電大作業(yè)閱讀與寫(xiě)作基礎(chǔ)形成性考核冊(cè)參考答案-展示頁(yè)
2025-06-15 11:01本頁(yè)面
【正文】 stand 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’。 見(jiàn)《大學(xué)語(yǔ)文》 P215— 216 請(qǐng)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(guò)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。 見(jiàn)《大學(xué)語(yǔ)文》 P225— 226 《陰翳禮贊》（節(jié)選）作者對(duì)日本建筑“陰翳之美”是怎樣品味的？對(duì)美的總體和諧是如何闡述的？ 見(jiàn)《大學(xué)語(yǔ)文》 P247— 248 《鄉(xiāng)村》中作者描繪的鄉(xiāng)村圖景特點(diǎn)，從中反映出作者對(duì)生活理想怎樣的追求與思考？ 見(jiàn)《大學(xué)語(yǔ)文》 P261— 262 三、分析題 分析《故鄉(xiāng)的食物》（節(jié)選）文中故鄉(xiāng)食物的特點(diǎn)及其寫(xiě)作方法。葛朗臺(tái)》，《幻滅》 1《戰(zhàn)爭(zhēng)與和平》，《安娜 見(jiàn)《大學(xué)語(yǔ)文》 P133— 134 分析張愛(ài)玲《談音樂(lè)》一文所表現(xiàn)出的人生態(tài)度。 見(jiàn)《大學(xué)語(yǔ)文》 P152 簡(jiǎn)述沈從文《老伴》的主要內(nèi)容。 見(jiàn)《大學(xué)語(yǔ)文》 P88— 89 《湖心亭看雪》是如何把寫(xiě)景、記事與抒情融為一體的？ 見(jiàn)《大學(xué)語(yǔ)文》 P103— 104 作業(yè) 3 一、填空題 “革命文學(xué)” “中國(guó)左翼作家聯(lián)盟” 《之夜》，《家》，《駱駝祥子》 現(xiàn)代話(huà)劇成熟 《生死場(chǎng)》 “新感覺(jué)派” “中華全國(guó)文藝界抗敵協(xié)會(huì) 《華威先生》，《在其香居茶館 里》 路翎 艾青
試題試卷相關(guān)推薦
鄂ICP備17016276號(hào)-1