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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.
Click image to play or pause video
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
Slide 7.56Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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
Slide 7.57Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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
Slide 7.63Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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.
Click image to play or pause video
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.
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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
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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.
Click image to play or pause video
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(
Superior orbital fissure
Motor to superior obliquus
Ⅵ Nucleus of abducent nerve )GSE(
Superior orbital fissure
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
Slide 7.67Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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