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1 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/1 Chapter 15 Nervous and Hormonal Coordination in Humans Summary Table 1: The concept of coordination (Section 15.1) Process (Fig. 15.2) Significance Receptors or detectors detect stimuli from the internal or external environment Produces appropriate responses through effectors (tissues or organs) or target organs Body activities can be carried out in an orderly way Allows the body to face different circumstances Maintains steady internal conditions for proper functioning of the cells Table 2: Types of coordination (Section 15.1) Nervous system Endocrine system Nervous coordination Hormonal coordination Transmission of nerve impulses along nerve fibres Running between receptors and effectors Hormones secreted by endocrine glands into the blood Hormones are transported to target organs to produce responses Table 3: Human nervous system (Section 15.2; Fig. 15.3) Brain Brain is protected inside the Central nervous skull system (CNS) Spinal cord Spinal cord is protected inside the vertebral column Peripheral nervous system (PNS) Cranial nerves Spinal nerves Nerves arising from the brain Nerves arising from the spinal cord Link receptors and effectors to the central nervous system Table 4: Basic structure of a neurone (basic unit of the nervous system) (Section 15.2; Fig. 15.4) Description Cell body Consists of a mass of cytoplasm containing a nucleus Nerve fibres Cytoplasmic processes arising from the cell body Extend to the receptors, effectors or other neurones A nerve fibre usually ends in branches called dendrites Nerve fibres carry nerve impulses towards the cell body are called dendrons Nerve fibres carry nerve impulses away from the cell body are called axons Cell bodies of most neurones lie inside the CNS Most nerve fibres are surrounded by myelin sheath 1

2 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/2 Table 5: Myelin sheath (Section 15.2) Functions of myelin sheath Insulates the nerve fibre from the surrounding medium Protects the nerve fibre Helps to speed up the rate of transmission of nerve impulses Table 6: Types of nerve fibres (Section 15.2) Sensory nerve fibres Motor nerve fibres Carry impulses from receptors to the CNS Carry impulses from the CNS to the effectors Table 7: Types of neurones (Section 15.2) Sensory neurone (Fig. 15.5(a)) Motor neurone (Fig. 15.5(b)) Interneurone (association neurone) (Fig. 15.5(c)) Has a long dendron and a short axon Endings of dendrons are connected to receptors Cell body lying on a short side branch Has a number of short dendrons and a long axon Axon branches at its end to form many motor end plates Cell body lying inside the CNS Usually found inside the CNS Transmit nerve impulses from a receptor to the CNS Transmit nerve impulses from the CNS to an effector Make connections between sensory and motor neurones Table 8: Nerve (Section 15.2; Fig. 15.6) Characteristics of a nerve A white, tough string coming out from the spinal cord or brain Consists of bundles of nerve fibres wrapped in connective tissue Mostly contains only sensory or motor nerve fibres Table 9: Nerve impulses (Section 15.2) Nature of nerve impulses Transmitted in the form of electrical charges Travel at a high speed Table 10: Transmission of nerve impulses across neurones (Section 15.2; Fig. 15.8) Transmission of nerve impulses across neurones Neurones are not in direct contact with each other There is a narrow synapse at the point of communication between one neurone and another Synapse ensures that nerve impulses travel from one neurone to another in one direction only (from axon of one neurone to dendron of next neurone) Nerve impulses reach the endings of an axon Chemical substances are released by endings of axons into the synapse Substances diffuse across the synapse and reach the dendron of the next neurone 2

3 Table 11: Spinal cord (Section 15.3; Figs and 15.10) Covered by three membranes Bk2 Ch15 Nervous and Hormonal Coordination in Humans/3 Characteristics of a spinal cord Responsible for transmitting nerve impulses between the brain and other parts of the body Each side is attached to one of a pair of spinal nerves An important centre for reflex actions Table 12: The structure of the spinal cord (Section 15.3; Fig. 15.9) Contains cell bodies of neurones Inner H-shaped region (grey matter) At the centre of grey matter is the central canal Filled with cerebrospinal fluid Supplies nutrients and oxygen to neurones of the spinal cord; allows wastes to leave Outer region Contains nerve fibres only (white matter) Table 13: Cerebrospinal fluid (Section 15.5) Functions of Cerebrospinal fluid Acts as a cushion to absorb shock Maintains the shape of the brain Supplies nutrients and oxygen to neurones; allows wastes to leave Table 14: Spinal nerve (Section 15.3; Fig ) Dorsal root Ventral root Contains sensory neurones which transmit nerve impulses into the spinal cord Cell bodies of sensory neurones group together to form a dorsal root ganglion Contains motor neurones which transmit nerve impulses away from the spinal cord Table 15: Reflex actions (Section 15.4) Characteristics of reflex actions Simple and basic type of body responses Inborn, rapid and automatic (involuntary) Same stimulus always causes the same (fixed) response Form the basis of instinctive behaviour Protecting the body from hazardous or unpleasant stimuli 3

4 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/4 Table 16: Examples of reflex actions (Section 15.4) Withdrawal reflex (Fig ) Knee jerk reflex (Fig ) Fast and automatic Coordinated by spinal cord and spinal nerves Fast and automatic Coordinated by spinal cord and spinal nerves Do not involve interneurone The hand touches a sharp/hot object Pain receptors in the skin are stimulated Nerve impulses are generated and travel along sensory nerve fibres towards the spinal cord through the dorsal root Impulses are passed to interneurones Impulses are passed to motor neurones Impulses are transmitted through the ventral root to effectors Muscle fibres contract the hand is removed from the stimulus Tapping on the tendon just below the knee cap Stretch receptors in the leg are stimulated Nerve impulses are generated and travel along sensory nerve fibres towards the spinal cord through the dorsal root Impulses are passed to motor neurones Impulses are transmitted through the ventral root to effectors Muscle fibres contract the leg kicks up Table 17: Reflex arc (Section 15.4; Fig ) Component of a reflex arc Receptor Sensory neurone Interneurone (maybe absent in some reflex actions) Motor neurone Effector Table 18: Spinal and cranial reflexes (Section 15.4) Spinal reflexes Cranial reflexes Occurring in regions below the head Involve the spinal cord and spinal nerves only e.g. withdrawal reflex and the knee jerk reflex Occurring in the head Involve the brain and cranial nerves only e.g. saliva secretion, pupil constriction Table 19: Main parts of the human brain (Section 15.5; Figs and 15.20) Human brain mainly consists of Cerebrum Cerebellum Medulla 4

5 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/5 Table 20: Cerebrum (Section 15.5; Fig ) Largest part of the brain Characteristics of cerebrum The wall of the cerebrum is highly folded Divided into two halves (right and left cerebral hemispheres) Responsible for voluntary actions Cerebral hemisphere Outer layer (cerebral cortex) is made up of grey matter Inner layer is made up of white matter A large number of neurones can be packed Contains cell bodies of interneurones Contains nerve fibres Table 21: Different areas in the cerebral cortex (Section 15.5; Fig ) Sensory areas Motor areas Association areas Receive nerve impulses from various receptors Give rise to sensations such as touch, smell and taste Send out nerve impulses to motor neurones Control effectors to produce responses Integrate and coordinate incoming sensory information Send nerve impulses to motor areas Controlling intellectual activities Table 22: Cerebellum (Section 15.5; Fig ) Characteristics of cerebellum Highly folded region under the back part of the cerebrum Grey matter lies outside and white mater lies inside Responsible for coordinating muscular movements, maintaining body posture and balance Table 23: Medulla (Section 15.5; Fig ) Characteristics of medulla Lowest part of the brain White matter lies outside and grey matter lies inside An important reflex centre Controls many involuntary body actions Table 24: The differences between reflex and voluntary actions (Section 15.6) Reflex actions Voluntary actions Control of actions Controlled by the medulla or spinal cord Controlled by the cerebrum Nature of actions Not under conscious control (automatic) Under conscious control 5

6 Nature of response No learning is required (inborn) Same stimulus always produces the same response Speed of response Faster Slower Bk2 Ch15 Nervous and Hormonal Coordination in Humans/6 Learning is required Same stimulus may lead to different responses Depending on different situations and previous experiences Table 25: Hormonal coordination in humans (Extension Study) (Section 15.7; Fig ) Characteristics of hormonal coordination Consists of a number of endocrine glands (ductless glands) (Fig.15.24) Secrete hormones that diffuse directly into the blood Examples are pituitary gland, thyroid gland, adrenal glands, pancreas, ovaries and testes Coordination of body activities Table 26: Hormones (Extension Study) (Section 15.7) Important in regulating body activities The nature of hormones Circulated in the blood to all parts of the body Exert their effects in target organs Specific in actions Needed only in small amounts Unused hormones are constantly broken down by the liver and excreted by the kidney Table 27: Maintain a constant blood glucose level by negative feedback mechanism (Extension Study) (Section 15.7; Figs and 15.29) When the blood glucose level is high (e.g. after a meal) Pancreas secrets more insulin Insulin stimulates the liver and skeletal muscle cells to absorb excess glucose from the blood and convert it into glycogen for storage Increases the uptake of glucose by body cells Blood glucose level drops back to normal When the blood glucose level is low (e.g. during fasting or exercise) Pancreas secretes less insulin and more glucagon Body cells take up less glucose from the blood Liver cells break down stored glycogen into glucose and is released into the blood Blood glucose level raises back to normal Table 28: The concept of negative feedback mechanism (Extension Study) (Section 15.7; Fig ) Negative feedback mechanism Increase/decrease in level of a certain factor Detected by a detector Switch on a series of corrective actions The factor is brought back to the normal level (Detector receives feedback continuously about the level of the factor) 6

7 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/7 Table 29: Similarities between nervous and hormonal coordination (Extension Study) (Section 15.7) Similarities between nervous and hormonal coordination Both are important in coordinating body activities Both act by transmitting messages to produce responses Table 30: The differences between nervous and hormonal coordination (Extension Study) (Section 15.7) Components of the system Nature of the message transmitted Methods of transmission Nervous coordination Made up of neurones with nerve fibres running throughout the body In form of electrical charges called nerve impulses Nerve impulses conducted along nerve fibres Rate of transmission Rapid Slow Area affected Restricted to those places supplied with particular nerves, e.g. muscles and glands Duration of response Short Long Nature of responses coordinated Rapid responses such as muscular contractions Hormonal coordination Made up of endocrine glands found in certain regions of the body Chemical substances called hormones Hormones carried in the blood Widespread; one hormone may affect widely separated target organs at the same time Mostly long-term processes such as growth, development and reproduction 7

8 Glossary Bk2 Ch15 Nervous and Hormonal Coordination in Humans/8 coordination 協調 258 the co-working of various body systems to maintain a proper body functioning effector 反應器 258 body structure which responds to stimuli (e.g. muscles and glands) endocrine gland 內分泌腺 258, 276 endocrine system a gland that secrete hormones into the blood rather than into a duct; also called ductless gland 內分泌系統 258 a system in the body, makes up of a collection of glands which produce hormones that control the normal physical and mental development and activities of mammals hormone 激素 188, 258, 277 hormonal coordination nervous coordination 激素協調 258, 276 a chemical produced in small amount by an endocrine gland, carried by the blood and exert its function in target organ; helps to regulate the proper functioning of the body brought about by hormones secreted by endocrine glands of the endocrine system into the blood; hormones are then transported to target organs to produce response 神經協調 258 the maintenance of normal functioning of the body by the transmission of nerve impulses along nerve fibres running between the receptors and effectors, through the central nervous system (the brain or the spinal cord); allows rapid communication among various parts of the body nervous system 神經系統 258 a highly complicated and organized system of neurones which generate electrical signals in form of impulse, so as to coordinates the activities of an animal target organ 目標器官 258 the specific organ on which a hormone will exert its effect 不同的身體系統共同合作, 以維持身體的正常運作 對刺激作出反應的身體構造 ( 如肌肉 腺體 ) 不經管道而直接分泌激素進血液的腺體, 又稱無管腺 體內的一個系統, 由位於不同部位的腺體集合而成, 負責產生激素以控制哺乳動物生理和心理的發展和活動 由內分泌腺少量製造的化學物質, 由血液所帶動, 到達目標器官以發揮其作用, 有助調節體內正常的運作 透過內分泌系統中, 內分泌腺分泌出激素, 隨後運輸至目標器官以產生反應, 以協調身體機能的運作 以神經脈衝的形式, 經中樞神經系統 ( 腦或脊髓 ) 控制, 在感受器與反應器傳遞訊息以維持身體機能正常運作的作用總稱 ; 使身體各部分能夠快速地互相傳送訊息 是動物體內一個高度複雜且有組織的系統, 由神經細胞與腦和脊髓組成, 透過神經傳送神經脈衝以協調動物的活動 會因某激素的作用而產生反應的特定器官 8

9 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/9 brain 腦 259 part of the central nervous system, divided into many parts, such as the cerebrum, the medulla and the cerebellum, each one controlling certain body function central nervous system 中樞神經系統 259 the main information processing system in the body, comprises of the brain and spinal cord in vertebrates cranial nerve 腦神經 259 nerve arising from the brain of vertebrates peripheral nervous system 外周神經系統 skull 顱骨 238, 259, 296 spinal cord 脊髓 259, the nervous system of vertebrates that do not include the brain and spinal chord, and comprises nerves other than cranial nerves and sensory receptors of the body, limbs and internal organs the anterior part of the internal skeleton of the vertebrate, contains and protects the brain a long mass tissue of central nervous system, extends from and connects with the brain and lies within vertebral column 中樞神經系統的一部分, 分成不同部分, 如大腦 延腦和小腦, 每部分負責控制不同的身體功能 身體主要的訊息處理中心, 在脊椎動物中由腦和脊髓構成 由脊椎動物腦部延伸出來的神經 脊椎動物的神經系統, 指除了腦 脊髓及腦神經外, 其他身體四肢和內部器官的感受器和神經 脊椎動物內骨骼的前部分, 包裹及保護腦部 中樞神經系統中呈長形的組織, 由腦延伸出來, 並與它連接, 而其本身則藏於脊柱內 spinal nerve 脊神經 259 nerve from the spinal cord 從脊髓而來的神經 vertebral column 脊柱 152, 259, 296 a series of bones that extend from the head to the tail along the back of the body of vertebrate, enclosing the spinal cord axon 軸突 260 a process of a nerve cell which carries nerve impulses away from the cell body cell body 細胞體 260 the part of nerve cell or neurone containing a nucleus and from which axon and dendrites arise; makes up the grey matter of the spinal cord and brain dendrite 樹狀突 260 a relatively short and highly branched process of a neurone, where impulses are received from other neurones through a synapse dendron 樹突 260 the nerve fibre that carry nerve impulses towards the cell body 從脊椎動物的頭部一直延伸至尾部的一連串骨, 位於背部, 包圍脊髓 神經細胞的延伸, 將神經脈衝帶離細胞體 神經細胞或神經元含細胞核的部分, 樹狀突和軸突自細胞體伸展出來 ; 細胞體構成脊髓和腦的灰質 神經細胞的短而高度分支的幼細延伸物 ; 透過突觸從其他神經細胞接收神經脈衝 將神經脈衝帶到細胞體的神經纖維 9

10 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/10 motor nerve fibre 運動神經纖維 260 fibre of nerve cell that carries nerve impulse away from the central nervous system towards the effector myelin sheath 髓鞘 260 a fatty material covering the axons of neurones in central nervous system of vertebrate; protects the axon and assists in the transmission of nerve impulse nerve fibre 神經纖維 260 the cytoplasmic process of a nerve cell; it may be an axon or a dendron, surrounded with a special membrane, many nerve fibres make up a nerve 把神經脈衝由中樞神經系統帶到反應器的神經細胞纖維 屬脂肪物質, 覆蓋脊椎動物中樞神經系統內的神經元軸突, 以保護軸突, 並協助傳送神經脈衝 神經細胞的細胞質延伸, 可以是軸突或樹突 ; 有特別的膜包圍 ; 多條神經纖維集合成一條神經 neurone 神經元 260 a nerve cell 神經細胞的別稱 sensory nerve fibre association neurone 感覺神經纖維 228, 260 a fibre carrying impulses away from a sensory organ to the spinal cord or brain 聯合神經元 261 an interneurone that makes connections between sensory neurones and motor neurones; usually located inside the central nervous system interneurone 中間神經元 261 make connections between sensory neurones and motor neurones; usually found inside the central nervous system motor end plate 運動終板 261 the end branches of an axon in motor neurones; in contact with muscle fibres motor neurone 運動神經元 261 nerve-cell that conducts nerve impulses from the central nervous system to an effector, such as gland and skeletal muscle sensory neurone 感覺神經元 261 a nerve cell which carries impulses from a receptor to the central nervous system nerve 神經 262 a bundle of axons or dendrites (nerve fibres) which carries impulse to and from the central nervous system synapse 突觸 262 a region where the axon of one neurone joins the dendrite or cell body of another neurone 把神經脈衝從感覺器官帶到脊髓或腦部的神經纖維 屬中間神經元, 負責連接感覺神經元和運動神經元, 通常位於中樞神經系統內 負責連接感覺神經元和運動神經元的神經元, 一般位於中樞神經系統內 為運動神經元的軸突末端分支, 與肌纖維連接 把神經脈衝從中樞神經系統傳遞至反應器的神經細胞, 例子有腺體和骨骼肌 將神經脈衝從感受器帶到中樞神經系統的神經細胞 ( 神經元 ) 多條軸突或樹突 ( 神經纖維 ) 結合成束的構造, 負責將神經脈衝傳送進出中樞神經系統 一個神經元軸突與另一神經元細胞體或樹狀突匯合的區域 10

11 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/11 grey matter 灰質 264 nervous tissue made up of neurone cell bodies, which forms the outer part of the brain and the inner part of the spinal cord white matter 白質 264 the inner part of the brain and the outer part of the spinal cord, consisting of nerve fibres central canal 中央管 265 a canal running through the centre of the spinal cord, containing cerebrospinal fluid cerebrospinal fluid 腦脊髓液 265 fluid found in the brain and spinal cord, supplies the central nervous system with nutrients and oxygen dorsal root 背根 265 the branch of the spinal nerve at the back of animal before entering into the spinal cord dorsal root ganglion 背根節 265 a collection of nerve cell bodies in the dorsal root; containing the nerve cell bodies of the sensory neurons ventral root 腹根 265 the part of the spinal nerve that comes out from the ventral-lateral part of the spinal cord reflex action 反射動作 266 an automatic response which follows a sensory stimulus, the action is not under conscious control and is therefore involuntary, examples include secretions from glands, contraction of cardiac muscle, sweating withdrawal reflex 退縮反射 266 an immediate withdraw of the hand when it touches a sharp object; is a fast and automatic action coordinated by the spinal cord and the spinal nerves reflex arc 反射弧 267 the nervous pathway in a reflex action, consists of a sensory receptor that pass impulses through sensory neurone to the central nervous system, the motor neurone then conduct impulse to an effector to carry out a response 由神經元細胞體構成的神經組織, 形成腦的外層及脊髓內層部分 腦部內層及脊髓外層的部分, 由神經纖維組成 位於脊髓中央的管道, 內含腦脊髓液 在腦和脊髓中的液體, 為中樞神經系統提供氧和營養素 在背部進入脊髓前的脊神經的分支 由背根的神經細胞體集合而成 ; 包含感覺神經元的神經細胞體 從脊髓的前側面位置伸延出來的部分脊神經 受感覺刺激而產生的自動反應, 此反射不受意識控制, 故屬不隨意動作, 例子有腺體的分泌 心肌的收縮 排汗 控制當手接觸尖銳物件時, 迅速抽離的反射作用, 是迅速且自動發生的動作, 由脊髓與脊神經的協調而產生 反射動作中脈衝傳遞的途徑, 當中感受器經感覺神經纖維, 連接往中樞神經系統, 運動神經纖維則把脈衝從中樞神經系統傳送至反應器, 產生反射動作 11

12 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/12 knee jerk reflex 膝躍反射 268 the reflex action taken in the leg when the tendon below the knee cap is tapped; this action does not involve interneurones cranial reflex 腦反射 269 reflex action occurring in the head, involves the brain and cranial nerves spinal reflex 脊髓反射 269 the reflex action occurring in regions below the head, involves the spinal cord and spinal nerves only cranium 顱 270, 296 made up of bones enclosing the brain of vertebrates, fused with the upper jaw association area 聯合區 272 an area of the cerebral cortex where motor and sensory functions are integrated cerebral cortex 大腦皮層 272 the outer, highly convoluted layer of grey matter of the cerebral hemispheres, mainly responsible for higher brain functions, including sensation, voluntary muscle movement, thought, reasoning and memory cerebral hemisphere 大腦半球 272 one of the large paired structures of the cerebrum in vertebrates, the left and right cerebral hemisphere are interconnected cerebrum 大腦 272 the largest part of the brain that controls all voluntary actions motor area 運動區 272 an area in the cerebral cortex that sends out nerve impulses to motor neurones to control the effectors to produce responses sensory area 感覺區 272 a region in the cerebral cortex, receives nerve impulses from various receptors, gives rise to sensations after interpretation voluntary action 隨意動作 272, 275 action that is under the control of will cerebellum 小腦 273 the back portion of the brain in vertebrate which maintain body balance and coordinates muscular activities 指膝蓋靠下的腱受到敲打時, 腿部作出踢起的反射動作, 當中並不牽涉中間神經元 在頭部發生的反射動作, 過程涉及腦和腦神經的參與 在頭以下身體部分發生的反射動作, 僅牽涉及脊髓與脊神經 脊椎動物中包圍腦部的骨, 與上顎合而為一 大腦皮層的一個區域, 負責綜合感應得的訊息和運動功能 大腦半球高度摺疊的外層, 由灰質組成, 主要負責較高層次的腦功能, 例如感覺 隨意動作 思想 記憶和推理等 脊椎動物前腦分成左右兩等分的其中一半, 左右大腦半球是互相連繫的 腦的最大部分 ; 控制所有隨意動作 大腦表層的一個區域, 負責把神經脈衝傳遞至運動神經元, 以控制反應器來作出反應 大腦表層的區域, 從不同的感受器中接收神經脈衝, 經傳譯後產生感覺 受意志控制的動作 脊椎動物腦部的靠後部分, 負責控制身體平衡, 和協調肌肉的運動 12

13 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/13 medulla 延腦 274 portion of the vertebrate hindbrain that contains centres for heart action, respiration, coughing and swallowing conditioned reflex 條件反射 276 automatic reflex action that is acquired by experience or learning ductless gland 無管腺 276 gland which produces secretions and releases them directly into the blood without via any duct, example includes endocrine gland which produces hormones endocrine gland 內分泌腺 258, 276 a gland that secrete hormones into the blood rather than into a duct; also called ductless gland exocrine gland 外分泌腺 276 a gland that discharges its secretion through a duct to the outside of an epithelial membrane, e.g. sweat gland, salivary gland, pancreatic gland hormonal coordination 激素協調 258, 276 brought about by hormones secreted by endocrine glands of the endocrine system into the blood; hormones are then transported to target organs to produce response Ivan Pavlov 巴浦洛夫 276 a Russian physiologist in the 1890s; first studied the nature of conditioned reflex in a scientific way adrenal gland 腎上腺 277, hormone 激素 188, 258, 277 ovary 卵巢 277, a ductless gland situated on top of each kidney in vertebrates, secreting a number of hormones to coordinate various activities a chemical produced in small amount by an endocrine gland, carried by the blood and exert its function in target organ; helps to regulate the proper functioning of the body an organ in female body which produces ova 脊椎動物後腦的一部份, 是心臟活動 呼吸 咳嗽與吞嚥的控制中心 透過經驗或學習而來的自動反射動作 一種腺體, 其製造的分泌物不經管道, 而直接釋進血液中, 例子有分泌激素的內分泌腺 不經管道而直接分泌激素進血液的腺體, 又稱無管腺 把分泌物經導管釋出上皮薄膜以外的腺體, 例子包括汗腺 唾腺和胰腺 透過內分泌系統中, 內分泌腺分泌出激素, 隨後運輸至目標器官以產生反應, 以協調身體機能的運作 1890 年代的俄國生理學家, 是首位以科學方法研究條件反射的性質的科學家 脊椎動物體內各個腎臟上方的內分泌腺, 負責分泌多種激素, 以協調不同的身體活動 由內分泌腺少量製造的化學物質, 由血液所帶動, 到達目標器官以發揮其作用, 有助調節體內正常的運作 在雌性體內製造卵的器官 13

14 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/14 pituitary gland 腦下垂體 277, testis (pl. testes) 睪丸 277, thyroid gland 甲狀腺 277, a ductless gland hanging from the base of the midbrain, secret many hormones which can control body function and also secretions from other endocrine glands such as thyroid gland, adrenal gland and gonad male reproductive organ which produces sperms endocrine gland situated in the neck region of vertebrates which produces the hormone thyroxine, responsible for the control of metabolism insulin 胰島素 278 a hormone secreted by the pancreas, regulates the amount of glucose in blood negative feedback mechanism 負反饋機制 279 an inborn mechanism of the body in which a certain change of the body condition away from normal will automatically lead to a series of reactions to oppose the change, so as to bring the body back to the normal situation glucagon 高血糖素 280 a hormone secreted in the pancreas, stimulates liver cells to break down glycogen into glucose when the blood glucose level falls below the normal level adrenal gland 腎上腺 277, ovary 卵巢 277, pituitary gland 腦下垂體 277, testis (pl. testes) 睪丸 277, a ductless gland situated on top of each kidney in vertebrates, secreting a number of hormones to coordinate various activities an organ in female body which produces ova a ductless gland hanging from the base of the midbrain, secret many hormones which can control body function and also secretions from other endocrine glands such as thyroid gland, adrenal gland and gonad male reproductive organ which produces sperms 從中腦底部伸延出來的無管腺, 可分泌多種激素, 以控制身體功能, 與及其他的內分泌腺的分泌功能, 如甲狀腺 腎上腺和生殖腺等 製造精子的雄性生殖器官 位處脊椎動物頸部的內分泌腺, 產生稱為甲狀腺素的激素, 負責控制代謝作用 從胰臟必泌出來的激素, 負責調節血液內葡萄糖的分量 一個與生俱來的機制, 當身體狀況出現改變, 跟正常出現差別時, 身體會自動作出一系列的反應, 以對抗改變, 使身體狀況回復正常 由胰臟分泌的激素, 能刺激肝細胞在血糖水平低於正常時, 把糖原分解成葡萄糖 脊椎動物體內各個腎臟上方的內分泌腺, 負責分泌多種激素, 以協調不同的身體活動 在雌性體內製造卵的器官 從中腦底部伸延出來的無管腺, 可分泌多種激素, 以控制身體功能, 與及其他的內分泌腺的分泌功能, 如甲狀腺 腎上腺和生殖腺等 製造精子的雄性生殖器官 14

15 Bk2 Ch15 Nervous and Hormonal Coordination in Humans/15 thyroid gland 甲狀腺 277, endocrine gland situated in the neck region of vertebrates which produces the hormone thyroxine, responsible for the control of metabolism 位處脊椎動物頸部的內分泌腺, 產生稱為甲狀腺素的激素, 負責控制代謝作用 15