Nervous Nervous systemsystem

SHANDONG UNIVERSITY Liu Zhiyu

一、一、 Divisions of nervous systemDivisions of nervous system

ⅠⅠ) ) Central nervous systemCentral nervous system (CNS)(CNS)

Pons Pons Midbrain Midbrain

Medulla oblongata Medulla oblongata

CerebellumCerebellum

TTelencephalonelencephalon

DiencephalonDiencephalon

Brain stem Brain stem CNSCNS

Spinal cord Spinal cord

BrainBrain

ⅡⅡ)) Peripheral nervous system Peripheral nervous system (PNS)(PNS)

PNSPNS

Visceral motor n.

Visceral sensory n.

Sympathetic part

Parasympathetic part

Cranial n. (12 pairs) Spinal n. (31 pairs)

Somatic sensory n.

Somatic motor n.

Visceral n.

Somatic nerve

I. I. Essential struncturesEssential strunctures

of nervous systemof nervous system

cell bodycell body DendritesDendrites

AxonAxon

glial cellglial cell

Bipolar neuron Pseudounipolar neuron Multipolar neuron

central branch peripheral branch

NeuronsNeurons

Nuroglia:Nuroglia:

Ⅰ) Structural classification

Afferent (sensory) neuronAfferent (sensory) neuron Efferent (motor) neuronEfferent (motor) neuron Association neuron (interneuronAssociation neuron (interneuron))

ⅡⅡ) ) Functional classificationFunctional classification

Nerve fiberNerve fiber myelinated nerve fiber myelinated nerve fiber

unmyelinated nerve fiber unmyelinated nerve fiber

NerveNerve　　

II 、 reflex reflex arc

Reflex: a reaction of the organism by the nervous system in response to a stimulus

Reflex arc: consist of 5 basic components

centre

efferent neuron effector

afferent neuron

receptor

Spinal nervesSpinal nerves                                Formation: each spinal nerve is formed by union of anterior and posterior roots at intervertebral foramen The anterior root contains

motor fibers for skeletal muscles.

The posterior rootcontains sensory fibers whose cell bodies are in the spinal ganglion

Spinal nervesSpinal nerves                                Spinal gangliaSpinal ganglia

is an enlargement of the posterior root near the iis an enlargement of the posterior root near the i

ntervertebral foramen which consist of the bodintervertebral foramen which consist of the bodi

es of pseudounipolar neuronses of pseudounipolar neurons

Divisions of spinal nervesDivisions of spinal nerves

:: cervical nerves 8cervical nerves 8 对对

thoracic nerves 12thoracic nerves 12 对对 lumbar nerves 5lumbar nerves 5 对对 sacral nerves sacral nerves :5:5 对对 coccygeal nerve : 1coccygeal nerve : 1 对对

The fiber components of spinaThe fiber components of spinal corsl cors

Somatic afferent (sensory) nerve fibers Somatic afferent (sensory) nerve fibers : : Visceral afferent (sensory) nerve Visceral afferent (sensory) nerve fibers fibers

There are four types of fibers contained in the spinal n.There are four types of fibers contained in the spinal n.

Somatic efferent (motor) nerve fibersSomatic efferent (motor) nerve fibers ：： Visceral efferent (motorVisceral efferent (motor)) nerve fibers nerve fibers ：：

branches of spinal nervesbranches of spinal nerves

anterior branche anterior branche posterior branche posterior branche

meningeal branchmeningeal branchcommunicating branc communicating branc

Each spinal n. is divided into 4 branches after leaEach spinal n. is divided into 4 branches after leaving the intervertebral foramen immediatelyving the intervertebral foramen immediately

posterior brancheposterior branche

anterior brancheanterior branche ：：，，

cervical plexuscervical plexusbranchial plexus branchial plexus lumbarlumbar plexus plexus sacral plexus sacral plexus 。。

二、二、 cervical plexuscervical plexus

Formation Formation ：： it it consists of the antconsists of the ant

erior rami of C1-C4 erior rami of C1-C4 nerves.nerves.

BranchesBranches ：： Cutaneous branchesCutaneous branches

Muscular brnchesMuscular brnches

Cutaneous branches:

Lesser occipital Great auricular Transverse nerve of neck Supraclavicular nerves

They emerge around middle of posterior border of sternocleidomastoid, to supply skin of neck and scalp between auricle and external occipital protuberance

Branches

Muscular branchesMuscular branches::

supply the deep muscles supply the deep muscles of neckof neck

Phrenic nervePhrenic nerve arisarises from the of C3-C5, es from the of C3-C5,

innervation to diaphragm;innervation to diaphragm;

Phrenic nervePhrenic nerve

Sensory fibersSensory fibers supply supply to pleurae, pericardium to pleurae, pericardium and peritoneum of diapand peritoneum of diaphragm; usually right phrhragm; usually right phrenic nerve may be distrenic nerve may be distributed on live, gallbladdibuted on live, gallbladder and biliary system.er and biliary system.

二、 二、 brachial plexusbrachial plexus

Passes through the scalene fiPasses through the scalene fissure (ssure ( 斜角肌间隙斜角肌间隙 ) to poster) to posterosuperior of subclavian artery, osuperior of subclavian artery, then enters the axilla to form t then enters the axilla to form three cords(hree cords( 束束 ) which around ) which around the axillary atery.the axillary atery.

FormationFormation ：：Formed by anterior rami of C5-C8 and T1 nerves

PositionPosition ：：

Medial cord Medial cord 、、 Lateral cord Lateral cord Posterior cord Posterior cord

二、 二、 brachial plexusbrachial plexus

Median nerve Median nerve

Musculocutaineous nerve Musculocutaineous nerve

Ulnar nerve Ulnar nerve

Axillary nerveAxillary nerve

Radial nerve Radial nerve

BranchesBranches

AAnterior branche of thoracic nerventerior branche of thoracic nerve

Intercostal nervesIntercostal nerves （（ TT1-T-T11），），

，，

DistributionDistribution: : intercostales intercostales anterolateral abdominal anterolateral abdominal musclesmusclesskin of thoracic and abdoskin of thoracic and abdominal wall, parietal pleurminal wall, parietal pleura and peritoneuma and peritoneum

Subcostal nerveSubcostal nerve （（ T2T2 ） ） ，。

Anterior branches of thoracic Anterior branches of thoracic nervesnerves

The distribution of the antThe distribution of the anterior branches of the therior branches of the thoracic n. is segmentaloracic n. is segmental. .

T2 Sternal angle T2 Sternal angle T4 Nipple T4 Nipple T6 Xiphoid processT6 Xiphoid processT8 Costal archT8 Costal archT10 Umbilicus T10 Umbilicus T12T12 Midpoint between uMidpoint between u

mbilicus and symphysmbilicus and symphysis pubis is pubis

四、四、 lumbar plexuslumbar plexus

anterior rami of L1-L3, a part of anterior rami of T12 and L4

Formation:

positionposition ：： lies behind the psoas major and beside the lumbar vertera

branchesbranches ：：Femoral

Obturator

Cutaneous

Genitofemoral

Iliohypogastric

Ilioinguinal

Lateral femoral

routeroute ：： Runs downward and laterRuns downward and later

ally between psoas major ally between psoas major and iliacus, passes deep tand iliacus, passes deep to inguinal ligament;o inguinal ligament;

disributiondisribution muscular branches-muscular branches-----suppsupp

lies anterior thigh muscles lies anterior thigh muscles (quadricep(quadricep 肌肌 ,sartorius an,sartorius and pectineus), d pectineus),

Femoral n. Femoral n.

sensory branches-sensory branches-----

hip and knee joint, and skin hip and knee joint, and skin on anteromedial side of thigon anteromedial side of thigh, h,

saphenous nervesaphenous nerve is distris distributed to skin of medial side ibuted to skin of medial side of leg and footof leg and foot

Femoral n. Femoral n.

RouteRoute ：： Enters thigh through obturEnters thigh through obtur

ator foramen; ator foramen; DistributionDistribution ：： muscular branches-muscular branches----- su su

pplies medial group of mupplies medial group of muscles of thigh, obturator escles of thigh, obturator externus,xternus,

sensory branches-sensory branches----- skin skin of medial side of thigh of medial side of thigh

Obturator Obturator

Lateral femoral cutaneous

It arises from the lateral It arises from the lateral border of the psoas majoborder of the psoas major and runs inferolateral tr and runs inferolateral to enter the thigh posterioo enter the thigh posterior to the inguinal lig.,just r to the inguinal lig.,just medial to the anterior sumedial to the anterior superior iliac spine. it distriperior iliac spine. it distribute to the skin over the bute to the skin over the lateral aspect of the thiglateral aspect of the thigh.h.

Genitofemoral

It pierces the anterior suIt pierces the anterior surface of the psoas major rface of the psoas major and runs inferiorly ,and dand runs inferiorly ,and divide into ivide into femoralfemoral and and ggenitalenital branches branches

The The femoralfemoral branche di branche distribute to the skin over tstribute to the skin over the femoral triangle; and he femoral triangle; and the the genitalgenital branche distr branche distribute to the scrotum(greibute to the scrotum(greater lip of pudendum)ater lip of pudendum)

五、 五、 sacral plexussacral plexus

  formationformation ：：

formed by anterior rami of L4 and L5 spinal nerves (the lumbrosacral trunk) and anterior rami of sacral and coccygeal nerves

Position:

lies in pelvic cavity, anterior to sacrum and piriformis

五、 五、 sacral plexussacral plexus

main branchesbranches Sciatic nerveSciatic nerve

Pudendal nervePudendal nerve Superior gluteal nSuperior gluteal n. .

Inferior glureal n.Inferior glureal n.

Sciatic nerveSciatic nerve Leaves pelvis through infraLeaves pelvis through infra

piriform foramen to enter glpiriform foramen to enter gluteal region,uteal region,

runs inferiorly deep to glutruns inferiorly deep to gluteus maximus, passing mideus maximus, passing midway between the greater troway between the greater trochanter of femur and ischial chanter of femur and ischial tuberosity to back of thigh, tuberosity to back of thigh, lying deep to long head of blying deep to long head of biceps femoris, iceps femoris,

normally divided intonormally divided into tibial tibial and and common peroneal nervcommon peroneal nerveses just above popliteal foss just above popliteal fossa;a;

Sciatic nerve Sciatic nerve it innervates semitendinoit innervates semitendino

sussus

SemimembranosusSemimembranosus

and biceps femorisand biceps femoris

Tibial nerve Tibial nerve

Decends through popliteDecends through popliteal fossa , then runs inferal fossa , then runs inferiorly with posterior tibiaiorly with posterior tibial vessels and dividing inl vessels and dividing into medial and lateral plato medial and lateral plantar nerves behind the mntar nerves behind the medial malleolus; supplieedial malleolus; supplies posterior muscles of les posterior muscles of leg and knee jointg and knee joint

Common peroneal nerve Common peroneal nerve

Arises at apex of popliteal fArises at apex of popliteal fossa and follows medial boossa and follows medial border of biceps femoris and irder of biceps femoris and its tendon; passes over posts tendon; passes over posterior aspect of head of fibuterior aspect of head of fibula and then winds around nla and then winds around neck of fibula, deep to peroneck of fibula, deep to peroneus longus, where it divideeus longus, where it divides into deep and superficial s into deep and superficial peroneal nerves,to supply tperoneal nerves,to supply the anterior and lateral grouhe anterior and lateral groups m. of the leg.ps m. of the leg.

Superficial peroneal

Deep peroneal