1. STRUKTUR & FUNGSI
SISTEM SARAF PUSAT
RASHIDDY WONG ABDULLAH
PSUK UNIT PP BPL KKM

3. Copyright 2010, John Wiley & Sons, Inc.
SISTEM SARAF
 Kawalan tubuh dan jaringan komunikasi adalah
berpusat di sistem saraf.Tiga fungsi utama sistem
saraf adalah untuk deria (sensori), integrasi dan
motor.
 Deria (sensori) bertugas untuk mengesan perubahan
di dalam tubuh dan persekitaran luar.
 Integrasi pula bertindak untuk mentafsir perubahan.
 motor memberi respon kepada tafsiran di dalam
bentuk kontraksi otot atau rembesan kelenjar.

4. Copyright 2010, John Wiley & Sons, Inc.
Struktur dan Fungsi Sistem Saraf
 sistem saraf dibahagi kepada dua bhg. Utama.
 sistem saraf pusat
 Sistem saraf periferi
 Organisasi sistem saraf sangat kompleks
 Mempunyai 2 jenis sel
- sel neuron dan neuroglia

6. Neuron terbahagi kepada tiga bahagian:
- badan sel
- dendrit
- akson.
# Badan sel - mengandungi nukleus dan
neukloleus yang dikelilingi oleh sitoplasma.
- berfungsi melakukan proses sintesis bahan-
bahan yang diperlukan oleh sel saraf.

7. Dendrit
# terbina daripada sitoplasma
badan sel yang memanjang dan
kelihatan bercabang-cabang.
- Dendrit bertugas untuk
menghantar impuls ke badan sel.

8. Copyright 2010, John Wiley & Sons, Inc.
Akson
 satu cuaran yang panjang, nipis&mengkhusus.
Akson bertindak sebagai pembawa impuls dari
badan sel keneuron atau tisu lain.
 Akson mempunyai panjang yang berbeza
mengikut tempatia berada.
 Terdapat akson yang diseliputi oleh mielin.
 Sarung mielin berfungsi untuk meningkatkan
kelajuan perjalanan impuls

11. Copyright 2010, John Wiley & Sons, Inc.
Spinal
Meninges
and Spaces

12. Copyright 2010, John Wiley & Sons, Inc.
 Sejenis bahan kimia yang dikenali sebagai
neurotransmiter terhasil di hujung saraf apabila
neuron menerima rangsangan fizikal atau kimia.
 Reseptor akanmenerima neurotransmiter yang
menyebabkan berlaku perubahan elektrik dan
mencetuskan potensial aksi.

13. Sistem Saraf Pusat
 Pusat kawalan seluruh sistem.
 Terdiri daripada otak dan korda spina.
 Sistem saraf pusat menerima semua kederiaan
tubuh melalui reseptor.
 ditafsir untuk menentukan tindakan yang
perlu diambil.
 Rangsangan otot untuk berkontraksi
 kelenjar untuk merembes .

15. Organisasi Sistem Saraf
 Organisasi sistem saraf terbahagi kepada
tiga iaitu otak, korda spina dan saraf.

17. Otak
 Otak organ yang paling penting di dalam
tubuh manusia.
 Otak dianggarkan mempunyai berat kira-kira
1.5kg bagi orang dewasa.
 Otak terletak di dalam rongga kranium dan
merupakan sebahagian sistem saraf pusat.
 Tisu saraf otak adalah lembut, berwarna
kelabu dan putih .

19. OTAK
 Otak terbahagi kepada empat bahagian
utama iaitu batang otak (medula oblongata)
 pons dan otak tengah),
 Diensefalon (talamus dan hipotalamus),
 serebrum dan serebelum.

20. (i) Batang Otak
 Dipanggil sebagai batang otak kerana
bentuknya seperti batang.
 Batang otak terletak di bahagian bawah
kranium.

21. Medula Oblongata
 Berhubung dengan korda spina.
 Mempunyai panjang kira-kira 3cm dan
dipisahkan dari pons oleh alur horizontal.
 Terbina daripada jirim putih
 Pada bahagian posterior bawahnya terdapat
dua nukleus di setiap sisi yang dikenali
sebagai nukleus grasilis dan kuneatus.

22. Pons
 Terletak di atas medula.
 Pons mengandungi jirim putih dan nukleus.
 Nukleus saraf kranial ke 5 hingga ke 8 dan
nukleus pernafasan berada di pons.

23. Otak Tengah
 Terletak di atas pons dan di bawah diensefalon.
 Dua unjuran iaitu pedunkel dan serebrum
terdapat di permukaan ventralnya.
 Unjuran ini berhubung dengan serebrum
selepas lencongan ke anterolateral.
 Empat tuberkel bulat iaitu dua di atas dan dua
dibawah terletak pada permukaan
dorsalnya.

25. (ii) Diensefalon
 Antara otak tengah dan serebrum.
 Struktur utamanya- talamus dan hipotalamus.
 Fungsi talamus adalah sebagai stesen pemancar
untuk impuls deria, ke korteks serebrum.
 Talamus -pusat untuk mentafsir impuls deria
seperti sakit, suhu, sentuhan dan tekanan.
 Hipotalamus pula terdiri daripada banyak struktur.
 hipotalamus - di bawah talamus.

26. Hipotalamus
 Hipotalamus - mengawal suhu tubuh dan
aktiviti autonomik organ-organ bahagian
dalam.
 Selain itu, fungsi yang lain adalah
mencetuskan reaksi emosi seperti
ketakutan dan kemarahan.
 Di hipotalamus juga terdapat pusat
makan, pusat kenyang dan pusat haus.

27. (iii) Serebrum
 Bahagian terbesar otak.
 Ia terbahagi kepada dua hemisfera yang
berwarna kelabu.
 Kedua-dua hemisfera ini dipercayai
 Mengawal aktiviti bagi sebelah tubuh sahaja.
 Deria tubuhsebelah kanan dikawal oleh
hemisfera kiri dan begitulah sebaliknya.

28. Figure 7.19 The motor nerve pathways: upper and lower motor neurones.
Copyright © Elsevier Ltd 2005. All rights reserved.

29.  Fungsi serebrum adalah terlalu banyak dan
kompleks.
 Namun secara umum, korteks serebrum
terbahagi kepada tiga DOMAIN.

30. Deria
 Berfungsi untuk menerima kederiaan dari
kulit, otot dan bahagian dalam tubuh.
 Ia juga menerima impuls dari berbagai-bagai
deria seperti deria rasa, lihat, hidu, dengar
dan sentuh.

31. PUSAT DERIA

32. Motor
 Berfungsi mengawal atur pergerakan otot,
pertuturan dan sebagainya.

33. Asosiasi
 Menghubungkan kawasan motor dan deria
melalui traktusnya.
 Memainkan peranan penting dalam ingatan,
emosi, taakulan,personaliti dan kecerdikan.

34. (iv) Serebelum
 Ia merupakan bahagian kedua terbesar otak.
 Memainkan peranan dalam pergerakan
separa sedar pada otot rangka.
 Pergerakan separa sedar penting untuk
koordinasi, keseimbangan tubuh dan
penetapan kedudukan tubuh.

35. (b) Korda Spina
 Korda spina mempunyai kepanjangan kira-
kira 45cm bagi orang dewasa.
 Kedudukan korda spina adalah bermula dari
dasar tengkorak turun ke bahagian servikal,
torasik dan seterusnya ke bahagian lumbar
atas.

36. Korda spina
 adalah terdiri daripada segmen-segmen .
 pada setiap segmen terdapat sepasang
ganglion.
 Pasangan ganglion tersebut ialah ganglion
akar dorsal dan ganglion akar ventral.

37. Korda Spina
 Pada akar dorsal terdapat akson neuron
deria.
 Membawa maklumat dari periferi ke korda
spina.
 Akar ventral mengandungi akson neuron
motor visera dan somatik yang mengawal
organ efektor.

38.  Saraf spina pula terbentuk daripada
gabungan ganglion akar deria dan akar
motor.
 Saraf ini dikelaskan sebagai saraf campuran
kerana mempunyai kedua-dua serat aferen
dan eferen.

39. Cranial
Nerves

40. 12 CRANIAL NERVE
I. Olfactory: special sensory—smell
II. Optic: special sensory—vision
III. Oculomotor: motor—control of eye
movements
IV. Trochlear: motor—control of eye
movements
V. Trigeminal: mixed
 General sensory: touch, pain, pressure, hot,
cold in face
 Motor: to muscles used for chewing

41. VI. Abducens: motor—control of eye
movements
VII.Facial: mixed
 Special sensory (taste) from anterior of tongue
 Motor to muscles of facial expression, tear
glands, and some salivary glands
VIII.Vestibulocochlear: special sensory—ear

42. IX. Glossopharyngeal: mixed
 Sensory for posterior of tongue, pharynx, and
palate; blood pressure
 Motor to pharyngeal muscles (swallowing),
salivary gland (parotid
X. Vagus: mixed (the major parasympathetic
nerve)
 Sensory from pharynx, ear, diaphragm,
visceral organs in thoracic and abdominal
cavities
 Motor to palatal and pharyngeal muscles
(swallowing and voice); to viscera in thoracic
and abdominal cavities

43. XI. Accessory: motor to voluntary muscles
including sternocleidomastoid and trapezius
(move head, shoulders)
XII.Hypoglossal: motor to tongue (swallowing
and speech)

44. Cerebrospinal Fluid (CSF)
 Formed in the 4 ventricles of brain
 Lateral (#1 and 2)  3rd  4th ventricle
 Formed in choroid plexuses
 By filtration and secretion of blood plasma
 In specialized capillary networks (covered by
ependymal cells) in walls of ventricles
 Pathway
 Through 4 ventricles  central canal of spinal
cord and within subarachnoid space 
 Reabsorbed through arachnoid villi into blood in
superior sagittal sinus
 Cushions brain and provides nutrients

46. Brain Blood Supply and Blood-Brain
Barrier
 Memerlukan 20% keperluan O2 tubuh.
 4 min lack  kerosakan kekal
 Memerlukan bekalan glukos secara
berterusan
 Dilindungi oleh darah-pelindung otak
 Allows passage of lipid soluble materials: O2,
CO2, alcohol, anesthetic agents
 Mengawal kemasukan bahan2 merbahaya
 Created by tight capillaries and astrocytes

47. TAMAT
SEKIAN TERIMA KASIH

48. Copyright 2010, John Wiley & Sons, Inc.
Gross
Anatomy of
Spinal Cord

49. Internal Structure of Spinal Cord
 Gray matter forms “H” (or “butterfly”)
 Three horns on each side; sites of cell bodies
 Posterior gray horns: contain sensory neurons
 Anterior gray horns: contain somatic motor neurons
 Lateral: contain autonomic motor neurons
 White matter (surrounds gray “H”)
 Consists of white columns
 Posterior, anterior, and lateral columns
 Contain tracts (bundles of axons)
 Sensory tracts: ascending to brain
 Motor tracts: descending from brain

50. Internal Structure of Spinal Cord

51. Spinal Nerves
 31 pairs
 Named according to level of vertebra
 C1-C8, T1-T12, L1-L5, S1-S5, 1 coccygeal
 Emerge from spinal cord through intervertebral
foramina
 Nerves attached to spinal cord by 2 roots
 Dorsal root: made of axons of sensory neurons
 Dorsal root ganglion: swelling containing cell bodies of
sensory neurons
 Ventral root: composed of axons of motor neurons
 Both somatic motor and autonomic motor

52. Spinal Nerve Composition
 Formed by 2 spinal nerve roots
 Are mixed:
 Formed from dorsal root (sensory) and ventral
root (motor) root
 Connective tissue coverings
 Individual axons wrapped in endoneurium
 Axons grouped in fascicles wrapped in
perineurium
 Outer covering = epineurium

53. Spinal Nerve Composition

54. Distribution of Spinal Nerves
 Spinal nerves branch after pass through
intervertebral foramina
 Some join with branches from neighboring
nerves to form plexuses
 Nerve names relate to region innervated
 Spinal nerves T2-T12 do not form plexuses
 Called intercostal nerves
 Supply abdominal muscles, skin of chest and
back, and muscles between ribs.

55. Plexuses
 Cervical plexus
 Supplies posterior head, neck, shoulders, and
diaphragm
 Important nerves: phrenic to diaphragm
 Brachial plexus
 Supplies upper limbs + some neck and shoulder
muscles
 Important nerves: radial, ulnar, axial, median to
arm, forearm, hand

56. Plexuses
 Lumbar plexus
 Supplies abdominal wall, external genitalia, and
part of lower limbs
 Important nerves: femoral (to anterior thigh:
quads)
 Sacral plexus
 Supplies buttocks, perineum, and most of lower
limbs
 Important nerves: gluteal, sciatic (to posterior
thigh and all of leg and foot)

57. Spinal
Cord

58. Spinal Cord Functions
 Pathways for nerve impulses within tracts
 Ascending (sensory). Example: spinothalamic
 Descending (motor). Example: corticospinal
 Reflexes: fast, involuntary sequences of
actions in response to stimuli
 Can be simple (withdrawal) or complex (learned
sequence such as driving car)
 Levels
 Spinal (reflex arc): simple
 Cranial: more complex

59. Reflex Arc
1. Sensory receptor: responds to stimulus
2. Sensory neuron: through dorsal root
ganglion and root  posterior horn
3. Integrating center: single synapse
between sensory and motor neurons
4. Motor neuron: from anterior horn 
ventral root  spinal nerve 
5. Effector: muscle responds

60. Example of Reflex Arc: Patellar
Reflex1. Sensory receptor is stimulated by tap on
patellar tendon
2. Sensory neuron: through dorsal root 
spinal cord
3. Integrating center: single synapse in
spinal cord
4. Motor neuron: through ventral root 
spinal nerve  femoral nerve 
5. Effector: quads contract, extend leg

61. Example of Reflex Arc: Patellar
Reflex

62. Brain: Major Parts
 Brain stem: continuous with spinal cord
 Medulla oblongata, pons, midbrain
 Diencephalon: superior to brain stem
 Thalamus, hypothalamus, and pineal gland
 Cerebrum: largest part and most superior
 Surface covered with gray matter: cortex
 Deep to cortex is cerebral white matter
 Cerebellum: posterior and inferior
 Means “little brain”
 Cranial meninges: dura mater, arachnoid
mater, and pia mater

63. Brain: Major Parts

64. Brain: Major Parts

65. Brain Blood Supply and Blood-Brain
Barrier
 Requires 20% of the body’s O2 supply
 4 min lack  permanent damage
 Requires continuous glucose supply
 Protected by blood-brain barrier
 Allows passage of lipid soluble materials: O2,
CO2, alcohol, anesthetic agents
 But controls entry of most harmful materials
 Created by tight capillaries and astrocytes

66. Cerebrospinal Fluid (CSF)
 Formed in the 4 ventricles of brain
 Lateral (#1 and 2)  3rd  4th ventricle
 Formed in choroid plexuses
 By filtration and secretion of blood plasma
 In specialized capillary networks (covered by ependymal
cells) in walls of ventricles
 Pathway
 Through 4 ventricles  central canal of spinal cord
and within subarachnoid space 
 Reabsorbed through arachnoid villi into blood in
superior sagittal sinus
 Cushions brain and provides nutrients

67. Cerebrospinal
Fluid (CSF)

68. Brain Stem: Medulla Oblongata
 Most inferior part of brainstem
 White matter connects spinal cord and other parts
of brain
 Contains vital nuclei
 Cardiovascular center
 Regulates heart rate, blood pressure
 Medullary rhythmicity area
 Adjusts respiratory rhythm
 Other sensory and reflex motor areas
 Cranial nerves VIII-XII attached here

69. Brain Stem: Pons
 Serves as a “bridge”
 Connects medulla to midbrain and above
 Contains ascending and descending tracts
 Connects left and right sides of cerebellum
 Contains nuclei
 Motor relays from cerebrum to cerebellum
 Helps control breathing
 Cranial nerves V-VIII attached here

70. Brain
Stem

71. Brain Stem: Midbrain
 Connects pons to diencephalon
 Large tracts: cerebral peduncles
 Nuclei:
 Substantia nigra: related to Parkinson disease
 Red nuclei: help coordinate movements
 Origin of cranial nerves III and IV (control eye
movements)
 Superior colliculi: nuclei involved in
 Scanning eye movements
 Responses to visual stimuli
 Inferior colliculi: responses to auditory input

72. Reticular Formation
 Netlike arrangement of gray and white matter
 Contains ascending and descending tracts
 Ascending part = reticular activating system
(RAS)
 Carries sensory pathways to cerebral cortex
 Helps maintain consciousness
 Helps induce sleep

73. Reticular Formation

74. Diencephalon
 Thalamus: major sensory relay center
 Also motor, autonomic, and consciousness
functions
 Hypothalamus: lies inferior to thalamus
 Control of pituitary and hormone production
 Works with ANS regulating many viscera
 Involved with feelings and behavior patterns
 Regulation of eating, drinking, fluid levels
 Control of body temperature
 Regulation of circadian rhythms, sleep, waking
 Pineal gland: secretes melatonin
 Controls sleep, biological clock

75. Diencephalon

76. Cerebellum
 Location: posterior to medulla and pons,
inferior to cerebrum
 Attached to brain stem by cerebellar peduncles
 Structure:
 Two cerebellar hemispheres
 Cerebellar cortex: gray matter
 Tree-like appearance (seen in sagittal section) of
white matter and gray nuclei

77. Cerebellum
 Functions
 Receives wide range of sensory input from
muscles, joints, tendons, eyes, inner ears
 Compares actual movements with intended ones
 Helps produce smooth, coordinated movements
 Helps execute skilled motor activities
 Regulates posture and balance

78. Cerebrum: Structure
 Cerebral cortex
 Internal white mater
 Deep gray nuclei
 Surface folds of cerebral cortex: gyri
 Grooves between gyri: sulci
 Longitudinal fissure: divides cerebrum into
left and right hemispheres
 Hemispheres connected by corpus collosum

79. Cerebrum: Structure
 Each hemisphere has 4 lobes
 Frontal, parietal, temporal, occipital
 Central sulcus separates frontal, parietal
 Precentral gyrus anterior to sulcus: primary motor
area
 Postcentral gyrus: primary somatosensory area
 Deep gray nuclei: basal ganglia
 Globus pallidus, putamen, caudate nucleus

80. Cerebrum

81. Cerebrum

82. Limbic System
 Ring of structures on inner border of
cerebrum and floor of diencephalon
 Called “emotional brain”: plays primary role in
pain, pleasure, anger, affection and in
behavior
 Involuntary activity related to survival
 Important in memory development

83. Limbic System

84. Functional Areas of Cerebral Cortex
 Specialized areas in specific regions of
cerebral cortex
 Sensory areas receive input  perception
 Motor areas  initiate movements
 Associative areas  complex integration:
memory, emotion, reasoning, judgment

85. Sensory Areas
 Primary somatosensory area: postcentral
gyrus
 Input includes: touch, proprioception, pain, itching, tickle,
temperature
 Primary visual area: occipital lobe
 Primary auditory area: temporal lobe
 Primary gustatory (taste) area: base of
postcentral gyrus
 Primary olfactory (smell) area: medial
aspect of temporal lobe

86. Motor Areas
 Located anterior to central sulcus
 Primary motor area: precentral gyrus
 Broca’s speech area
 Interacts with premotor area and primary motor
area to regulate breathing and speech muscles
 Is in left hemisphere in 97% of persons

87. Association Areas
 Adjacent to sensory and motor areas and
connected via association tracts
 Integrate and interpret information
 Examples
 Somatosensory association area
 Posterior to primary somatosensory area
 Integrates sensation: exact shape and texture of object
compared with stored memories
 Wernike’s area: left temporal, parietal lobes
 Interprets meaning of speech: words  thoughts
 Right hemisphere adds emotional content

88. Cerebrum: Functional Areas

89. Somatic Sensory Pathways
 Relay sensory information from periphery to
cerebral cortex
 3 neurons in each pathway
 Cell body #1 in dorsal root ganglion
 Cell body #2 in spinal cord or brain stem
 Cell body #3 in thalamus; axon extends to
cerebral cortex (somatosensory area in
postcentral gyrus)
 Most sensory input to right side of body
reaches left side of brain (and vice versa)

90. Somatic Sensory Pathways
 Posterior column - medial lemniscus pathway
senses
 Fine touch: body location, texture, size
 Proprioception: position and motion of body parts
 Vibrations: fluctuating touch stimuli
 Spinothalamic pathways
 Anterior and lateral spinothalamic tracts
 Relay impulses for pain, tickle, itch, hot, and cold
sensations

91. Somatic
Sensory
Pathways

92. Somatic Motor Pathways
 Signals come from
 Upper motor neurons: via corticospinal tracts
 Basal ganglia: help with muscle tone
 Cerebellum: coordination
 Sensory neurons or interneurons via reflexes
 Impulses activate lower motor neurons
 Cell bodies in anterior gray of spinal cord
 Axons  ventral root  spinal nerve  muscle 
voluntary movements

93. Somatic Motor
Pathways

94. Somatic Sensory and Motor Pathways
Interactions Animation
 Somatic Sensory and Motor Pathways
You must be connected to the internet to run this animation.

95. Lateralization
 Brain controls opposite side of the body: all
sensory and motor pathways cross in CNS
 Left side of the brain controls right side of body
 Right side of brain controls left side of body
 Left hemisphere important for spoken and
written language, numerical and scientific
skills, and reasoning
 Right side more involved with spatial and
pattern recognition and emotional content

96. Memory
 Process for storing and retrieving information
 Involves structural and functional changes
 Involves association areas, parts of limbic
system, and diencephalon
 Skill memory also involves cerebellum and
basal ganglia

97. Cranial Nerves (Table 10.2)
I. Olfactory: special sensory—smell
II. Optic: special sensory—vision
III. Oculomotor: motor—control of eye
movements
IV. Trochlear: motor—control of eye movements
V. Trigeminal: mixed
 General sensory: touch, pain, pressure, hot,
cold in face
 Motor: to muscles used for chewing

98. Cranial Nerves
VI. Abducens: motor—control of eye
movements
VII.Facial: mixed
 Special sensory (taste) from anterior of tongue
 Motor to muscles of facial expression, tear
glands, and some salivary glands
VIII.Vestibulocochlear: special sensory—ear

99. Cranial Nerves
IX. Glossopharyngeal: mixed
 Sensory for posterior of tongue, pharynx, and
palate; blood pressure
 Motor to pharyngeal muscles (swallowing),
salivary gland (parotid

100. Cranial Nerves
X. Vagus: mixed (the major parasympathetic
nerve)
 Sensory from pharynx, ear, diaphragm,
visceral organs in thoracic and abdominal
cavities
 Motor to palatal and pharyngeal muscles
(swallowing and voice); to viscera in thoracic
and abdominal cavities

101. Cranial Nerves
XI. Accessory: motor to voluntary muscles
including sternocleidomastoid and trapezius
(move head, shoulders)
XII.Hypoglossal: motor to tongue (swallowing
and speech)

102. Aging
 Rapid brain growth during first few years of
life
 Due to increase in size of neurons and
proliferation of neuroglia
 Increase in development of dendritic branches
and synaptic contacts
 From early adulthood through old age:
 Decline in brain mass
 Fewer synaptic contacts brain function
 Some decrease in brain function