Transcript Chapter 9-中樞神經系統檔案

Chapter 9
The Nervous System: Central
nervous System
1.
General anatomy of the central nervous system ㄧ般解剖構造
2.
The spinal cord 脊髓
3.
The brain 腦
4.
Integrated CNS function: Reflexes 中樞功能的整合：反射
5.
Integrated CNS function: Voluntary motor control 隨意運動調控
6.
Integrated CNS function: Language 語言
7.
Integrated CNS function: Sleep 睡眠
8.
Integrated CNS function: Emotion and motivation 情緒及動機
9.
Integrated CNS function: Learning and memory 學習及記憶
I. General Anatomy of the Central
Nervous System
Glial cells
 90% of CNS composed of glia
 Five types of glial cells
 Astrocytes 星狀細胞-- numerous functions 許多功能
 Ependymal cells室 管膜細胞-- line cavities 形成管腔
 Microglia 小神經膠質細胞– phagocytes 吞噬
 Oligodendrocytes 寡樹突膠質細胞-- form myelin 形成髓鞘
 Schwann cells 許旺氏細胞 (located in PNS)-- form myelin
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Glial Cells
中樞神經系統
室管膜細胞
末梢神經系統
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publishing as Benjamin Cummings.
星狀細胞
小神經
膠質細胞
寡樹突
膠質細胞
Figure 9.1 Glial cells in the nervous system.
許旺氏細胞
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Astrocytes
 Development of neural connections 神經之間的聯繫
 Development of blood-brain barrier 血腦障壁
 Possibly modulate synaptic activity 調控突觸的活性
 Remove neurotransmitter from synaptic cleft
從突觸間隙移除神經傳導物質
 Communicate to neurons through chemical messengers
釋放化學傳導物溝通兩個神經
 Maintain normal electrolyte composition of ISF in CNS
維持中樞間質液間正常電解質組成
 Protect neurons against toxic substances and oxidative stress
保護神經對抗有毒物質及氧化性壓力
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Microglia
 Protect CNS from foreign matter through phagocytosis
藉由吞噬作用保護中樞不受外來物攻擊
 Bacteria
 Dead or injured cells
 Protect CNS from oxidative stress
保護中樞不受氧化性壓力(自由基)攻擊
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Glial cells in neurodegenerative diseases
 Multiple sclerosis 多發性硬化症
 is an autoimmune disease 自體免疫疾病, a disease in which the immune system
attacks a part of the body, in this case oligodendrocytes 寡樹突神經膠細胞
 the loss of myelin 髓鞘 in the CNS slows down or stops communication along
certain neural pathways
 Alzheimer’s disease 阿茲海默症；老年性癡呆
 loss of cholinergic neurons 膽鹼性神經 in certain brain areas and replacement of the
lost neurons with scar疤 tissue called plaques 斑
 during the degeneration of cholinergic neurons, astrocytes 星狀細胞 and microglia
小神經膠細胞 become overly active 過度活化
 Parkinson’s disease 帕金森氏病
 is a degenerative disease involving the loss of dopaminergic neurons 多巴胺神經
 glia cells are thought to enhance neural degeneration through the production of
inflammatory agents
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Physical Support of the CNS
 Bone  outer structure
 Cranium 頭蓋骨；頭顱
 Vertebrae 脊椎骨節；脊柱
 Meninges 腦膜  located between the bony structures and the soft
nervous tissues
 Dura mater 硬腦膜
 Arachnoid mater 蜘蛛網膜
 Pia mater 軟腦膜
 Cerebrospinal fluid (CSF) 腦脊髓液
 the cushioning 墊子 presence of CSF within the subarachnoid
蜘蛛網膜下 space provides yet another level of protection
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Physical Support of the CNS
頭蓋骨；頭顱
硬腦膜
蜘蛛腦膜
軟腦膜
腦膜
脊椎骨節；脊柱
脊髓
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Figure 9.1 Glial cells in the nervous system.
(a,b) Sections of CNS protective structures.
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Physical Support of the CNS
竇
No space exists between the
dura and the arachnoid
蜘蛛網膜絨毛
蜘蛛網膜下空腔
後面(背部)
脊髓
The space between the pia and
arachnoid, called the
subarachnoid space, is filled
with cerebrospinal fluid
蜘蛛網膜
硬腦膜
軟腦膜
脊柱
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前面(腹部)
Figure 9.1 Glial cells in the nervous system.
(a,b) Sections of CNS protective structures.
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Cerebrospinal Fluid (CSF)
 CSF is a clear, watery fluid that bathes the CNS  it is similar (but not
identical) in composition to plasma
 CSF completely surrounds the CNS and it fills a number of cavities
located within the brain and spinal cord
 The brain contains four such cavities, called ventricles 腦室, which are
continuous with the central canal 中心管, a long thin cylindrical cavity
that runs the length of the spinal cord
Table 9.1 Compositions of plasma and CSF
 The lining of the ventricles and
central canal is composed of glial
cells called ependymal cells室管
膜細胞, which are a type of
epithelial cell
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Cerebrospinal Fluid (CSF)
 In some ventricles the lining is vascularized 血管化 and forms a tissue called the
choroid plexus 脈絡膜叢, which consists of pia mater 軟腦膜, capillaries 微血管,
and ependymal cells 室管膜細胞 and functions in the synthesis of CSF
 The total volume of CSF is only 125 – 150 mL, but because it is recycled
approximately three times per day, the choroid plexus must produce 400-500
mL/day
 As CSF is produced it circulates through the ventricular system and enter the
subarachnoid space through openings of the fourth ventricle
 The CSF in the subarachnoid space eventually gets reabsorbed into venous
blood through special structures in the arachnoid mater called arachnoid villi
蜘蛛網膜絨毛
 CSF production by choroid plexus & circulates to subarachnoid space
and ventricles; reabsorbed by arachnoid villi
 Functions of CSF  cushions brain大腦的緩衝墊 & maintains stable
interstitial fluid environment
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Ventricular System of the CNS
蜘蛛網膜絨毛
蜘蛛網膜下空腔
第三腦室
脈絡膜叢
竇
腦幹
大腦
側腦室
第三腦室
小腦
腦幹
脊髓
第四腦室
中心管
小腦
第四腦室
脈絡膜叢
中心管
脊髓
硬膜
蜘蛛網膜
軟膜
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Figure 9.3 Ventricular system of the CNS. The brain’s four ventricles—two lateral ventricles,
the third ventricle, and the fourth ventricle—are continuous with the central canal of the spinal
cord. (a) Lateral view. (b) Frontal view. (c) Relationships of the ventricles to other CNS structures.
Note the presence of the choroid plexus within the ventricles.
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Blood Supply to the CNS
 CNS comprises 2% of body weight (3-4 pounds)  receives 15% of
blood supply
 High metabolic rate
 Brain uses 20% of oxygen consumed by body at rest
 Brain uses 50% of glucose consumed by body at rest
 Depends on blood flow for energy
 Depends on aerobic glycolysis 依賴需氧性的糖解作用
 Requires glucose and oxygen 需要葡萄糖及氧氣
 No glycogen stores 沒有肝醣的儲存
 Fatty acids not used for energy 脂肪酸不能作為能量來源
 Ketones used during extreme conditions 在極端的情況下酮體可作為能量來源
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Stroke
中風
 Caused by decreased blood supply
大腦血流供應量減少所造成
 cause deficit in certain functions, such as the ability to
speak or move an arm
造成大腦某些功能缺陷，例如說話或移動手臂的能力缺陷
 occlusion of cerebral blood vessel 腦血管阻塞引起
 hemorrhage from cerebral blood vessel 腦血管出血引起
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Blood-Brain Barrier
 Capillaries 微血管 = Site of exchange between blood and
interstitial fluid 血液與間質液進行物質交換的地方
 一般微血管有孔洞(pore)可讓一些小分子、水溶性的物質自由進出
，例如葡萄糖、胺基酸等；油溶性的物質則由細胞膜被動擴散；大
分子顆粒則是經由transcytosis運送
 Special anatomy of capillaries in CNS limit exchange = bloodbrain barrier 中樞的血腦障壁是一種特殊的微血管構造，可讓特定
物質進行交換，可保護中樞不會受到血液中一些有毒物質的攻擊
 中樞的微血管內皮細胞之間以緊密結合(tight junction)連接在一起
，沒有孔洞(pore)存在，形成所謂的血腦障壁(BBB)，此緊密結合
(tight junction)可能與星狀細胞(astrocyte)的存在有關。
 中樞因具有血惱障壁，油溶性物質可被動擴散運送，小分子、水溶
性的物質則須經由媒介性運送(mediated transport)，大分子顆粒
則不能經由transcytosis運送進入中樞。
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內皮細胞
孔洞
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星狀細胞
間質液
腦脊髓液
內皮細胞
油溶性
溶質
蛋白質
水溶性
溶質
特定的
水溶性溶質
緊密結合
孔洞
典型的微血管
內皮細胞
蛋白質
媒介物
媒介性
運送
油溶性
溶質
大腦的微血管
Figure 9.4 Blood-brain barrier. (a) Typical capillaries (found in most regions of the body).
Whereas exchange of small hydrophilic molecules occurs by simple diffusion between blood and
interstitial fluid through pores, proteins are too large to cross through pores; some proteins are
transported across capillary walls by transcytosis. (b) Brain capillaries. Because endothelial cells in
these capillaries are connected by tight junctions, hydrophilic molecules must be transported across
the wall by mediated transport systems. Proteins cannot cross the blood-brain barrier because
transcytosis does not occur in brain capillaries. Even though astrocytes are found in close
association with brain capillaries, they do not constitute a functional barrier.
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Gray Matter and White Matter
 Gray = cell bodies 細胞本體, dendrites 樹突, axon terminals 軸突末梢
 灰質約佔中樞的40%，是中樞突觸訊息傳遞及神經整合的地方
 White = axons 軸突  白質約佔中樞的60%，是訊息快速傳遞的地方
在大腦，大部分的灰質位
於外層，白質位於內層
有髓鞘的軸突
在脊髓則相反，白質位於
外層，灰質則位於內層
寡樹突神經膠質細胞
Figure 9.5 Makeup and arrangement of gray matter and white matter in the CNS.
(a) Histology of gray matter and white matter. Whereas gray matter consists primarily of
cell bodies and dendrites and is the site of neural integration, white matter consists
primarily of myelinated axons.
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中間矢狀切面
冠狀切面
大腦皮質
白質
聯絡纖維
灰質
聯合纖維 (胼胝體)
基底核
投射纖維
丘腦
Figure 9.5 Makeup and arrangement of gray matter and white matter in the CNS.
(b,c) Midsagittal and coronal sections of the brain, showing association fibers,
commissural fibers, and projection fibers, tracts of white matter that connect different
areas of the CNS..

Projection fibers 投射纖維  cerebral cortex with lower levels of brain or spinal cord

Association fibers 聯絡纖維  connect two areas of cerebral cortex on same side of brain

Commissural fibers 聯合纖維  connect same cortical regions on two sides of brain

Corpus callosum 胼胝體  primary location of commissural fibers
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II. Spinal Cord
 cylindrical nervous tissue
圓柱狀的神經纖維
 surrounded by vertebral column
為脊椎管所環繞
頸脊神經
 31 pairs of spinal nerves branch off
有31對脊神經的分支
脊髓
 8 Cervical 頸脊神經
 12 Thoracic 胸脊神經
胸脊神經
 5 Lumbar 腰脊神經
 5 Sacral 骶脊神經
脊椎
 1 Coccygeal 尾脊神經
Figure 9.6 The spinal cord. (Left) Location
of the spinal cord, as seen in a posterior
view. (Right) Lateral view of the spinal cord,
showing its position within the bony vertebral
column. As shown are the 31 pairs of spinal
nerves, which leave the spinal cord between
adjacent vertebrae.
腰脊神經
馬尾
骶脊神經
尾脊神經
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Dermatomes 皮節
Figure 9.7 Dermatomes. Each
dermatome is a sensory region on
the surface of the body that is
served by the spinal nerve
indicated by the abbreviations.
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
脊髓分成兩個區域：
中央灰質區與白質
灰質區含有細胞本體
與樹突；白質環繞著
中央灰質區並有髓鞘
的軸突，這些軸突形
成上行及下形路徑

傳入神經元與傳出神
經元的軸突構成脊髓
神經和脊髓相連的
86條(43對)周邊神經

周邊神經系統共有43
對神經，分別為12對
顱神經與31對脊神經
大部分神經同時含
有傳入與傳出神經的
軸突

周邊神經系統的傳出
分支可以分成體神經
及自律神經系統體
神經纖維支配骨骼肌
細胞；自律神經纖維
支配各個腺體及臟器
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Figure 9.8 Spinal cord gray matter and spinal nerves.
This cross section of the spinal cord at the lumbar level
reveals the two functional halves of spinal cord gray matter:
dorsal and ventral. Axons of afferent neurons enter the spinal
cord through the dorsal root and terminate in the dorsal horn;
their cell bodies are located in dorsal root ganglia. Because
they contain axons of both afferent and efferent neurons,
spinal nerves are considered mixed nerves.
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Figure 9.9 Cross section of white matter in the spinal cord. Spinal cord
white matter consists of longitudinal tracts that run between the brain and the
spinal cord or between different spinal cord segments. Ascending tracts
transmit information from spinal cord to brain, whereas descending tracts
transmit information from brain to spinal cord. Only selected tracts are
illustrated here.
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Ascending Tracts
Figure 9.10 Pathway of selected
ascending and descending tracts.
(a) The dorsal column and lateral
spinothalamic tracts. Both of these
ascending pathways originate with
sensory receptors in the periphery and
travel up the spinal cord, eventually
communicating sensory information to
the thalamus and then to the cerebral
cortex. The dorsal column pathway
crosses to the contralateral side in the
brainstem (medial lemniscus), whereas
the spinothalamic tract crosses to
contralateral side in the spinal cord
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Benjamin Cummings.
Descending Tracts
Figure 9.10 Pathway of selected
ascending and descending tracts.
(b) The pyramidal tracts. Both
pyramidal tracts originate in the
primary motor cortex. The lateral
pyramidal tract crosses over in the
medullary pyramids, whereas the
anterior pyramidal tract crosses over
in the spinal cord. Both tracts
terminate in the ventral horn of the
spinal cord, where they
communicate to motor neurons
innervating skeletal muscle.
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III. Brain
Subdivisions of the Brain
1. Forebrain 前腦


Cerebral Cortex 大腦皮質
Basal Nuclei 基底核
Diencephalon 間腦


Thalamus 丘腦
Hypothalamus 下視丘
2. Cerebellum 小腦
3. Brainstem 腦幹



腦部分成六個區域：大腦、間腦、
中腦、橋腦、延腦與小腦

大腦由左右半部所構成，再加上
間腦，共同成為前腦

大腦皮質是大腦的外層，可分為
頂葉、額葉、枕葉與顳葉

間腦包括視丘與下視丘

邊緣系統是前腦深部的構造，與
學習及情緒有關

小腦參與控制姿勢、運動與某些
形式的記憶

中腦、橋腦與延腦共同形成腦幹，
其中有網狀構造
Cerebrum 大腦



Midbrain 中腦
Pons 橋腦
Medulla 延腦
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External View of Divisions of the Brain
Figure 9.11 The brain. The brain is composed of three main parts: forebrain,
cerebellum, and brain stem. (a,b) External views of the brain, showing its three
main parts and their relation to the spinal cord.
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Internal View of Divisions of the Brain
Figure 9.11 The brain. (c ) A midsagittal section of the brain, showing the
structures of three main brain parts. Note the corpus callosum, the major fiber
tract connecting the left and right cerebral hemispheres.
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Cerebellum
 Bilaterally symmetrical
 Cortex + nuclei
 Functions
 Motor coordination and balance
 coordination of eye/body movements
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Brainstem
 Connects forebrain and cerebellum to spinal cord
 Midbrain, connects to forebrain
 Pons, connects to cerebellum
 Medulla, connects to spinal cord
 Processing center for 10/12 cranial nerves
 Reticular formation
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Cerebral Cortex
Figure 9.12 Organization of the cerebral cortex. (a) Convolutions of the
cerebral cortex. (b) Layers of the cerebral cortex. The cell bodies are confined
to a single layer, but axons and dendrites extend across layers. The actual
arrangement of the layers depends on the area of cortex examined.
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額葉
頂葉
枕葉
顳葉
Figure 9.13 Lobes of cerebrum. This lateral view of the left cerebrum shows
its four distinct lobes: frontal, parietal, occipital, and temporal. The central
sulcus separates the frontal and parietal lobes; the lateral sulus separates the
temporal lobe from the frontal and parietal lobes.
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Functional Areas of the Cerebrum
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as Benjamin Cummings.
Figure 9.14 Functional areas of the cerebral cortex. Some selected areas of
the cerebral cortex and the specific functions associated with them are
illustrated.
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Figure 9.15 Motor and sensory homunculi. (a) Cross section of the primary
somatosensory cortex, located just posterior to the central sulcus, and the
corresponding somatotopic map of body parts. (b) Cross section of the primary
motor cortex, located just anterior to the central sulcus, and the corresponding
somatotopic map of body parts.
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Brain Lateralization
 Sensory pathways cross
 Right brain perceives left input
 Left brain perceives right input
 Motor pathways cross
 Right brain controls muscles on left
 Left brain controls muscles on right
 Right brain specializations
 Creativity
 Spatial perception
 Left brain specializations
 Logic
 Analytical abilities
 Language
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Subcortical Nuclei
 Functions of basal nuclei
 Inhibit unwanted movements
 Selecting purposeful
movements
 Postural support
Figure 9.16 Subcortical gray matter. A coronal section of the cerebrum at the
level indicated reveals gray matter areas: the basal nuclei (caudate nucleus,
putamen, and globus pallidus), thalamus, hypotalamus, and the amygdala (part
of the limbic system).
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Diencephalon
 Thalamus

integrate sensory & motor info

sensory relay to cortex
 Hypothalamus

Food intake

Thermoregulation

Link between nervous & endocrine systems

Circadian rhythms

Suprachiasmatic nucleus

Pineal gland
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Limbic System
 Functions of
limbic system
 Learning
 Emotions
 Behavior
Figure 9.17 The limbic system. The major structures of the limbic system as
depicted in this three-dimensional view.
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IV. Integrated CNS Functions:
Reflexes
Reflexes: Automatic patterned response to a stimulus
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Reflex Arc
Figure 9.18 Schematic representation of a reflex arc. The five components
of a reflex arc are a sensory receptor that detects a stimulus, an afferent neuron
that transmits information from the receptor to the CNS, an integration center
(which is generally the CNS), an efferent neuron that transmits information from
the integration center to the periphery, and an effector organ, which produces a
response to the thalamus.
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Stretch Reflex
Figure 9.19 The muscle spindle stretch reflex. The knee-jerk reflex, an example of
the monosynaptic muscle spindle stretch reflex, by which a tap on the patellar tendon
causes contraction of the quadriceps muscle. Muscle spindle afferent neurons make two
synaptic communications in the spinal cord:  excitatory synapse with efferent neurons
to the quadriceps muscle, and  synapses with inhibitory interneurons that
communicate with efferent neurons to the hamstring muscles in the same leg. The
afferent neurons also have collaterals that travel in the white matter of the spinal cord to
the brainstem, where they form synapses with interneurons that transmit information
about muscle length to various area of the brain .
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Withdrawal & CrossedExtensor Reflexes
Figure 9.20 Withdrawal and crossextensor reflexes. In responses to the
activation of a nociceptors, an afferent neuron
synapses on an excitatory interneuron  and
an inhibitory interneuron , ultimately
producing contraction of the hamstrings and
relaxation of the quadriceps in the affected
leg, and affecting in withdrawal.
Simultaneously, the afferent neuron also
synapses with an excitatory interneuron 
and an inhibitory neuron , which ultimately
produces concentration of the quadriceps
and relaxation of the hamstrings in the other
leg. The afferent neuron also synapses with
an interneuron  that crosses to the opposite
side of the spinal cord and travels to the
thalamus to convey information about the
painful stimulus to the brain.
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Pupillary Light Reflex
 Cranial reflex
 Autonomic reflex
 Innate reflex
 Polysynaptic reflex
 Reflex arc: Photoreceptors  Afferent neurons 
Midbrain nuclei  Efferent neurons  Pupils
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V. Integrated CNS Function:
Voluntary Motor Control
Figure 9.21 Steps in voluntary movement. Voluntary movement requires
coordinated activity of several neural structures to ensure smooth skeletal
muscle movement. The process begins with the idea to move.
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Innervation of Skeletal Muscle
 One motor neuron to skeletal muscle cell
 Also called lower motor neuron
 Always excitatory
 To contract muscle cell
 Activate motor neuron
 To relax muscle cell
 Do not activate motor neuron
Input to Motor Neurons
 Afferents (as in reflexes)
 Pyramidal tract neurons
 Extrapyramidal tract neurons
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Pyramidal Tracts
 Fine control of voluntary movement
of the distal extremities
 Upper motor neurons
 Originate in primary motor cortex
 Direct input to motor neurons (some
through interneurons)
 Most cross to contralateral side in
medullary pyramids
Figure 9.22 Pyramidal and
extrapyramidal tracts. (a) Pyramidal
tract. The lateral pyramidal tract is
primarily a crossed pathway, whereas the
anterior pyramidal tract is primarily
uncrossed until it reaches the spinal cord.
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Extrapyramidal Tracts
 All motor pathways outside
pyramidal tracts
 Supportive voluntary movement
of the proximal extremities
 Indirect input to motor neurons
 Several pathways
Figure 9.22 Pyramidal and
extrapyramidal tracts.
(b) Extrapyramidal tracts. These tracts
include all motor tracts except the
pyramidal tracts; some cross, some
do not, and some are bilateral.
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Control of Posture
 Brainstem exerts involuntary control over posture
(extrapyramidal tracts)
 Reticular formation
 Vestibular nuclei
 Red nuclei
 Input to brainstem from
 skin receptors
 eyes
 ears
 proprioceptors
 vestibular apparatus
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The Role of the Cerebellum in Motor
Coordination
 Feedback control of
motor function
 Contributes to muscle
tone
 Stores programs for
remembered activities
Figure 9.23 Major pathways for information flow to and from the
cerebellum. The cerebellum receives information about the status of
movement from sensory areas of the cortex, the brainstem, and the spinal cord.
The cerebellum then transmits information to the cortex via the thalamus,
enabling the cortex to alter its output to modify the movement (as needed) to
accomplish the task smoothly.
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Basal Nuclei in Motor Control
 The basal nuclei are thought to have functions similar to the
cerebellum in that they provide feedback to the cortex for the
development of motor strategies and smoothing out movements
 Some evidence also suggests that the basal nuclei are
necessary for automatic performance of learned repetitive
motions
 The basal nuclei receive input from the cortex and send output
back to the cortex via relay in the thalamus
 One of the functions of this “loop” is to assist the cortex in the
selection and initiation of purposeful movement while inhibiting
unwanted movements
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Huntington’s Chorea
 Genetic disorder of basal nuclei  pathway from basal nuclei
to thalamus lost
 Symptoms
 Loss of motor coordination
 Increased involuntary motions—twitches; jerking motions
 Advanced stages- loss of cognitive functions
Parkinson’s Disease
 Disease of basal nuclei  lack of dopamine in substantia nigra
 Symptoms
 Rigidity- slow stiff movements
 Involuntary movements or tremors
 Stooped, shuffling gait
 Difficulty initiating/stopping movements
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VI. Integrated CNS Functions:
Language
Wernicke’s
Area
Two Language Areas
 Wernicke’s Area
 Language comprehension
 Wernicke’s aphasia
 Broca’s Area
 Language expression
 Broca’s aphasia
Broca’s Area
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VII. Integrated CNS Function:
Sleep
 Active process
 Theories on purpose of sleep
 Lets body rest
 Lets brain rest
 Enhances memory
 Enhances learning
 Mechanisms poorly understood
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Slow Wave and REM Sleep
 There are two phases of sleep whose names depend on whether or not the
eyes move behind the closed eyelids: NREM (non-rapid eye movement)
非快速動眼期 and REM (rapid eye movement) 快速動眼期 sleep
 The EEG waves during NREM sleep are of high amplitude and slow
frequency, so NREM sleep is also referred to as slow-wave sleep
慢波睡眠
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Ascending Reticular Activating System
 Forebrain induces slow wave
sleep
 adenosine
 (adenosine release
blocked by caffeine)
 Pons induces REM sleep
 acetylcholine
Figure 9.24 Ascending reticular activating system. The ascending reticular
activating system is aprt of the reticular formation, a diffuse network of neurons
spread throughout the heighlighted area of the brainstem. The arrows indicate
the spread of excitation that “arouses” the cortex.
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EEG Recording During
Wakefulness and Sleep
Figure 9.25 EEG recordings during
wakefulness and sleep. These graphs are
20-second EEG samples recorded from a
21-year-old female subject. Amplitudes of
EEG recordings are given in microvolts
(mV), and frequencies are given in Hertz
(Hz). (a) Waking EEG is characterized by
high-frequency, low-amplitude waves. (b)
During relaxed waking, alpha waves of 812 Hz are present in the EEG. (c) The EEG
during stage 2 sleep is characterized by
high-amplitude K-complex (seen here at 3
and 14 seconds) and sleep spindles (12- to
15-Hz waves seen here at 6, 10, and 12
seconds). (d, e) High-amplitude delta (0.3-3
Hz) waves are present in stage 3 sleep and
occupy the entire 20-second period in the
sample of stage 4 sleep. (f) EEG amplitude
decrease and frequency increases in REM
sleep.
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Slow Wave and REM Sleep

The initial phase of sleep—NREM sleep—is itself divided into four stages,
each successive stage characterized by an EEG pattern with a slower
frequency and higher amplitude than the preceding one
睡眠初期為 非快速動眼期，又可分四期，每一期都比前一期的頻率更低，振幅更高

Sleep begins with the progression from stage 1 to stage 4, which normally
take 30 to 45 min

If uninterrupted 沒有中斷, sleep continues in this cyclical fashion 循環週期,
moving from stages 1, 2, and 3, to 4 then back up from 4 to 3, 2, and 1,
where NREM sleep is punctuated 打斷 by an episode of REM sleep

REM sleep is also called paradoxical sleep 弔詭睡眠 because the sleeper
is difficult to arouse 很難叫醒 despite having an EEG characteristic of the
alert, awake state 但腦電波卻是與警覺、清醒狀態ㄧ樣

Continuous recording of adults show that the average total night’s sleep
comprises 4 or 5 such cycles, each lasting 90 to min
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Stages of Sleep During One Night
Figure 9.26 Stages of sleep. During 8 hours of sleep, a person moves among
the different sleep stages. Initially, the person progresses from stage 1 SWS to
stage 4 SWS, then returns to REM sleep. As the period of sleep continues,
REM sleep becomes longer and more frequent.
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VIII. Integrated CNS Functions:
Emotions & Motivation
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Figure 9.27 The CNS structures. Various structures of the brain are involved
in producing emotions, both the “feeling” and the responses associated with
them. Cortical association areas integrate thoughts, memory, and sensory
information and communicate to the limbic system. The limbic system “creates”
the emotion, but we are not aware of the emotion until it is transmitted back to
the cortex for perception. Meanwhile, the limbic system also communicates the
emotion to the hypothalamus, which is responsible for bodily responses
coupled with emotion, including hormonal changes (for example, adrenaline
release), motor responses (for example, frowning), and autonomic responses
(for example, changes in heart rate).
Motivation and emotion

Those processes 過程 responsible for the goal-directed quality of
behavior 目標導向特質 are the motivations 動機, or “drives” 驅動力
for that behavior

Primary motivated behavior 原始動機行為 is behavior related directly
stable internal environment 與內在環境恆定有關的行為, such as getting
something to drink when you are thirsty 口渴

In many kinds of behavior, however, the relation between the behavior and
the primary goal is indirect  secondary motivated behavior
次級動機行為，例如並沒有口渴時，想喝某種口味的飲料

The concepts of reward 報償性 and punishment 懲罰性 are inseparable
不可分的 from motivation 動機

Rewards are things that organism work for or things that make the
behavior that leads to them occur more often 重複性的行為—in other
words, positive reinforces  punishments are the opposite 相反
資料來源：Vander’s Human Physiology
Chemical mediators

Dopamine is a major neurotransmitter in the pathway that mediates the
brain reward systems and motivation 多巴胺是腦部參予報償及動機的
主要神經傳導物質

For this reason, drugs that increase synaptic activity in the dopamine
pathways increase self-stimulation rates—that is, they provide positive
reinforcement 可增加多巴胺路徑突觸後活性的藥物，即可增加自我刺激的
速率(正向強化作用)

Amphetamines are an example of such a drug, since they increase the
postsynaptic release of dopamine 安非他命即可促進突觸後釋放多巴胺

Conversely, drugs, such as chlorpromazine, an antipsychotic agent
抗精神病用藥 that blocks dopamine receptors and lowers activity in the
catecholamine pathways, are negatively reinforcing 相反地，抗精神病
用藥阻斷多巴胺接受器及降低兒茶酚胺路徑，造成負向的強化作用

The catecholamines are also implicated in the pathways involved in
learning 學習  this is not unexpected 不意外 since rewards and
punishments are believed to constitute incentives 動機 for learning
資料來源：Vander’s Human Physiology
Altered states of consciousness

States of consciousness 意識狀態 may be different from the commonly
experienced  other, more bizarre sensations, such as those occurring
with hypnosis 催眠, mind-altering drugs 改變精神狀態的藥物, and
certain diseases 疾病, are referred to as altered states of
consciousness 意識的改變狀態
Schizophrenia

One of the diseases that induces altered states of consciousness is
schizophrenia 精神分裂症, a disease in which information is not properly
regulated in the brain

The causes of schizophrenia remain unclear 原因不明 recent studies
suggest that disease reflects a developmental disorder 發育性疾病 in
which neurons migrate or mature abnormally during brain formation 在腦部
形成過程中，神經元的移動或成熟不正常
資料來源：Vander’s Human Physiology
Schizophrenia

The abnormality may be due to a genetic predisposition 遺傳因素
or multiple environmental factors 多重的環境因子 such as viral
infections 病毒感染 and malnutrition 營養失調 during fetal life or
early childhood 在胎兒或嬰兒時期

A widely accepted explanation for schizophrenia suggests that certain
dopamine pathways are overactive
多巴胺路徑過度活化與精神分裂症有關

This hypothesis 假說 is supported by the fact that amphetamine-like
drugs 與安非他命相類似的藥, which enhance dopamine signaling,
make the symptoms worse, and by the fact that the most
therapeutically beneficial drugs 治療藥物 used in treating
schizophrenia block dopamine receptors 增加多巴胺訊息的藥物會
惡化精神分裂症，反之，治療精神分裂症的藥物則是阻斷多巴胺接受器
資料來源：Vander’s Human Physiology
The mood disorders:
depressions and bipolar disorders

The term mood 心情；情感 refers to a pervasive 蔓延的 and sustained
持續的 inner emotion that affects a person’s perception of the world
影響個人對環境的知覺

In the healthy people, moods can be normal, elated 興高采烈的, or
depressed 抑鬱的, and people generally feel that they have some
degree of control over their moods 健康的人對於心情有一定程度
的控制能力

The sense of control is lost 失去控制的感覺, in the mood disorders
情感疾病, which include depressive disorders 憂鬱 and bipolar
disorders 雙極性情感疾病(躁鬱症)

Along with schizophrenia, the mood disorders present the major
psychiatric illness 精神疾病 today 精神分裂症及情感性疾病是目前
主要的精神性疾病
資料來源：Vander’s Human Physiology
Depressions and bipolar disorders

Depressive disorders (depression) 憂鬱 is associated with decreased
neuronal activity and metabolism in the anterior part of the limbic system
邊緣系統 and nearby prefrontal cortex 前額葉皮質

These same brain regions show abnormalities 相同的腦部區域不正常,
albeit inconsistent ones 雖然不是同一個地方, in bipolar disorders

The term bipolar disorders 雙極性情感疾病 describes swings 改變
between manna 躁症 and depression 鬱症

Although the major biogenic amine neurotransmitters (NE, dopamine,
and 5-HT) and acetylcholine have all been implicated 都有參與, the
causes of the mood disorders are unknown 原因未明

Current treatment 治療 of the mood disorders emphasizes drugs and
psychotherapy 精神療法
資料來源：Vander’s Human Physiology
Depressions and bipolar disorders

The classical antidepressant drugs 抗憂鬱藥 are of three types:

The tricyclic antidepressant drugs (TCA) 三環抗憂鬱藥 such as Elavil®,
Norpramin®, and Sinequan® interfere with 5-HT and/or NE reuptake by
presynaptic endings 抑制5-HT及NE的再回收

The monoamine oxidase inhibitors (MAOI) 單胺氧化酶抑制劑 interfere with
the enzyme responsible for the breakdown of these same two
neurotransmitters 抑制5-HT及NE的代謝酶

The serotonin-specific reuptake inhibitors (SSRI) 選擇性的血清胺再回收
抑制劑 are the most widely used antidepressant drugs and include Prozac®
(百憂解), Paxil®, Zoloft

In all three classes, the result is an increased concentration of 5-HT and
(except for the SSRI) NE in the extracellular fluid at synapses
除了SSRI只增加5-HT的濃度外，其餘兩類都是增加突觸5-HT及NE的濃度

Since the biochemical effects of antidepressant medications occur
immediately but the beneficial antidepressant effects appear only after
several weeks of treatment, the known biochemical effect must be only
an early step in a complex sequence that leads to a therapeutic effect of
these drugs 服用抗憂鬱藥會立即增加5-HT及NE的量，
但療效確要好幾個星期後才會呈現
資料來源：Vander’s Human Physiology
Depressions and bipolar disorders

A major drug used in treating patients with bipolar disorder is the
chemical element lithium 鋰, sometimes given in combination with
anticonvulsant drugs 解痙攣劑

It is highly specific, normalizing both manic and depressing moods and
slowing down thinking and motor behavior without causing sedation
鋰鹽專一性很高，對躁症及鬱症都可將其正常化，且減慢思考及運動行為，
但不會造成鎮靜作用

Lithium may interfere with the formation of signaling molecules of the
inositol phosphate family, thereby decreasing the postsynaptic neurons’
response to neurotransmitters that utilize this signal transduction
pathway 干擾IP3次級訊息傳導物的生合成，因而降低神經傳導物在突觸後
訊息傳導的過程

Psychotherapy of various kinds can also be helpful in the treatment of
depression  an alternative treatment 取代療法 when drug therapy and
psychotherapy are not effective is electroconvulsive therapy (ECT)
電痙療法
資料來源：Vander’s Human Physiology
Psychoactive substances, dependence,
and tolerance

Psychoactive substances 精神活性物質 are also used as “recreational”
改造 drugs in a deliberate attempt to elevate mood 提升心情 and produce
unusually states of consciousness 不平常的意識狀態 ranging from
meditational states 思考狀態 to hallucinations 幻覺幻聽

Virtually all the psychoactive substances exert their actions either
directly or indirectly by altering neurotransmitter-receptor interactions
改變神經 傳導物與接受器間的交互作用in the biogenic amine—particularly
dopamine—pathways  ex. cocaine

Substance dependence 物質依賴性, the term now preferred to addition
成癮性, has two facets that may occur either together or independently:

a psychological dependence 心理性依賴 that is experienced as a craving
渴望 for a substance and inability 無能力
to stop using the substance at will

a physical dependence 生理性依賴 that requires one to take the substance
to avoid withdrawal 戒斷, which is the spectrum of unpleasant physiological
symptoms that occurs with cessation 停止 of substance use
資料來源：Vander’s Human Physiology
Psychoactive substances, dependence,
and tolerance

Several neuronal systems are involved in substance dependence, but
most psychoactive substances act on the mesolimbic dopamine
pathway

Although the major neurotransmitter implicated in addiction is dopamine,
other neurotransmitters, including GABA,, enkephalin, serotonin, and
glutamate, are also involved

Tolerance 耐受性 to a substance occurs when increasing doses of the
substance are required to achieve effects that initially occurred in
response to a smaller dose 需增加劑量才能產生跟之前小劑量即能產生的
反應

Moreover, tolerance can develop to another substance as a result of
taking the initial substance, a phenomenon called cross-tolerance
交叉耐受性
資料來源：Vander’s Human Physiology
IX. Integrated CNS Function:
Learning & Memory
Learning = acquisition of new information
 Hippocampus important
 Associative Learning  associate 2 stimuli
 Non-Associative Learning  habituation; sensitization
Memory = retention of information, skills, or thoughts
 Procedural Memory = Implicit
 Automatic response not requiring conscious effort
 Learned motor skills & behaviors
 Cerebellum involved
 Declarative Memory = Explicit
 Learned facts, events, & experiences
 Requires conscious effort for recall
 Hippocampus involved
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Short Term and Long Term Memory
 Information first stored as short term memory  lasts
seconds to hours; information lost unless consolidated
 Consolidation from short term memory to long term
memory  mechanism unknown
 Long term memory  lasts years to lifetime
Plasticity in the Nervous System
 Learning & Memory involve plasticity
 development of new synapses
 long term modulation of existing synapses
 recently shown new neurons develop
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Long-Term Potentiation
Figure 9.28 A mechanism of longterm potentiation. Repetitive
stimulation of a synapse increases the
likelihood that synaptic input will
produce an action potential. (a) At low
levels of activity in the presynaptic cell,
glutamate released from that cell binds
to both receptor types, but the
presence of magnesium in the NMDA
receptor prevents calcium influx; the
net effect is a depolarization of the
postsynaptic cell.
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Long-Term Potentiation
Figure 9.28 A mechanism of longterm potentiation. (b) At high levels of
activity in the presynaptic cell,
increased glutamate release allows
more sodium to enter the postsynaptic
cell, producing a greater depolarization
that forces magnesium out of the
NMDA receptor channel. The resulting
increased calcium inflow activates
protein kinases. One protein kinase
acts on the sodium channel, making it
more sensitive to glutamate; a second
protein kinase triggers production of a
paracrine that causes the presynaptic
cell to produce more glutamate. The
net effect of more glutamate acting on
a more sensitive postsynaptic cell is a
prolong depolarization.
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