Cerebellum
Carries subconscious
proprioceptive sensations to
cerebellum
dscending tracts
Corticospinal tract
Arises from the cerebral cortex
Terminates in the motor neurons of
spinal cord, it divided into two tract:
Lateral Corticospinal
Anterior corticospinal
dscending tracts 下行传导束
Lateral Corticospinal
Anterior corticospinal
Function: control somatic
voluntary movement
Rubrospinal Tract
Begins in the red nucleus, which is located at the
midbrain and synapse with lower motor neurons in the
Laminae Ⅴ~Ⅶ of the spinal cord.
Injury to this structure impairs forearm and hand
movements, but doesn’t greatly affect general body
movement
Vestibulospinal
Originate in the vestibular nuclei, and synapse with lower
motor neurons Laminae Ⅶ~Ⅷ of the of the spinal cord.
Receive major input from the vestibular nerve, and
the cerebellum
Laminae
Ⅶ~Ⅷ
② another descending tracts:
Reticulospinal
Longitudinal
fasciculus
Tectospinal
The spinal cord
② Descending tracts
Tracts
Lateral
Corticospinal
Anterior
corticospinal
Rubrospinal
origin
Cerebral cortex
Cerebral cortex
Red nucleus
Vestibulospinal vestibular nuclei
position
Lateral Funiculus
Ant. Funiculus
Lateral Funiculus
Ant. Funiculus
Termination
Laminae
Ⅳ~Ⅸ
Function
Voluntary mov.
Ant. horn
Laminae
Ⅴ~Ⅶ
Excite flexor
Laminae
Ⅶ~Ⅷ
Excite extensor
motor neurons
motor neurons
The spinal cord
② Descending tracts
Tracts
origin
position
Reticulospinal
Reticular
formation
Ant., lateral
Funiculus
Longitudinal
fasciculus
Vestibular
nuclei
Ant. Funiculus
Termination
Function
Laminae Ⅶ~Ⅷ
Voluntary mov.
LaminaeⅦ~Ⅷ
Condinate neck
with eye mov.
Tectospinal
Sup. colliculus Ant. Funiculus
LaminaeⅥ~Ⅷ
Spinal cordIntrinsic
③ Fasciculus
proprius
Spinal cord
Ant., pos. lateral
Funiculus
Spinal cord
reflex mechanism
of spinal cord
Ascending tracts
Tract
Site of origin
Fasciculus
gracilis
Spinal ganglia
below
segment T5
Fasciculus
cuneatus
Spinal ganglia
above
segment T4
Posterior
spinocerebellar
Homolateral
nucleus
thoracicus
Anterior
spinocerebellar
Spinothalamic
Funiculu
s
Termination
Gracile
nucleus
Posterior
Cuneate
nucleus
Lateral
Cerebellum
Contralateral
Laminae
Ⅴ~Ⅶ
Laminae Ⅰ,
Ⅳ~Ⅶ
Lateral
and
anterior
Dorsal
thalamus
Function
Convey
proprioceptive
and fine touch
sensation of
trunk and limbs
Unconscious
proprioception
from lower limb
and lower
portion of trunk
Pain,
temperature and
simple touch
sensation of
trunk and limbs
Descending tracts
Tract
Site of origin
Termination
Function
Cerebral cortex
Laminae Ⅳ~ Ⅸ
Voluntary
movement
Cerebral cortex
anterior horn
Rubrospinal
Red nucleus
Laminae Ⅶ~Ⅶ
Excitatory of
flexors
Vestibulospinal
Homolateral
vestibular nuclei
Laminae Ⅶ~Ⅷ
Excitatory of
extensors
Reticulospinal
Reticular formation Laminae Ⅶ~Ⅷ
Voluntary
movement
Fasciculus
proprius
Spinal cord
Intrinsic reflex
mechanism of
spinal cord
Lateral
corticospinal
Anterior
corticospinal
Spinal cord
Function of spinal cord

Conduction :
Convey afferent impulses to the brain;
conduct efferent impulses from the brain to
the effectors.

Reflexes ：the central of
the reflex arc.
Somatic reflex
stretch reflex
Visceral reflex
Reflex of bladder
Rectal emptying reflex
Rubrospinal
红核脊髓束
Two-Point Discrimination
Descending Motor Pathways
The spinal cord
① Ascending tracts:
Tract
Fasciculus
Gracilis
Fasciculus
Cuneatus
origin
Spinal ganglia
below T5
Spinal ganglia
above T4
position
Termination
Gracile nucleus
Posterior
Funiculus
Function
Proprioceptive
and fine touch
Cuneate nucleus sensation
The spinal cord
① ascending tracts:
Tracts
origin
position
Termination
Function
Pain, temperature
Spinothalamic
Tract
Laminae
Ⅰ,Ⅳ~Ⅶ
Lateral and
ant. Funiculus
Dorsal
thalamus
and simple touch
sensation of trunk
and limbs
Posterior.
nucleus thoracicus
spinocerebellar
Anterior.
spinocerebellar
LaminaeⅤ~Ⅶ
Cerebellum
Lateral
Funiculus
Cerebellum
subconscious
proprioception
from lower
part of trunk
And lower limb