Chapter 6

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1 Section C SYNAPSES

2 I. Functional Anatomy of Synapses

3 1. More than one neurotransmitter may be simultaneously released from an axon (cotransmitter). 泌 () 2. A neurotransmitter, which is stored in synaptic vesicles in the presynaptic axon terminal, carries the signal from a pre- to a postsynaptic neuron.

A neurotransmitter, which is stored in synaptic vesicles in

4 粒

6 Mechanisms of Neurotransmitter Release 1. Depolarization of the axon terminal opens the voltage-gated calcium channels and raises the calcium concentration within the terminal, which causes the synaptic vesicles to fuse with the presynaptic plasma membranehe and the release of neurotransmitter into the synaptic cleft. 離離度

raises the calcium concentration within the terminal, which causes the synaptic

7 2. The neurotransmitter diffuses across the synaptic cleft and binds to receptors on the postsynaptic cell. The activated receptors themselves may contain an ion channel, or they may act indirectly, via a G protein, on separate ion channels. 離 G 離

The activated receptors themselves may contain an ion

8 3. Docking of synaptic vesicles is mediated by the interaction of a number of protein, including SNARE protein, which are found on both the vesicle and plasma membranes. SNARE ( )

9 4.The precise mechanism by which an increase in intracellular calcium initiates the process of vesicle fusion is still unclear, and is an active area of research. It may involve a protein called synaptotagmin that associates with SNAREs and bind calcium. 離, 不, synaptotagmin, SNAREs 離

10 2. Ca 離裂

11 Unbound neurotransmitters are removed when they (a) are actively transported back into the axon terminal; (b) diffuse away from the receptor site; (c) are enzymatically transformed into ineffective substances. (a) (b) 離 (c)

diffuse away from the receptor site; (c) are

12 II. Activation of the Postsynaptic Cell The postsynaptic cell's membrane potential is the result of temporal and spatial summation of the EPSPs and IPSPs at the many active excitatory and inhibitory synapses on the cell. 數行

temporal and spatial summation of the EPSPs and IPSPs

13 ( ) Excitatory Chemical Synapses 刺

14 ( ) Inhibitory Chemical Synapses

15 III. Synaptic Integration 錄

16 錄

17 The initial segment has a lower threshold than the threshold of the cell body and dendrites. 來

18 (a) 流離流了 (b) 流流了

19 IV. Synaptic Strength 率 (1) Presynaptic factors (a) Availability of neurotransmitter. 量 (b) Axon terminal calcium. 離度 (c) Activation of receptors on presynaptic terminal (i) presynaptic synapses (presynaptic inhibition or presynaptic facilitation). ( ) (ii) autoreceptor

離度 (c) Activation of receptors on presynaptic terminal (i)

20 (2) Postsynaptic factors (a) Multiple neurotransmitters (or cotransmitter) regulation. ( ) (b) Number of receptors (receptor desensitization). 數 ( )

21 A presynaptic (axo-axonic) synapse between axon terminal A and axon B. C is the final postsynaptic cell body.

22 Modification of Synaptic Transmission by Drugs and Disease (A) 數量 (B) (C) (D) (E) (F) (G) ( ) ( ) (H)

23 神神神

24 V. Neurotransmitters and Neuromodulators In general, neurotransmitters cause EPSPs and IPSPs, and neuromodulators cause, via second messengers, more complex metabolic effects in the postsynaptic cell. 更 The actions of neurotransmitters are usually faster than those of neuromodulators.

25 (I) Acetylcholine (1) Synthesis Choline + acetyl CoA A acetylcholine (2) Degradation acetylcholinesterase (3) Receptor (a) Nicotinic receptor ion channel 離 Cognitive functions in the brain (Alzheimer s disease) ( ) (b)muscarinic receptor couple with G protein G

26 力泌力神不刺神臨來療力

27 (II) Biogenic Amines (1)Catecholamines dopamine, norepnephrine, epinephrine. 茶 (a) Synthesis 酪 L- 酪

28 (b) Degradation Monoamine oxidase (inhibitors are used in the treatment of depression) ( 療 ) (c) Receptors for norepnephrine and epinephrine Alpha-adrenergic receptor Beta-adrenergic receptor (d) Functions Consciousness, mood, movement, blood pressure regulation, hormone release. 識狀

29 (2) Serotonin 力 (a) Synthesis Tryptophan Serotonin 力 (b) Functions Food intake, reproductive behavior, emotional states. 行狀

30 (III) Amino Acid Neurotransmitters Excitatory amino acids glutamate, aspartate Inhibitory amino acid GABA, glycine (IV) Neuropeptides Derived from large precursor proteins eg. Endogenous opioids, substance P P (V) Miscellaneous NO diffuses into intracellular fluid and activates guanylyl cyclase. ATP excitatory neurotransmitter

31 1. 率泌離 3. 兩 5. 離離 7. 度 6. 離,

32 Section D STRUCTURE OF THE NERVOUS SYSTEM

33 Structure of the Nervous System 1. 2.

34 I. Central Nervous System: Brain

35 (I) Forebrain (1) Cerebral cortex ( 參 ) 葉葉葉葉

36 (2) Subcortical nuclei basal ganglia ( 連路 ) (3) Diencephalon thalamus, hypothalamus ( 路參 ) ( 泌 )

37 (4) Limbic system ( 參行數 ) 葉

38 (II) Cerebellum The cerebellum plays a role in posture, movement, and some kinds of memory.

39 (III) Brainstem (1) Cell bodies in the reticular formation are absolutely essential for life. motor function, cardiovascular control, respiratory control, sleep, focus attention. 狀力 (2) The brainstem contains nuclei involved in processing information for 10 of the 12 pairs of cranial nerves 理

40 II. Central Nervous System: Spinal Cord

41 III. Peripheral Nervous System The peripheral nervous system consists of 43 paired nerves 12 pairs of cranial nerves and 31 pairs of spinal nerves

42 The efferent division of PNS is subdivided into (1) Somatic nervous system (motor neurons) innervate skeletal muscle, cell bodies are located in the brainstem or spinal cord. (2) Autonomic nervous system innervate smooth muscle, cardiac muscle. 滑

43 31 8 C 12 T 5 L 5 S 1 肋肋切

44 IV. Autonomic nervous system 滑

45 (a) The autonomic nervous system is divided into sympathetic (thoracolumbar division) and parasympathetic components (craniosacral division). () () 兩

47 (b) Sympathetic ganglia form two chains of ganglia sympathetic trunks, collateral ganglia. 兩 Parasympathetic ganglia lie within the organs or very close to the organs.

49 (c) The preganglionic neurons in both sympathetic and parasympathetic divisions release acetylcholine; the postganglionic parasympathetic neurons release mainly acetylcholine; and the postganglionic sympathetics release mainly norepinephrine. 泌泌泌 (d) The adrenal medulla is a hormonesecreting part of the sympathetic nervous system and secretes mainly epinephrine. 泌泌

50 不 (1)

51 (2) ( 量 )

52 不 (1)

53 (2) ( 量 )

54 V. Blood Supply, Blood-Brain Barrier Phenomena, and Cerebrospinal Fluid (1)Brain tissue depends on a continuous supply of glucose and oxygen for metabolism. 糖 (2) The brain ventricles and the space within the meninges are filled with cerebrospinal fluid, which is formed in the ventricles (choroids plexuses). 了 ( )

55 連

56 ( 藍 ) 流狀 -

61 (3) The chemical composition of the extracellular fluid of the CNS is closely regulated by the blood-brain barrier (tight junctions).

血管內裝置感染管制作業規範

血管內裝置感染管制作業規範念 LG5332 82 年 01 89 年 10 92 年 12 不念年年年錄力 1 行類力行更料行留刺精 2 留不切刺錄更刺療更益臨狀立路理更路若連更更路更路更度 3 更更路更更若更路路料更利料刺更料更料更料刺不留料了更更料料 4 刺更料刺立率料若不狀