Nervous Tissue Neurons: specialized nerve cells conduct impulses Cell body, dendrite, axon Interneuron: between motor & sensory neuron in CNS

Nervous Tissue Neurons: specialized nerve cells conduct

impulses Cell body, dendrite, axon

Interneuron: between motor & sensory neuron in CNS

Neurons

The Neuron Neuron

Dendrites:Collects information from other neurons.

Cell Body

Axon:Transmits information to other neurons.

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Cells of the Nervous System

Neurons – structural classes Multipolar Unipolar Bipolar Interneurons

Glial cells – various types, provide a wide variety of supportive functions

Ganglia

Collections of neuron cell bodies outside the CNS

Nervous System

Central nervous system Brain Spinal cord

Peripheral nervous system Cranial nerves Spinal nerves Ganglia Autonomics

Parts of CNS Cerebrum Cerebellum Mid brain Pones Medulla oblongata Spinal cord

Brain

The Meninges

The meninges are layers of tissue that separate the skull and the brain.

Skull

Dura mater

Arachnoid Layer

Pia Mater

Brain

Spinal cord Located safely in spinal canal Length is 45cm, which extends up to first lumber

vertebra 31 pairs of peripheral nerves starts from spinal

cord Functions of spinal cord

To propagate sensory stimuli from organs to the brain

To carry commands from the brain towards the organs

Reflex action

Anatomy of the Spinal Cord

At 31 places along the spinal cord the dorsal and ventral roots come together to form spinal nerves. Spinal nerves contain both sensory and motor fibers, as do most nerves. Spinal nerves are given numbers which indicate the portion of the vertebral column in which they arise. There are 8 cervical (C1-C8), 12 thoracics (T1-T12), 5 lumbar (L1-L5), 5 sacral (S1-S5), and 1 coccygeal nerve. Nerve C1 arises between the cranium and atlas (1st cervical vertebra) and C8 arises between the 7th cervical and 1st thoracic vertebra. All the others arise below the respective vertebra or former vertebra in the case of the sacrum. Since the actual cord ends at the second lumbar vertebra, the later roots arise close together on the cord and travel downward to exit at the appropriate point. These nerve roots are called the cauda equina because of their resemblance to a horses tail.

Spinal Nerves

Anatomy of the Spinal Cord

Spinal Cord

Extends from foramen magnum to second lumbar vertebra

Segmented Cervical Thoracic Lumbar Sacral

Gives rise to 31 pairs of spinal nerves

Not uniform in diameter throughout length

در موجود شيارهاي و شكافنخاعي سطوح

ميشوند ديده سراسري طولي شيارهاي نخاع خارجي سطح در( -مياني قدامي شكاف ( Anterior Median Fissureالف( -مياني خلفي شيار ( Posterior Median Sulcusب( -جانبي قدامي شيارهاي ( Anterolateral sulcusج( -جانبي خلفي شيارهاي Posterolateral Sulcusد باشد نمي سرتاسري كه :شياري(: اي واسطه خلفي Posterior intermediateشيارهاي

Sulcus ) نيمه هر در پشتي نخاع فوقاني نيمه و گردني نخاع درو مياني خلفي شيار دو فاصل حد در شياري صورت به و نخاع

. باشند مي جانبي خلفي شيار

Cross Section of Spinal Cord

Cross Section of Spinal Cord

White matter: Myelinated axons

forming nerve tracts Fissure and sulcus Three columns:

Ventral Dorsal Lateral

Gray matter: Neuron cell cell bodies,

dendrites, axons ‘Horns’:

Posterior (dorsal) Anterior (ventral) Lateral

Commissures: Gray: Central canal White(see later for white matter

pathways)

CNS

PNSsensory motor motor sensory

spinal nerves (31p) cranial nerves (12p)

spinal cord brain

The Organisation of the Nervous System

• Sensory information has to be passed on from the spinal cord to the brain ascending pathways (red)

• Commands from the brain have to be sent out to the PNSdescending pathways (green)

Spinal Cord AnatomySpinal Cord Anatomy

Slide 7.53c

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Central canal filled with cerebrospinal fluid

Figure 7.19

Spinal Cord AnatomySpinal Cord Anatomy

Slide 7.54Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Meninges cover the spinal cord

Nerves leave at the level of each vertebrae Dorsal root

Associated with the dorsal root ganglia – collections of cell bodies outside the central nervous system

Ventral root

Structure of a NerveStructure of a Nerve


Endoneurium surrounds each fiber

Groups of fibers are bound into fascicles by perineurium

Fascicles are bound together by epineurium

Figure 7.20

Classification of NervesClassification of Nerves


Mixed nerves – both sensory and motor fibers

Afferent (sensory) nerves – carry impulses toward the CNS

Efferent (motor) nerves – carry impulses away from the CNS

Spinal NervesSpinal Nerves


There is a pair of spinal nerves at the level of each vertebrae for a total of 31 pairs

Typical Spinal Nerve Roots (rootlets)

Dorsal = afferent = sensory Ventral = efferent = motor

Primary rami Dorsal = both sensory and motor to deep back,

skin overlying Motor to erector spinae, transversospinal muscles Sensory via medial, lateral cutaneous branches

Ventral = both sensory and motor to rest of body

Dorsal root

Ventral root

Afferent nervefiber

Efferent nervefiber

Ventral horn

Dorsal 1° ramus

Spinal nerve

Ventral 1° ramus

Ventral 1° RamiCutaneous Branches Lateral cutaneous branch

Anterior branch Posterior branch

Anterior cutaneous branch Medial branch Lateral branch

Dorsal root ganglion

Dorsal 1° ramus

Ventral 1° ramus

Posterior br.

Anterior br.

Lateral br.

Lateral cutaneous branch

Anterior cutaneous branch

Medial br.

نخاع هاي برجستگي

خلفي قدامي قطر از آن عرضي قطر و نيست كامل استوانه يك نخاعآن كلي قطر از پائين به باال از همچنين است بيشتر . آن شود مي كاسته

شود مي ديده برجسته محل دو نخاع طول درCervical Enlargement )گردني اعصاب : برجستگي اتصال محل كه

و بوده فوقاني هاي اندام به مربوط )نخاعي . باشد هاي C 2تا Tمي مهره محاذات در تقريبا حد C 2تا T 3و در

هاي 3سگمان(Lumbar Enlargement )كمري اعصاب برجستگي اتصال محل كه

. باشد مي و بوده تحتاني هاي اندام به مربوط در T9 - Tنخاعي تقريبا وهاي مهره سگمانهاي L2 -S 12محاذات حد 3در

مهره محاذات از يعني كمري برجستگي از تر پائين پايين 12در به پشتيدر نخاع باالخره و شده كاسته سرعت به نخاع قطر از

. اين شود مي ختم كمري دوم و اول هاي مهره بين ديسك محاذاتانتهائي مخروط نام به را آخري نامند ( قسمت )Conus Terminaleمي

Spinal nerves join together in plexuses.

A plexus is an interconnection of fibers which form new combinations as the "named" or peripheral nerves. There are four voluntary plexuses (there are also some autonomic plexuses): 1. The cervical plexus, 2. The brachial plexus, 3. The lumbar plexus, and the 4. The sacral plexus. Each plexus gives rise to new combinations of fibers as the peripheral nerves.

Plexus

Intermingling of nerve fibers from more than one source

Spinal nerve = of different spinal nerves Cervical Brachial Lumbar Sacral

Autonomic = of different autonomic fibers

Plexuses Cervical Plexus-the phrenic nerve travels through the thorax to innervate the diaphragm.Brachial Plexus- Axillary nerve-innervates the deltoid muscle and shoulder, along with the posterior aspect of the upper arm. Musculocutaneous nerve- innervates anterior skin of upper arm and elbow flexors. ･Radial nerve - innervates dorsal aspect of the arm and extensors of the elbow, wrist, and fingers, abduction of thumb. ･Median nerve - innervates the middle elbow, wrist and finger flexors, adducts the thumb. ･Ulnar nerve - innervates the medial aspect wrist and finger flexors.

Lumbar Plexus-genitofemoral-to the external genitalia ･obturator-to the adductor muscles. femoral-innervates the skin and muscles of upper thigh, including the quadriceps.

Sacral Plexus gluteal nerves (superior and inferior) - superior innervates the gluteus medius and minimus, inferior innervates the gluteus maximus. ･ sciatic nerve - the body's largest nerve, consisting of two major branches, the tibial and common peroneal. Together they innervate most all of leg including the flexors of the knee, part of adductor magnus, muscles for plantar flexion, dorsiflexion, and other movements of the foot and toes.

The Cervical Plexus

Sensory Branches (superficial)•Lesser occipital- C2-skin of scalp post/sup to ear•Great auricular- C2/3-skin ant/inf/over ear•Transverse cervical- C2/3-skin ant neck•Supraclavicular- C3/4-skin over shest /shoulder

Motor Branches (deep)•Ansa cervicalis- C1, 2/3 sup/inf parts: infrahyoid/geniohyoid, geniohyoid•Phrenic- C3/5-diaphram•Segmental branches- C1-5, deep neck, levator scapulae, mid scalenes

Cervical Plexus

The Brachial Plexus•Dorsal scapular- C5-levator scapulae, rhomboids•Long thoracic- C5-C7-serratus anterior•Subclavius- C5/6-subclavius muscle•Musculocutaneous- C5-C7-coricobrachialis, biceps, brachialis•Lateral Pectoral- C5-C7-Pectoralis major•Upper subscapular- C5/6-Subscapularis•Thoracodorsal- C6-C8 latissimus dorsi•Lower subscapular- C5/6 subscapularis and teres major•Axillary- C5/6 deltoid and teres minor•Median- C5-T1 flexors of forearm except carpi ulnaris, skin/muscles lat palm•Radial- Triceps, extensor muscles of arm/forearm, skin •Medial pectoral- C8-T1 pectoralis major and minor•Medial cutaneous arm/forearm- C8-T1-skin of med and post arm/forearm•Ulnar- C8-T1, flex carpi ulnaris, flex dig profundis, hand muscles skin med

C5C6C7

C8T1

Interminglingfibers

Brachial plexus

C6

C5

C8

C7

T1

The Brachial Plexus

The Lumbar Plexus

•Iliohypogastric- L1-anterior lateral abdominal wall, skin inf abdomen•Ilioinguinal- L1-ant lat abdominal wall, skin med thigh, genitalia•Genitofemoral- L1/2-skin ant thigh, genitalia•lateralcutaneous- L2/3-skin over lat/ant/post thigh•Femoral- L2-L4-thigh flexors/entensors skin-med thigh and foot•Obturator L2-L4-leg adductor muscles

The Sacral Plexus

•Superior gluteal- L4/5 and S1, gluteus minimus, medius, tensor fasciae•Inferior gluteal- L5-S2 gluteus maximus•Piriformis- S1/2 piriformis•Quadratus femoris- L4/5 and S1-quadratus femoris•Obturator- L5-S2 Obturator•Perforating cutaneous- S2/3 skin over inf med buttock•Posterior cutaneous- S1-S3 skin over anal region, inf lat buttock, genetialia•Sciatic- L4-S3 tibial and common fibular•Prudendal- S2-S4 perineum, genetalia

Lumbar and Sacral Plexuses

Dorsal root ganglion Ventral root

Dorsal 1° ramus

Ventral 1° ramus

Lateral cutaneousbranch

Anterior cutaneousbranch

Autonomic(sympathetic)ganglion

External Brain Structures

The Meninges

The meninges are layers of tissue that separate the skull and the brain.

Skull

Dura mater

Arachnoid Layer

Pia Mater

Brain

Cerebrum Biggest part of brain, divided into two hemispheres Contra lateral control Outer surface is grey due to cells Internally white due to fibers Surface is folded to increase the area

Functions of cerebrum Intellect, memory, will power, imagination, emotion & other

psychological functions Receive and perceive the stimuli To give command for reaction with the help of past

experience To control over other parts of nervous system

The Cerebrum

The largest portion of the brain is the cerebrum. It consists of two hemispheres that are connected together at the corpus callosum.

The cerebrum is often divided into five lobes that are responsible for different brain functions.

Corpus callosum

The Cerebrum

The cerebrum’s surface—the neocortex—is convoluted into hundreds of folds.

The neocortex is where all the higher brain functions take place.

Neocortex

Lobes of the Cerebrum

Parietal Lobe

Temporal Lobe

Frontal Lobe

Limbic Lobe

Occipital Lobe

ThalamusThalamus means “inner room” in Greek, as it sits deep in the brain at the top of the brainstem.

The thalamus is called the gateway to the cerebral cortex, as nearly all sensory inputs pass through it to the higher levels of the brain.

Hypothalamus

The hypothalamus sits under the thalamus at the top of the brainstem. Although the hypothalamus is small, it controls many critical bodily functions:

• Controls autonomic nervous system

• Center for emotional response and behavior

• Regulates body temperature

• Regulates food intake

• Regulates water balance and thirst

• Controls sleep-wake cycles

• Controls endocrine system

The hypothalamus is shaded blue. The pituitary gland extends from the hypothalamus.

Mid brain Underneath the cerebrum and above pons

Functions of mid brain To control involuntary functions

Cerebellum Situated below and behind the

cerebrum Functions of cerebellum

Controls tone muscles Helps coordination of body

movements Helps balancing the body

Cerebellum

The cerebellum is connected to the brainstem, and is the center for body movement and balance.


The Brainstem

The brainstem is the most primitive part of the brain and controls the basic functions of life: breathing, heart rate, swallowing, reflexes to sight or sound, sweating, blood pressure, sleep, and balance.

The brainstem can be divided into three major sections.

Detailed brainstem anatomy.


Brainstem Components

Front

RearMore Information:MedullaThalamusPons

Brainstem Divisions

Midbrain

Pons

Medulla Oblongata

The Medulla Oblongata

The medulla oblongata merges seamlessly with the spinal cord and creates the base of the brainstem.

The medulla is primarily a control center for vital involuntary reflexes such as swallowing, vomiting, sneezing, coughing, and regulation of cardiovascular and respiratory activity.

The medulla is also the origin of many cranial nerves.

Pons Below mid brain

Functions of pons Control of consciousness Control level of concentration

Medulla oblongata Lowest part of CNS just above the spinal cord

Functions of Medulla oblongata Control of respiration Control of circulation Control of swallowing and vomiting

The Pons

The pons is the rounded brainstem region between the midbrain and the medulla oblongata. In fact, pons means “bridge” in Latin.

The main function of the pons is to connect the cerebellum to the rest of the brain and to modify the respiratory output of the medulla.

The pons is the origin of several cranial nerves.

The Ventricles


The ventricles are a complex series of spaces and tunnels through the center of the brain.

The ventricles secrete cerebrospinal fluid, which suspends the brain in the skull.

The ventricles also provide a route for chemical messengers that are widely distributed through the central nervous system.

Cerebrospinal Fluid

Cerebrospinal fluid is a colorless liquid that bathes the brain and spine.

It is formed within the ventricles of the brain, and it circulates throughout the central nervous system.

Cerebrospinal fluid fills the ventricles and meninges, allowing the brain to “float” within the skull.


The Cranial Nerves

I. Olfactory nerveII. Optic nerveIII. Oculomotor nerveIV. Trochlear nerveV. Trigeminal nerveVI. Abducens nerveVII. Facial nerveVIII. Vestibulocochlear nerveIX. Glossopharyngeal nerveX. Vagus nerveXI. Accessory nerveXII. Hypoglossal nerve

Brain Functions

• Vision• Taste• Cognition• Emotion• Speech• Language• Hearing• Motor Cortex• Sensory Cortex• Autonomic Functions

Vision

The visual cortex resides in the occipital lobe of the brain.

Sensory impulses travel from the eyes via the optic nerve to the visual cortex.

Damage to the visual cortex can result in blindness.

Speech

Broca’s area is where we formulate speech and the area of the brain that sends motor instructions to the motor cortex.

Injury to Broca’s area can cause difficulty in speaking. The individual may know what words he or she wishes to speak, but will be unable to do so.

Broca’s Area

Language

Wernicke’s area is a specialized portion of the parietal lobe that recognizes and understands written and spoken language.

Wernicke’s area surrounds the auditory association area.

Damage to this part of the brain can result in someone hearing speech, but not understanding it. Wernicke’s Area

Auditory Association Area

HearingThere are two auditory areas of the brain:

• The primary auditory area (brown circle) is what detects sounds that are transmitted from the ear. It is located in the sensory cortex.

• The auditory association area (purple circle) is the part of the brain that is used to recognize the sounds as speech, music, or noise.

Cranial Nerves

Olfactory (I) Optic (II) Oculomotor (III) Trochlear (IV) Trigeminal (V) Abducens (VI) Facial (VII)

Vestibulocochlear (VIII) Also known as auditory

Glossopharyngeal (IX) Vagus (X) Accessory (XI)

Also known as spinal accessory

Hypoglossal (XII)

Names of cranial nerves Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve Ⅵ Abducent nerve Ⅶ Facial nerve Ⅷ Vestibulocochlear nerve Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

Classification of cranial nerves Sensory cranial nerves: contain only afferent (sensory) fibers

ⅠOlfactory nerve ⅡOptic nerve Ⅷ Vestibulocochlear nerve

Motor cranial nerves: contain only efferent (motor) fibers Ⅲ Oculomotor nerve Ⅳ Trochlear nerve ⅥAbducent nerve Ⅺ Accessory nerv Ⅻ Hypoglossal nerve

Mixed nerves: contain both sensory and motor fibers--- ⅤTrigeminal nerve, Ⅶ Facial nerve, ⅨGlossopharyngeal nerve ⅩVagus nerve

Sensory cranial nervesN. Location of cell

body and axon categories

Cranial exit

Terminal nuclei

Main action

Ⅰ Olfactory cells )SVA(

Cribrifomforamina

Olfactory bulb

Smell

Ⅱ Ganglion cells )SSA(

Optic canal

Lateral geniculate body

Vision

Ⅷ Vestibular ganglion)SSA(

Internal acoustic meatus

Vestibular nuclei

Equilibrium

Cochlear ganglion )SSA(

Cochlear nuclei

Hearing

Motor cranial nervesN. Nucleus of origin and

axon categoriesCranial exit Main action

Ⅲ Nucleus of oculomotor )GSE(

Superior orbital fissure

Motot to superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris

Accessory nucleus of oculomotor )GVE(

Parasympathetic to sphincter pupillea and ciliary muscl

Ⅳ Nucleus of trochlear nerve )GSE(


Motor to superior obliquus

Ⅵ Nucleus of abducent nerve )GSE(


Motor to lateral rectus

Ⅺ Nucleus of accessory nerve )SVE(

Jugular foramen Motor to sternocleidomastoid and trapezius

Ⅻ Nucleus of hypoglossal nerve) GSE(

Hypoglossal canal Motot to muscles of tongue

Cranial Nerves Olfactory (I)

Sensory (smell)

• Optic (II)– Sensory (sight)

• Oculomotor (III)– Motor (4 of 6 eye muscles)

– Parasympathetic (constriction of pupil, movement of lens)

Cranial Nerves

Trochlear (IV) Motor (1 eye muscle)

• Trigeminal (V)– Sensory (face, nasal cavity, cheeks, lips, skin of mandible)–Motor (muscles of mastication, anterior belly of digastric, mylohyoid)

• Abducens (VI)– Motor (1 eye muscle)

Cranial Nerves Facial (VII)

Sensory (taste) Motor (facial muscles,

posterior belly of digastric)

Parasympathetic (salivary glands, glands of nasal cavity)

• Vestibulocochlear (VIII)– Sensory (hearing and balance)

• Glossopharyngeal (IX)– Sensory (taste, back of mouth, tonsils, middle ear)– Motor (1 muscle of pharynx)– Parasympathetic (salivary gland, glands of tongue)

Cranial Nerves Vagus (X)

Sensory (taste, back of mouth, larynx, thoracic and abdominal organs)

Motor (muscles of larynx, 1 muscle of tongue)

Parasympathetic (thoracic and abdominal organs)

• Accessory (XI)– Motor (sternocleidomastoid, trapezius)

• Hypoglossal (XII)– Motor (tongue and throat muscles)

Points to Remember

Cranial nerves are part of the peripheral nervous system.

Carry sensory or motor information or a combination and function in parasympathetic nervous system.

Cranial nerves I, II and VIII are purely sensory. Cranial nerves III, IV, VI, XI and XII are motor

(although also function for proprioception).

Autonomic nervous system (Involuntary nervous system) It has control over

Digestion Respiration Circulation Hormone secretion Maintenance of body temperature Maintenance of water balance

Peripheral nervous system 12 pairs of cranial nerves from brain (cranial

nerves) 31 pairs of spinal nerves from spinal cord (spinal

nerves)

Autonomic Nervous SystemAutonomic Nervous System


The involuntary branch of the nervous system

Consists of only motor nerves

Divided into two divisions

Sympathetic division

Parasympathetic division

Autonomic Nervous System

Automatic Regulation of viscera Efferent (motor) 2-neuron pathway 2 antagonistic parts

Sympathetic Parasympathetic

Sympathetic Nervous System Also called thoracolumbar system (T1-L2) Preganglionic cell bodies in lateral horn Preganglionic fibers leave spinal cord with

ventral roots Leave spinal nerve via white rami

communicans Postganglionic cell bodies in ganglia

Sympathetic chain (paravertebral) Collateral (prevertebral)

Sympathetics, Continued Once in sympathetic chain, fibers may—

Synapse at that level, re-enter spinal nerve via gray ramus communicans

Go up the chain before (or after) synapse Go down the chain before (or after) synapse Go through without synapse in chain (as

splanchnic nerves)

Splanchnic nerves Postganglionic fibers go to effector organs Preganglionic fibers relatively short;

postganglionic relatively long

Lateral gray column

White ramuscommunicans

Gray ramuscommunicans

Sympathetics - Functions Prepares body for fight or flight Increases: heart rate, blood pressure, blood flow

to skeletal muscles, respiration Decreases: Peristalsis, blood supply to viscera,

glandular secretion Dilates pupils (Note: no sympathetics in

accommodation) Stimulates sweat glands Stimulus generalized, long-lasting

Parasympathetic Nervous System Craniosacral outflow

Cranial nerves III, VII, IX, X Sacral spinal nerves 2, 3, 4

Preganglionic cell bodies in cranial nuclei, sacral spinal cord

Ganglia Special ganglia in head: ciliary, pterygopalatine,

submandibular, otic Intrinsic ganglia on or in organ innervated

Preganglionic fibers long; postganglionic fibers short

Parasympathetics - Functions Preserve the body as a vegetative organ Decreases heart rate Increases peristalsis Constricts pupil Accommodates eye Empties bladder, rectum Stimulates salivary, lacrimal, digestive glands Stimulus discrete, localized, short-lived Note: no parasympathetics to blood vessels, sweat

glands

Reflex action Protective function of the spinal cord

Sensory organ Afferent nerve Sensory cell in posterior horn of spinal cord Connector nerve Motor cell in anterior horn of spinal cord Efferent nerve End organ of reaction

Functional components General somatic afferent fibers )GSA(: transmit exteroceptive an

d proprioceptive impulses from head and face to somatic sensory nuclei

Special somatic afferent fibers )SSA(: transmit sensory impulses from special sense organs of vision, equilibrium and hearing to the brain

General visceral afferent fibers )GVA(: transmit interoceptive impulses from the viscera to the visceral sensory nuclei

Special visceral afferent fibers )SVA(: transmit sensory impulses from special sense organs of smell and taste to the brain

General somatic efferent fibers )GSE(: innervate skeletal muscles of eye and tongue

Special visceral efferent fibers )SVE(: transmit motor impulses from the brain to skeletal muscles derived from brachial (gill) arches of embryo. These include the muscles of mastication, facial expression and swallowing

General visceral efferent fibers )GVE(: transmit motor impulses from the general visceral motor nuclei and relayed in parasympathetic ganglions. The postganglionic fibers supply cardiac muscles ， smooth muscles and glands

Olfactory nerve

Olfactory mucosa )SVA(→ Cribriform foramina → Olfactory bulb

Optic nerveGanglion cell )SSA( → Optic canal → Lateral geniculate body

Vestibulocochlear nerveVestibular ganglion)SSA( ↘ ↗ Vestibular nuclei Internal acoustic meatus Cochlear ganglion )SSA( ↗ ↘ Cochlear nuclei

Oculomotor nerve Components

General somatic efferent fibers (GSE) General visceral efferent fibers (GVE)

Main action － supplies Superior, inferior and medial recti; inferior obliquus; levator palpebrae superi

oris Sphincter pupillea and ciliary muscle

Ciliary ganglion: lies between optic nerve and lateral rectus

Oculomotor nerve

Abducent nerve

Accessory nerve

Hypoglossal nerve

Hypoglossal nerve

Oculamotor paralysis

Abducent nerve injury

Mixed cranial nerves

Trigeminal nerve

Components of fibers SVE fibers: originate from motor nucleus of trige

minal nerve, and supply masticatory muscles GSA fibers: transmit facial sensation to sensory

nuclei of trigeminal nerve, the GSA fibers have their cell bodies in trigeminal ganglion, which lies on the apex of petrous part of temporal bone

Branches Ophthalmic nerv

e ( 1, sensory) lⅤeave the skull through the superior orbital fissure, to enter orbital cavity

Branches Frontal nerve:

Supratrochlear nerve Supraorbital nerve

Lacrimal nerve Nasociliary nerve

Distribution: Sensation from cerebra

l dura mater Visual organ Mucosa of nose Skin above the eye and

back of nose

Maxillary nerve

( 2, sensory)Ⅴ Leave skull through for

amen rotundum Branches

Infraorbital nerve Zygomatic nerve Superior alveolar nerv

e Pterygopalatine nerve

Distribution: Sensation from cerebral

dura mater Maxillary teeth Mucosa of nose and mo

uth Skin between eye and m

outh

Mandibular nerve ( 3, mixeⅤd)

Leave the skull through the foramen ovale to enter the infratemporal fossa

Branches Auriculotemporal nerve Buccal nerve Lingual nerve Inferior alveolar nerve Nerve of masticatory muscles

Distribution: Sensation from cerebral du

ra mater Teeth and gum of lower jaw Mucosa of floor of mouth Anterior 2/3 of tongue Skin of auricular and tempor

al regions and below the mouth

Motor to masticatory muscles, mylohyoid, and anterior belly of digastric

Facial nerve (Ⅶ)Components of fibers SVE fibers originate from nucleus of facial nerve, and supply faci

al muscles

GVE fibers derived from superior salivatory nucleus and relayed i

n pterygopalatine ganglion and submandibular ganglion. The pos

tganglionic fibers supply lacrimal, submandibular and sublingual

glands

SVA fiber from taste buds of anterior two-thirds of tongue which

cell bodies are in the geniculate ganglion of the facial nerve and

end by synapsing with cells of nucleus of solitary tract

GSA fibers from skin of external ear

Course: leaves skull throu

gh internal acoustic mea

tus, facial canal and styl

omastoid foramen, it the

n enters parotid gland w

here it divides into five br

anches which supply faci

al muscles

Branches within the facial canal Chorda tympani : joins lingual branch of mandibular nerve

To taste buds on anterior two-thirds of tongue

Relayed in submandibular ganglion, the postganglionic fibers supply subman

dibular and sublingual glands

Greater petrosal nerve: GVE fibers pass to pterygopalatine ganglion

and there relayed through the zygomatic and lacrimal nerves to lacrimal

gland

Stapedial nerve : to stapedius

Branches outside of facial canal Temporal Zygomatic Buccal Marginal mandibular Cervical

Pterygopalatine ganglion : lies in pterygopalatine fossa under maxillary nerve

Submandibular ganglion : lies between lingual nerve and submandibular gland

Injury to the facial nerve

Glossopharyngeal nerve (Ⅸ)Components of fibers SVE fibers: originate from nucleus ambiguus, and supply styl

opharygeus GVE fibers: arise from inferior salivatory nucleus and ralyed i

n otic ganglion, the postganglionic fibers supply parotid gland SVA fibers: arise from the cells of inferior ganglion, the centr

al processes of these cells terminate in nucleus of solitary tract, the peripheral processes supply the taste buds on posterior third of tongue

GVA fibers: visceral sensation from mucosa of posterior third of tongue, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, and end by synapsing with cells of nucleus of solitary tract

GSA fibers: sensation from skin of posterior surface of auricle and

Course: leaves the skull via jugular foramen

Branches Lingual branches : to taste buds and mucosa of posteri

or third of tongue Pharyngeal branches : take part in forming the pharynge

al plexus Tympanic nerve : GVE fibers via tympanic and lesser pet

rosal nerves to otic ganglion, with postganglionic fibers via auriculotemporal ( 3) to parotid glandⅤ

Carotid sinus branch : innervations to both carotid sinus and glomus

Others: tonsillar and stylophayngeal branches

Otic ganglion : situated just below foramen ovale

Vagus nerve (Ⅹ)components of fibers GVE fibers: originate from dorsal nucleus of vagu

s nerve, synapse in parasympathetic ganglion, short postganglionic fibers innervate cardiac muscles, smooth muscles and glands of viscera

SVE fibers: originate from ambiguus, to muscles of pharynx and larynx

GVA fibers: carry impulse from viscera in neck, thoracic and abdominal cavity to nucleus of solitary tract

GSA fiber: sensation from auricle, external acoustic meatus and cerebral dura mater

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Nervous Tissue Neurons: specialized nerve cells conduct impulses Cell body, dendrite, axon Interneuron: between motor & sensory neuron in CNS