【正文】 and there are some of each type in the brain. These terms are used because nicotine mimics the action of acetylcholine at nicotinic receptors, whereas muscarine, an alkaloid from the mushroom Amanita muscaria, mimics the action of acetylcholine at the muscarinic receptors. Acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons. In the peripheral nervous system acetylcholine plays a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. In the central nervous system acetylcholine is believed to be involved in learning, memory, and mood. Acetylcholine is synthesized from choline and acetyl coenzyme A through the action of the enzyme choline acetyltransferase and bees packaged into membranebound vesicles . After the arrival of a nerve signal at the termination of an axon, the vesicles fuse with the cell membrane, causing the release of acetylcholine into the synaptic cleft . For the nerve signal to continue, acetylcholine must diffuse to another nearby neuron or muscle cell, where it will bind and activate a receptor protein. There are two main types of cholinergic receptors, nicotinic and muscarinic. Nicotinic receptors are located at synapses between two neurons and at synapses between neurons and skeletal muscle cells. Upon activation a nicotinic receptor acts as a channel for the movement of ions into and out of the neuron, directly resulting in depolarization of the neuron. Muscarinic receptors, located at the synapses of nerves with smooth or cardiac muscle, trigger a chain of chemical events referred to as signal transduction. For a 。 in response to activation of this nerve supply, smooth muscle contracts (notably in the gut), the frequency of heart beat is slowed, and glands secrete. Acetylcholine is also an important transmitter at many sites in the brain at nervetonerve synapses. To understand how acetylcholine brings about a variety of effects in different cells it is necessary to understand membrane receptors. In postsynaptic membranes (those of the cells on which the nerve fibres terminate) there are many different sorts of receptors and some are receptors for acetylcholine. These are protein molecules that react specifically with acetylcholine in a reversible fashion. It is the plex of receptor bined with acetylcholine which brings about a biophysical reaction, resulting in the response from the receptive cell. Two major types of acetylcholine receptors exist in the membranes of cells. The type in skeletal muscle is known as ‘nicotinic’。 8 請您刪除一下內(nèi)容， O(∩ _∩ )O 謝謝?。?！ 2021 年中央電大期末復(fù)習(xí)考試小抄大全，電大期末考試必備小抄，電大考試必過小抄Acetylcholine is a neurotransmitter released from nerve endings (terminals) in both the peripheral and the central nervous systems. It is synthesized within the nerve terminal from choline, taken up from the tissue fluid into the nerve ending by a specialized transport mechanism. The enzyme necessary for this synthesis is formed in the nerve cell body and passes down the axon to its end, carried in the axoplasmic flow, the slow movement of intracellular substance (cytoplasm). Acetylcholine is stored in the nerve terminal, sequestered in small vesicles awaiting release. When a nerve action potential reaches and invades the nerve terminal, a shower of acetylcholine vesicles is released into the junction (synapse) between the nerve terminal and the ‘effector’ cell which the nerve activates. This may be another nerve cell or a muscle or gland cell. Thus electrical signals are converted to chemical signals, allowing messages to be passed between nerve cells or between nerve cells and nonnerve cells. This process is termed ‘chemical neurotransmission’ and was first demonstrated, for nerves to the heart, by the German pharmacologist Loewi in 1921. Chemical transmission involving acetylcholine is known as ‘cholinergic’. Acetylcholine acts as a transmitter between motor nerves and the fibres of skeletal muscle at all neuromuscular junctions. At this type of synapse, the nerve terminal is closely apposed to the cell membrane of a muscle fibre at the socalled motor end plate. On release, acetylcholine acts almost instantly, to cause a sequence of chemical and physical events (starting with depolarization of the motor endplate) which cause contraction of the muscle fibre. This is exactly what is required for voluntary muscles in which a rapid response to a mand is required. The action of acetylcholine is terminated rapidly, in around 10 milliseconds。（如主動參與游戲；帶著幼兒玩耍；引導(dǎo)小鴨子們 請小雞一起玩；引導(dǎo)新一輪游戲的進(jìn)行等。 參考答案： 1．對于小班幼兒來說，其表演游戲水平處于初級階段，口頭語言和肢體語言均不夠豐富，對生活現(xiàn)象的觀察和體驗也十分有限，因此，小雞小鴨游戲的任務(wù)不應(yīng)是要求幼兒的表演必須生動逼真，其主要任務(wù)應(yīng)該是重在培養(yǎng)幼兒參與表演游戲的熱情，促進(jìn)他們在表演中切實體驗游戲的快樂。當(dāng)家長來接時，孩子們都不愿離去。 故事剛講完，幾個調(diào)皮的小朋友就從寢室里拿出小雞小鴨的頭飾戴在頭上，其他小朋友見了也學(xué)他們的樣，開始嘰嘰嘰嘎嘎嘎地叫著進(jìn)行自由表演游戲，可是沒多久“小雞小鴨”們就開始嬉笑打鬧。一方面這是材料不夠所致，另一方面，也反映出教師沒有及時介入、引導(dǎo)。教師應(yīng)該在該區(qū)域放置一個材料比較豐富的“百寶箱”，讓幼兒有較多選擇的可能。 （ 3）在整個過程中，幼兒游戲態(tài)度積極，堅持性好，主動性強(qiáng)，能自主推動進(jìn)程的發(fā)展。尤其是欣欣，她說的“水還沒開呢”反映出她具備一定的生活經(jīng)驗。小玉和鵬鵬也來到了娃娃家區(qū)域，欣欣、云云和寧寧熱情地邀請他倆參加，五個小朋友一起像模像樣地涮起了火鍋?！? 又過了大約兩分鐘，寧寧說：“可以吃了，我都聞到香味了?！闭f著就要撈起來吃。在排隊等著理發(fā)呢。 好一會兒，欣欣都還沒回來?！? “哦，那我來拌調(diào)料吧?！闭f完就離開了娃娃家區(qū)域。” 欣欣說：“好吧，我給你做火鍋?！? 云云說：“你做火鍋吧。欣欣拿起杯子和勺子，有勺子在杯子里攪拌，一邊攪拌一邊喊道：“賣豆?jié){了！賣豆?jié){了！誰喝熱豆?jié){？” 云云走近他，問道：“你在干什么？” 欣欣回答：“我在熬豆?jié){呢。一段時間以來，在這個游戲區(qū)域的活動一直比較平淡。 四、案例分析題（ 25 分） ，分析活動情況，寫出觀察結(jié)論。 第四，注重玩具教育意義的開發(fā)以及玩具玩法的效果評價。 第三，應(yīng)對幼兒進(jìn)行玩具玩法指導(dǎo)。 第二，投放玩具和 游戲材料時充分考慮玩具的數(shù)量、種類及其搭配。 首先，應(yīng)根據(jù)幼兒的年齡特點提供適宜的玩具 。 2． 幼兒園玩教具 的 利用。 （ 5）創(chuàng)新性原則。 （ 4）經(jīng)濟(jì)性與可持續(xù)發(fā)展原則。 （ 3）科學(xué)性與教育性原則。 （ 2）藝術(shù)性與可玩性原則。 答 ：（ 1）安全性原則。 8． 本章的內(nèi)容實踐性、 操作性很強(qiáng)，需要結(jié)合各類游戲指導(dǎo)要求和策略進(jìn)行一定的案例分析練習(xí) ， 分析 四 種類型幼兒游戲活動指導(dǎo) 案例中教師的指導(dǎo)是否正確。一方面要在語言、常識、計算、體育等各科教學(xué)中充分運用規(guī)則游戲，特別是在小班更要廣泛開展，以提高幼兒學(xué)習(xí)的積極性、主動性，并獲得良好的效果。在游戲中，教師要注意督促兒童遵守規(guī)則，以保證游戲的順利開展和 7 游戲任務(wù)的完成。因此，在開始一個新的游戲之前，教師要以簡明生動的語言、適當(dāng)?shù)氖痉?，幫助幼兒學(xué)會游戲的玩法，掌握游戲的規(guī)則。對小班幼兒來說，游戲的規(guī)則要簡單交易于遵守，而中大班