【正文】 鴨 離園活動時間，教室里還有十幾位小朋友，他們圍坐在老師的周圍，聽老師講《小雞小鴨》的故事。 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。 這次游戲活動歷時近一個小時，幼兒們始終興致勃勃，樂此不疲。當(dāng)家長來接時，孩子們都不愿離去。 在教師的再三要求下，同時保證明天還組織孩子們游戲時，小朋友們才同意結(jié)束活動。 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。 2．在這個案例中，教師不是把自己置于導(dǎo)演者的地位，而是在幼兒自發(fā)的游戲活動中一直充當(dāng)著游戲的支持者、引導(dǎo)者和參與者的角色。（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。）教師充分尊重幼兒在游戲活動中的主體地位，善于創(chuàng)設(shè)民主平等的游戲環(huán)境（如用商量的口吻請小朋友同意自己參與游戲，請小朋友給自己分配角色），并且善于觀察孩子們的興趣與需求，推進(jìn)游戲順利有效的進(jìn)行（如小雞沒有興趣時及時邀請同小鴨們一起玩），從而使幼兒獲得心理滿足，激發(fā)和保護(hù)了幼兒學(xué)習(xí)表演的愿望。 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。 an enzyme (cholinesterase) breaks the transmitter down into choline and an acetate ion. The choline is then available for reuptake into the nerve terminal. These same principles apply to cholinergic transmission at sites other than neuromuscular junctions, although the structure of the synapses differs. In the autonomic nervous system these include nervetonerve synapses at the relay stations (ganglia) in both the sympathetic and the parasympathetic divisions, and the endings of parasympathetic nerve fibres on nonvoluntary (smooth) muscle, the heart, and glandular cells。 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’。 in glands, smooth muscle, and the heart they are ‘muscarinic’。 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