Nervous System Part 2 for Anatomy

8/13/2019 Nervous System Part 2 for Anatomy

1/167

Spinal Cord, Spinal Nerves and

Autonomic Nervous System


2/167

Spinal Cord


3/167

The spinal cord extends from theforamen magnumto the inferior bordeof the first lumbar vertebra.

Visible features of the spinal cordnclude:


4/167

shallow lonitudinal roove

on the dorsal surface.


5/167

!osteriormedian sulcus


6/167

" deep crease on the ventralsurface.


7/167

Anterior medianfissure


8/167

" alon the lenth ofhe spinal cord the reions devoted

o processin information associatewith the limbs are enlared. Thesenclude:

# " $supplies nerves to the upper limb an!ectoral irdle

# $# " $ " supplies nerves to

he lower limbs and pelvic irdle.


9/167

%nlarement

Cervical %nlarement C&' T(

)umbosacral a*a lumbar%nlarement )+'S


10/167


11/167

The conical end of the spinal

cord.


12/167

Conus medullaris


13/167

slender thread of fibrous piamaterthat extends from the tipof the spinal cord and anchors

onitudinally.


14/167

-ilum terminale


15/167

" The

spinal cord stops rowinbefore the vertebral column. Asa result the dorsal and ventralroots continue to row as their

exit points move further away.

This collection of roots within

the vertebral column at thispoint formthe .


16/167

Cauda %uina


17/167

Spinal Cord Sements


18/167

There are ( spinal cordsements, cervical,thoracic, lumbar, sacral

and coccyeal sements.


19/167

/ cervical,

(+ thoracic,& lumbar,& sacral and

( coccyeal sements.


20/167

%ach sement is associatedwith the pair of spinal nerves

that arise from it.


21/167

The spinal nerves result from thfusion of and

.


22/167

0orsal and Ventral 1oots


23/167

The roots themselves result frothe fusion of thatextend from either side of each

spinal sement


24/167

1ootlets


25/167

The dorsal and ventral roots exthe vertebral column throuh th

.


26/167

2ntervetebral -oramina


27/167

At the exit point there is athat

contains the cell bodies of the

sensory neurons found in thedorsal root.


28/167

0orsal 1oot 3anlion


29/167

The ventral root which contains, fuses with

he dorsal root distalto the

ganglionto form the.


30/167

4otor Neurons

Spinal Nerve


31/167

The arespeciali5ed membranes thatprovide protection, physical

stability and shoc* absorptionwithin the bony vertebral canal


32/167

Spinal menines


33/167

The outer layer consists of

dense irreular connectivetissue.


34/167

0ura 4ater


35/167

6etween the dura materand the inner wall othe vertebral canalthere is an

containin areolarconnective tissue, adipose tissueand bloovessels.


36/167

%pidural Space


37/167

The dura mater is attachedcranially to the athe marin of the

and tapers

distally to form thethat

attaches to the periosteumof

he sacrumand coccyx.


38/167

!eriosteum

-oramen 4anum

Coccyeal )iament


39/167

The is themiddlemenineal layer andconsists of a simple squamous

epitheliumthat attachesdirectly to the inside of thedura mater.


40/167

Arachnoid 4ater


41/167

t is separated by thethat

contains cerebrospinal fluid

(CSF)fromthe .


42/167

Subarachnoid Space

!ia 4ater


43/167

The space between the arachnoand pia mater is also spanned bycollaen and elastic fibers that

orm bundles of fibers called.


44/167

Arachnoid Trabeculae


45/167

The innermost menineal layeconsists of collaen and elasticfibers that adhere closely to the

contours of the nervous tissue.


46/167

!ia mater


47/167

Lateral extensionsof the pia

materand arachnoid materbetween the dorsal and ventrarootsattach to the dura materand are called

.

The preven

side to side and inferiormovement of the spinal cord.


48/167

0enticulate )iaments


49/167

Sectional Anatomy of the SpinaCord


50/167

A narrowruns throuh the center of the

spinal cord.


51/167

Central Canal


52/167

is deepwithin the cord in the shape ofan 7H8 with the cross bar of the

Hlyin over the central canal.


53/167

3rey 4atter


54/167

# $of ray matter that contain

somatic and visceral sensorynuclei.


55/167

posterior #dorsal$ pro9ections


56/167

# $of ray matter that contain the

cell bodies of somatic motorneurons.


57/167

anterior #ventral$ pro9ections


58/167

of ray matter in spinal

segments ! to L"that containvisceral motor neurons.


59/167

)ateral ray horns


60/167

forms the cross bar of the and

contains axons crossin overfrom one side to the other.


61/167

3rey Commissures


62/167

is superficialwith respect to ray matter andis divided into reions by the

posterior and anterior rayhorns.


63/167

;hite 4atter


64/167

The ma9or reions are:


65/167

"between the posterior mediansulcus and posterior ray horns.

"between the anterior medianfissure and the anterior rayhorns.

"between the anterior and

posterior ray horns.


66/167

!osterior white columns

Anterior white columns

)ateral white columns


67/167

;ithin the columns, collectionsof axons performin a similar

function forms a .


68/167

Tract


69/167

Tracts that carry sensoryinformation to the brain are

.


70/167

Ascendin Tracts


71/167

Tracts that carry motornformation to the spinal cord are

.


72/167

0escendin Tracts


73/167

Spinal Nerves


74/167

!eripheral nerves have threelayers of connective tissue:


75/167

is the outermoslayer of connective tissue that iscontinuous with the dura mater.2t also includes the connective

tissue in between any fascicles#bundles$ within the nerve.


76/167

%pineurium


77/167

s the connective tissue sheathhat surrounds a fascicle of

axons.


78/167

!erineurium


79/167

is the delicateconnective tissue fibers that

surround individual axons.


80/167

%ndoneurium


81/167


82/167


83/167

!eripheral 0istribution of SpinaNerves


84/167

After the dorsal and ventralrootsof the spinal sementfusesthe spinal nervedivides

into several branches:


85/167

" is thebranch that innervates the s#in

and muscles of the nec# andbac#.


86/167

0orsal ramus


87/167


88/167

' is thelarer branch that innervates

the ventrolateral body surfaceand the limbs


89/167

Ventral ramus


90/167

the and firsthave

rami communicantesassociated with thenervous system


91/167

thoracic and first two lumbarspinal nerves

autonomic


92/167

The sensory fibers of eachspinal sement collectnformation about a specific

reion of the body surface calleda .


93/167

#sin.ramus communicans$ ' thethoracic and first two lumbarspinal nerves have rami

communicantes #communicatinbranches$ associated with theautonomic nervous system.


94/167

1ami communicantes


95/167


96/167

)oss of sensation in acan be used to dianose

nerve or spinal cord damae.


97/167

dermatome


98/167


99/167


100/167

Nerve !lexuses


101/167

2n the spinal sementscontrollin the skeletal muscle othe neck and the limbs, the

do notremain separate.


102/167

Ventral 1ami


103/167

2nstead, the fibers ofneihborin ventral ramifuseand divide to form interwoven

networ*s of nerves called.


104/167

Nerve !lexuses


105/167

There are

four nerveplexuses:


106/167

forms

rom the ventral ramiof spinalnerves C! $ C%and someibersfrom C&.

Thennervates the diaphram andarises from this plexus.


107/167

Cervical plexus

!hrenic Nerve


108/167

is a

are and complex plexus thatnnervates the pectoral girdleand upper limbwithcontributions from the ventral

rami of C& to !.


109/167

6rachial !lexus


110/167

The nerves that arise from thebrachial plexus include the

, ,

and nerves


111/167

axillary, musculocutaneous,median, ulnar and radial nerve


112/167

isformed by the ventral rami of

T(+ " )


113/167

)umbar !lexus


114/167

The is ama9or nerve that arises from the

umbar plexus.


115/167

-emoral nerve


116/167

contains fibers from the

ventral rami of L% $ S%.


117/167

Sacral !lexus


118/167

The is ama9or nerve of the sacral

plexus.


119/167

Sciatic Nerve


120/167


121/167

A is an immediatenvoluntary response to a

stimulus that never varies.


122/167

1eflex


123/167

The pathway that impulsesfollow to produce the response

s called the .


124/167

1eflex Arc


125/167

The reflex arc can be divided into thefollowin steps:

Step ( " Activation of a by astimulus.

Step + " 2nformation is carried to the CN

n the form of an impulse that travels aloa # $

Step . The information is processed

within the CNS by .

Step


126/167

1eceptor

Sensory #afferent$ fiber

2nterneurons

%fferent

%ffector oran


127/167


128/167

4onosynaptic reflexes


129/167

The simplest reflex arc involvesonly , a sensorand motor neuron with a

betweenthem.


130/167

Two neurons

Sinle synapse


131/167

The is asimple monosynaptic reflexwhich enables a muscle to

automatically ad9ust tone inresponse to stretching.


132/167

Stretch 1eflex


133/167

The most familiar stretch reflex the # '

.


134/167


135/167

A sharp tap on the patellar

liament activates stretchreceptors in themuscle.

Theuic*ly produces a contraction

in the same muscle that results

in a noticeable *ic*.


136/167

=uadriceps -emoris 4uscle

4onosynaptic reflex arc


137/167


138/167

These reflexes involveinterneurons and can be verycomplicated dependin on the

number of interneurons.


139/167

!olysynaptic reflexes


140/167

The withdrawal reflexfrom apainful stimulus is an example

of a .


141/167

!olysynaptic 1eflex


142/167

The coordinates vitalfunctions associated withcardiovascular, respiratory,

diestive, excretory andreproductive functions that areout of our voluntary control.


143/167

Autonomic Nervous System


144/167

Two neurons, connected inseries, sends out the motorcommand.

The first neuron isand has its cell body within the

central nervous system.

The second neuron in the chains and has its cell

bodies outside of the centralnervous system in a ganglion


145/167

!reanlionic

anlionic


146/167

Subdivisions of the ANS

There are two ma9or subdivisionof the ANS


147/167

This division is called the 7fihtor fliht8 division and preparesthe body for exertion, or stress

by increasin tissue metabolism


148/167

Sympathetic 0ivision


149/167

This division is called the 7restand repose8 system andpromotes activities that

conserves or increases enerysuch as diestion.


150/167

!arasympathetic0ivision


151/167

The sympathetic division is alsocalled thebecause it preanlionic neuronare located in the spinal cord

segments ! to L" in the.


152/167

Thoracolumbar division

)ateral ray horns


153/167


154/167

The preganglionic neuronssynapse with ganglionicneurons in ganglianear the

.

These include:


155/167

Vertebral Column


156/167


157/167

theseanlia lie anterior to thevertebral column and innervate

effectors in the abdominal pelvcavity.


158/167

Collateral anlia


159/167


160/167

the corof the adrenal glandrepresents

a modified sympathetic anlion


161/167

Adrenal 4edulla


162/167


163/167

This division is also called thecraniosacral division becauspreanlionic neurons are

ocated in the brainstem and inthe spinal cord sements S+ "S


164/167

!arasympathetic 0ivision


165/167

The preanlionic neurons of thare associated wit

cranial nerves , ,and .


166/167

6rainstem

222, V22, 2> and >.


167/167

Nervous System Part 2 for Anatomy

Documents

Transcript of Nervous System Part 2 for Anatomy