肾素-血管紧张素系统怎样调节血压？
How does the renin-angiotensin system regulate blood pressure?
肾灌注下降时肾脏释放肾素，把血管紧张素原切成血管紧张素 I，再经血管紧张素转化酶（ACE）生成强效缩血管的角 II，升高血压并保钠保水。Guyton 与 Hall 把它列为长期血压调控的核心回路。
Low renal perfusion makes the kidney release renin, cleaving angiotensinogen to angiotensin I, then ACE forms vasoconstrictor angiotensin II, raising pressure and conserving salt and water. Guyton & Hall rank this as the core long-term pressure loop.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#肾素-血管紧张素 #血压 #ACE
人类如何仅凭约400种嗅觉受体识别成千上万种气味？
How can humans discriminate thousands of odors with only about 400 olfactory receptors?
嗅觉受体由人类基因组中最大的基因家族之一编码（约400个功能基因），每个嗅觉感觉神经元只表达一种受体，气味分子与受体结合后通过G蛋白激活cAMP信号通路，使神经元发放动作电位。表达同一种受体的神经元把轴突汇聚到嗅球中特定的嗅小球，形成一受体一小球的拓扑图谱。不同气味激活不同受体组合，大脑以组合编码的方式识别海量气味。此外嗅觉神经元是少数能终身再生的感觉神经元，并具有敏锐的浓度分辨能力。
Olfactory receptors are encoded by one of the largest gene families in the human genome (about 400 functional genes). Each olfactory sensory neuron expresses only one receptor; odorant binding activates the G-protein-cAMP pathway and generates action potentials. Neurons expressing the same receptor project their axons to a specific glomerulus in the olfactory bulb, producing a one-receptor-one-glomerulus topographic map. Different odorants activate different combinations of receptors, and the brain decodes countless odors by combinatorial coding. Olfactory neurons are among the few sensory neurons that regenerate throughout life, and the system can resolve small concentration differences.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Buck, Axel,《A novel multigene family may encode odorant receptors: A molecular basis for odor recognition》,Cell,1991 (DOI: 10.1016/0092-8674(91)90418-x)
Buck, Axel, 'A novel multigene family may encode odorant receptors: A molecular basis for odor recognition', Cell, 1991, DOI: 10.1016/0092-8674(91)90418-x
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1016/0092-8674(91)90418-x
#嗅觉受体 #组合编码 #嗅球
血红蛋白的协同结合如何提升氧气运输效率？
How does hemoglobin's cooperative binding improve oxygen transport?
血红蛋白四个亚基结合氧后构象变化提高其余亚基亲和力，使在肺部迅速饱和、在组织中又因构象转变易于释放，呈 S 形氧合曲线，实现高效装载与卸载。
Binding of O2 to one subunit induces a conformation that raises the affinity of the others, giving an S-shaped curve that loads O2 rapidly in the lungs and releases it readily in tissues.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
《生物化学》教材
Lehninger Biochemistry
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#血红蛋白 #协同 #氧运输
肾单位如何靠逆流倍增浓缩尿液？
How does the nephron concentrate urine via the countercurrent multiplier?
髓袢与集合管形成逆流系统，通过主动转运在髓质建立盐浓度梯度，抗利尿激素调节水重吸收，使尿液可被高度浓缩以保水。
The loop of Henle and collecting duct form a countercurrent system that builds a salt gradient in the medulla; ADH tunes water reabsorption so urine can be highly concentrated to conserve water.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肾单位 #逆流倍增 #保水
鱼鳃的逆流交换系统如何提高摄氧效率？
How does the countercurrent exchange in fish gills improve oxygen uptake?
水流与血流方向相反，使二者在各接触点始终保持氧分压差，鳃部血液能持续从水中摄取氧气，摄氧效率远高于顺流系统。
Water and blood flow in opposite directions, maintaining an oxygen partial-pressure gradient at every contact point so blood keeps extracting O2, achieving far higher uptake than parallel flow.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
《动物生理学》教材
Animal Physiology (Hill)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787040255287（豆瓣书目条目: 动物生理学）
#逆流交换 #鳃 #呼吸
激素是怎么“传递命令”的？为什么胰岛素出了问题会得糖尿病？
How do hormones "deliver orders," and why does a problem with insulin cause diabetes?
激素是由内分泌腺分泌、经血液运输到全身的化学信使，只有带对应受体的靶细胞才能响应。胰岛素属于肽类激素，与细胞膜受体结合后触发细胞内信号链，促使肌肉和脂肪细胞把葡萄糖转运入胞，从而降低血糖。1型糖尿病是免疫系统破坏胰岛B细胞，胰岛素几乎不能分泌；2型糖尿病则是受体对胰岛素不敏感，细胞“听不见命令”。两者都让葡萄糖滞留在血液里，长期高血糖会损伤血管、神经和肾脏。
Hormones are chemical messengers secreted by endocrine glands and carried through the blood; only target cells bearing the matching receptor can respond. Insulin is a peptide hormone: it binds a membrane receptor and triggers an intracellular signaling chain that makes muscle and fat cells transport glucose inside, lowering blood glucose. Type 1 diabetes arises when the immune system destroys the pancreatic beta cells, leaving almost no insulin; type 2 diabetes is insulin resistance, where cells fail to hear the order. In both cases glucose stays in the blood, and chronic high glucose damages blood vessels, nerves and kidneys.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#激素 #胰岛素 #糖尿病
压力感受器反射如何快速稳定血压？
How does the baroreceptor reflex rapidly stabilize blood pressure?
颈动脉窦和主动脉弓的压力感受器感知血压变化，经神经将信号送到延髓，血压高时减速心率并扩张血管，血压低时则反向调节，数秒内恢复。
Baroreceptors in the carotid sinus and aortic arch sense pressure changes and signal the medulla; rising pressure slows heart rate and dilates vessels, while falling pressure does the reverse, restoring pressure within seconds.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#压力感受器 #血压 #反射
肾脏是怎么把血液里的“垃圾”滤出来，又把有用的东西留下来的？
How does the kidney filter waste out of the blood while keeping the useful molecules?
肾脏的基本单位是肾单位，分三步工作。第一，肾小球滤过：血压把血液里的水、小分子（葡萄糖、氨基酸、无机盐、尿素）连同废物压过滤过膜，血细胞和大分子蛋白质被挡住留在血管里。第二，肾小管重吸收：管壁把几乎所有葡萄糖和氨基酸主动运回血液，按身体需要回收大部分水分和无机盐。第三，肾小管分泌：多余的离子、氢离子、药物被主动排进管腔。抗利尿激素和醛固酮根据身体水平衡调整水的重吸收量，最终形成的尿液就是浓缩后的多余水和废物。
The kidney's working unit is the nephron, which does three jobs. First, glomerular filtration: blood pressure pushes water and small molecules, including glucose, amino acids, salts and urea, through the filter membrane, while blood cells and large proteins are held back. Second, tubular reabsorption: the tubule wall actively hauls almost all glucose and amino acids back into the blood and reclaims most water and salts according to the body's needs. Third, tubular secretion: excess ions, hydrogen ions and drugs are actively pumped into the tubule. The hormones ADH and aldosterone tune how much water is reabsorbed, and the final urine is simply the surplus water and waste concentrated together.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肾单位 #滤过 #重吸收
什么是内环境稳态？
What is homeostasis?
内环境稳态指机体通过调节机制把体温、血糖、pH等内部条件维持在相对稳定范围的能力。例如出汗降温、胰岛素调节血糖都是稳态表现。稳态失衡往往意味着疾病。
Homeostasis is the body's ability to keep internal conditions such as temperature, blood sugar, and pH within a stable range through regulatory mechanisms. Sweating to cool down and insulin adjusting blood sugar are examples. Loss of homeostasis often signals disease.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#稳态 #调节 #平衡
什么是血液循环的双循环？
What is double circulation in the body?
人类等哺乳动物拥有肺循环和体循环两套回路：肺循环把缺氧血送到肺换气，体循环把含氧血送往全身。心脏的四个腔室把这两套血流完全分开，提高了供氧效率。这是温血动物维持高代谢的基础。
Mammals like humans have two circuits: pulmonary circulation sends oxygen-poor blood to the lungs, and systemic circulation delivers oxygen-rich blood to the whole body. The heart's four chambers keep these two flows separate, raising oxygen-delivery efficiency. This underpins the high metabolism of warm-blooded animals.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#双循环 #肺循环 #体循环
肾脏髓质里的"逆流倍增"是如何把尿液浓缩的？
How does the countercurrent multiplier in the kidney medulla concentrate urine?
肾髓质中，亨勒袢与集合管平行逆向流动形成"逆流倍增"：髓质间质由外向内盐浓度递增，集合管在抗利尿激素作用下对水通透，水被高渗间质抽走，从而浓缩尿液、减少水分丢失。
In the renal medulla, the loop of Henle and collecting ducts run in parallel counterflow to create a "countercurrent multiplier": the interstitial salt gradient rises from outer to inner medulla, and under antidiuretic hormone the collecting duct becomes water-permeable, letting water be pulled out to concentrate urine and conserve water.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#逆流倍增 #肾髓质 #尿液浓缩 #抗利尿激素
激素反馈调节是怎样维持体内稳态的？
How does hormonal feedback regulation maintain homeostasis?
多数内分泌轴采用负反馈：当某激素水平过高，会抑制上游腺体（如下丘脑、垂体）继续分泌，使其回落。例如甲状腺激素过多即抑制促甲状腺激素释放，从而把各项指标稳定在正常范围。
Most endocrine axes use negative feedback: when a hormone rises too high, it inhibits upstream glands such as the hypothalamus or pituitary, bringing levels back down. Excess thyroid hormone, for example, suppresses releasing signals so values stay within a normal range.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#激素 #负反馈 #内分泌 #稳态
长时程增强（LTP）为什么被认为是学习记忆的细胞基础？
Why is long-term potentiation (LTP) considered a cellular basis of learning and memory?
长时程增强指高频刺激突触后，该突触的传递效率持续数小时至数天的增强，最先在海马被Bliss和Lømo（1973）发现。其机制：突触前释放谷氨酸，激活突触后AMPA受体使膜去极化，Mg2+脱离NMDA受体，Ca2+大量流入突触后细胞，激活CaMKII等激酶，磷酸化并插入更多AMPA受体（早期LTP），并通过激活CREB等转录因子促进新蛋白合成、形成新突触（晚期LTP），实现持久增强。LTP的诱导和维持依赖海马，与空间记忆（如莫里斯水迷宫）和行为记忆高度相关，是记忆存储于突触连接改变这一假说的核心证据。
LTP is a long-lasting (hours to days) increase in synaptic strength following high-frequency stimulation, first described in the hippocampus by Bliss and Lømo (1973). Mechanistically, presynaptic glutamate activates postsynaptic AMPA receptors, depolarizing the membrane; Mg2+ leaves the NMDA receptor, allowing Ca2+ to flood the postsynaptic cell and activate kinases such as CaMKII, which phosphorylates and inserts more AMPA receptors (early LTP). Late LTP involves CREB-driven gene transcription, protein synthesis, and formation of new synapses, making the potentiation persistent. LTP induction requires the hippocampus and correlates with spatial memory (e.g., the Morris water maze) and behavioral memory, providing key evidence that memories are stored in changes of synaptic connections.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Bliss 与 Lømo,《Long‐lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path》,The Journal of Physiology,1973 (DOI: 10.1113/jphysiol.1973.sp010273)
Bliss and Lømo, 'Long‐lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path', The Journal of Physiology, 1973, DOI: 10.1113/jphysiol.1973.sp010273
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1113/jphysiol.1973.sp010273
#长时程增强 #NMDA受体 #突触可塑性
钠钾泵对神经细胞有什么重要性？
Why is the sodium-potassium pump important for nerve cells?
钠钾泵每消耗一个 ATP，就把三个钠离子泵出细胞、两个钾离子泵入，维持细胞膜内外约 -70 mV 的静息电位。这种离子梯度是神经元产生动作电位、传递信号的前提，也是许多物质继发性主动运输的能量来源。
The sodium-potassium pump uses one ATP to move three Na+ out and two K+ in, maintaining the roughly -70 mV resting potential across the membrane. This ion gradient is the basis for the action potential that lets neurons signal and powers much secondary active transport.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#钠钾泵 #静息电位 #动作电位 #ATP
为什么医生用小锤敲一下膝盖，小腿就会自动踢出去？
Why does your leg kick out when the doctor taps your knee with a little hammer?
这叫膝跳反射，是人体最快的“自动程序”。敲击拉伸了股四头肌，肌肉里的感受器（肌梭）立刻发出信号，经感觉神经直达脊髓，在那里直接换成运动神经指令，让肌肉收缩、小腿踢出。整个过程没经过大脑，所以快得几乎不需要时间思考，也正因如此它被用来检查神经通路是否完好。
This is the knee-jerk reflex, one of the body's fastest automatic programs. The tap stretches the quadriceps, and receptors inside the muscle (muscle spindles) fire a signal up sensory nerves to the spinal cord, which immediately switches to a motor command that makes the muscle contract and the leg kick. The brain is not involved, so it happens almost instantly, which is exactly why doctors use it to test whether neural pathways are intact.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Khan Academy（反射弧）
Khan Academy (reflex arc)
#膝跳反射 #肌梭 #反射弧
肾脏有什么功能？
What do the kidneys do?
肾脏像身体的过滤器，每天处理约180升原尿，把多余水分、废物和毒素变成尿液排出。它们还调节体内的盐、水和酸碱平衡。肾脏功能衰竭时需要透析或移植维持生命。
The kidneys act as the body's filters, processing about 180 liters of pre-urine each day and turning excess water, waste, and toxins into urine. They also regulate salt, water, and acid-base balance. When kidneys fail, dialysis or a transplant is needed to sustain life.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肾脏 #过滤 #尿液
肠道微生物组对人体健康有什么广泛影响？
What broad effects does the gut microbiome have on human health?
肠道菌群参与营养消化吸收、维生素合成、免疫发育和抵御病原，其失衡与肥胖、炎症和代谢疾病相关，是近年医学研究热点。
The gut microbiome aids digestion, vitamin synthesis, immune development and pathogen resistance; its imbalance links to obesity, inflammation and metabolic disease, making it a major research focus.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#微生物组 #肠道 #免疫
人体呼吸的本质是什么？
What is the essence of human respiration?
呼吸包括通气（肺与外界换气）和气体交换（肺泡与血液、血液与组织之间交换氧和二氧化碳）。其本质是细胞通过有氧呼吸把葡萄糖等底物氧化，释放能量并产生 ATP，二氧化碳作为废物被排出。
Respiration includes ventilation (air exchange with the environment) and gas exchange (oxygen and carbon dioxide moving between alveoli and blood, then blood and tissues). Its essence is cells oxidizing substrates like glucose through aerobic respiration to release energy as ATP, with carbon dioxide as a waste product.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#呼吸 #气体交换 #有氧呼吸 #ATP
人为什么会觉得饿？
Why do people feel hungry?
饥饿感由大脑的下丘脑调控，受血糖下降、胃排空和激素信号共同影响。胃分泌的饥饿素会向大脑发出进食信号。饱腹感则在血糖上升和肠道激素释放后产生。
The feeling of hunger is controlled by the hypothalamus in the brain, influenced by falling blood sugar, an empty stomach, and hormonal signals. The stomach releases ghrelin, which signals the brain to eat. A sense of fullness arises after blood sugar rises and gut hormones are released.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#饥饿 #下丘脑 #激素
为什么上台演讲前会心跳加速、手心出汗？
Why does your heart race and your palms sweat before a speech?
这是“战斗或逃跑”反应：大脑感受到紧张，交感神经被激活，同时肾上腺髓质释放肾上腺素和去甲肾上腺素。这些激素随血液到达全身，让心跳加快、血压升高、支气管扩张，血液重新分配给肌肉，汗腺也被刺激分泌。这套机制本来帮祖先在遇到危险时迅速行动，如今面对演讲和考试也会照样启动。
This is the fight-or-flight response. When your brain registers stress, the sympathetic nervous system switches on and the adrenal medulla releases epinephrine and norepinephrine. Carried by the blood, these hormones speed the heart, raise blood pressure, dilate the airways and redirect blood to muscles, while sweat glands are stimulated too. The mechanism evolved to let ancestors act instantly in danger, and it still fires for speeches and exams.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#战斗或逃跑 #肾上腺素 #交感神经
人类的基本味觉有哪几种？味觉受体是如何感知味道的？
What are the basic taste qualities in humans, and how do taste receptors detect them?
人类有五种基本味觉：甜、咸、酸、苦、鲜。舌面和口腔内的味蕾中，味觉受体细胞的微绒毛接触食物中的溶质：甜味由T1R2/T1R3受体感知，鲜味（umami）由T1R1/T1R3感知，苦味由T2R受体家族感知，咸和酸则主要通过离子通道介导。受体激活引起细胞去极化、释放递质，冲动经面神经、舌咽神经传至脑干孤束核，再投射到皮层味觉区。
Humans have five basic tastes: sweet, salty, sour, bitter, and umami. In taste buds on the tongue and oral cavity, microvilli of taste receptor cells contact solutes: sweetness is detected by the T1R2/T1R3 receptor, umami by T1R1/T1R3, bitterness by the T2R receptor family, while salty and sour tastes are mediated mainly by ion channels. Activation depolarizes the cell and releases neurotransmitter; the signals travel via the facial and glossopharyngeal nerves to the nucleus of the solitary tract in the brainstem, then to the gustatory cortex.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#味觉 #味蕾 #味觉受体
肺泡表面活性物质如何防止呼气末肺泡塌陷？
How does pulmonary surfactant prevent alveolar collapse at end-expiration?
表面活性物质由 II 型肺泡细胞分泌，降低肺泡表面张力，使小肺泡不因高表面张力而塌陷，并减少吸气做功。
Produced by type II pneumocytes, surfactant lowers alveolar surface tension so small alveoli do not collapse from high tension and inspiratory work is reduced.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#表面活性物质 #肺泡 #呼吸
血红蛋白如何运输氧气？
How does hemoglobin transport oxygen?
血红蛋白是红细胞中的含铁蛋白质，其血红素中的二价铁能可逆地结合一个氧分子。在肺部氧分压高时结合氧，在组织中氧分压低时释放氧，一分子血红蛋白最多可携带四个氧分子。
Hemoglobin is an iron-containing protein in red blood cells; the ferrous iron in its heme reversibly binds one oxygen molecule. It loads oxygen where partial pressure is high in the lungs and releases it where it is low in tissues, carrying up to four O2 per hemoglobin molecule.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#血红蛋白 #氧气运输 #血红素 #红细胞
心脏的“天然起搏点”窦房结有什么作用？
What is the role of the sinoatrial (SA) node, the heart's natural pacemaker?
窦房结位于右心房，由一群能自发产生电脉冲的细胞组成，规律地发出冲动使心脏收缩，决定正常心率。若窦房结功能异常，可能需要植入人工心脏起搏器。
Located in the right atrium, the sinoatrial node is a cluster of cells that spontaneously generate electrical impulses, rhythmically triggering heartbeats and setting the normal heart rate. If it fails, an artificial pacemaker may be implanted.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
医学生理学教材《盖顿生理学》（Guyton and Hall）；美国心脏协会（AHA）
Guyton and Hall Textbook of Medical Physiology; American Heart Association (AHA)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#窦房结 #心脏起搏 #心律
肌肉收缩的“肌丝滑动”是怎样的？
What is the 'sliding filament' mechanism of muscle contraction?
神经信号使钙离子释放，肌球蛋白头部沿肌动蛋白丝滑动，使肌节缩短；ATP供能，放松时肌丝复位。这就是肌肉产生力量的基础。
A nerve signal releases calcium so myosin heads walk along actin filaments, shortening the sarcomere; ATP powers it, and the filaments reset on relaxation—the basis of muscle force.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肌丝滑动 #肌球蛋白 #收缩
人体是如何把体温稳定保持在约37℃的？
How does the body keep its core temperature steady at about 37°C?
下丘脑是体温的"恒温器"：体温偏高时下令出汗、皮肤血管扩张散热；偏低时令肌肉颤抖产热、皮肤血管收缩保温。这套负反馈让核心体温稳定在约37℃，误差仅零点几度。
The hypothalamus acts as the body's thermostat: when core temperature rises it triggers sweating and skin vasodilation to shed heat, and when it falls it causes shivering and vasoconstriction to conserve heat. This negative feedback keeps core temperature near 37°C within a fraction of a degree.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#体温调节 #下丘脑 #负反馈 #稳态
内耳的前庭系统是如何感受身体的位置和运动的？
How does the vestibular system of the inner ear sense body position and motion?
前庭系统位于内耳，由三个互相垂直的半规管和两个耳石器官（椭圆囊、球囊）组成。半规管内的壶腹嵴毛细胞感受头部旋转角速度，内淋巴流动使顶帽偏转带动纤毛弯曲；耳石器官中的位觉斑毛细胞感受直线加速和头部倾斜，其上方覆盖着含碳酸钙的耳石（耳砂），重力使耳石牵拉毛细胞。毛细胞弯曲引发神经冲动，经前庭神经传至脑干前庭核和小脑，协调平衡和眼动反射（如前庭眼反射VOR）。
The vestibular system of the inner ear consists of three mutually perpendicular semicircular canals and two otolith organs (utricle and saccule). Cristae in the ampullae of the semicircular canals sense angular head rotation: endolymph flow deflects the cupula and bends hair-cell stereocilia. The maculae of the otolith organs sense linear acceleration and head tilt; they are covered by a membrane bearing calcium carbonate otoliths whose gravity pulls bend the hair cells. Bending of hair cells generates impulses carried by the vestibular nerve to the vestibular nuclei and cerebellum, coordinating balance and eye reflexes such as the vestibulo-ocular reflex.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#前庭系统 #半规管 #耳石器官
胰岛素如何调节人体的血糖浓度？
How does insulin regulate blood glucose levels in the body?
进食后血糖升高，胰腺的 β 细胞分泌胰岛素，促使肝脏、肌肉和脂肪细胞摄取并储存葡萄糖，从而降低血糖。胰岛素分泌不足或作用受阻会引起糖尿病。
After meals, rising blood glucose triggers the pancreas's beta cells to secrete insulin, which prompts liver, muscle, and fat cells to take up and store glucose, lowering blood sugar. Insufficient insulin or resistance to it causes diabetes.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#胰岛素 #血糖调节 #糖尿病
血液在体内是怎么“跑圈”的？为什么说人是双循环？
How does blood circulate around the body, and why do we speak of double circulation?
人的血液循环有两条路线串联成“8”字形。肺循环：右心室把缺氧血泵到肺，在肺泡处交换气体变成富氧血回到左心房。体循环：左心室把富氧血泵向全身各器官，组织细胞拿走氧和营养、留下二氧化碳，静脉再把缺氧血送回右心房。这样心脏两套泵各司其职，血压和流速才有保障。
Human blood flow forms a figure-eight of two circuits. In the pulmonary circuit, the right ventricle pumps deoxygenated blood to the lungs, where gas exchange at the alveoli makes it oxygen-rich before it returns to the left atrium. In the systemic circuit, the left ventricle pumps oxygen-rich blood to every organ; tissues take up oxygen and nutrients and deposit carbon dioxide, and veins carry the deoxygenated blood back to the right atrium. With two pumps handling each loop, blood pressure and flow are kept reliable.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
《普通生物学》(陈阅增)
General Biology (Chen Yuezeng)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9787040583151（豆瓣书目条目: 陈阅增普通生物学）
#肺循环 #体循环 #心脏
闸门控制理论是如何解释疼痛可以被触觉刺激减轻的？
How does the gate control theory explain why touch can reduce pain?
闸门控制理论由Melzack和Wall于1965年提出，认为脊髓背角中的抑制性中间神经元像一个闸门：粗（Aβ）纤维传导触压等非伤害信号，细（Aδ、C）纤维传导伤害性痛信号，二者在背角汇聚并竞争。揉搓、按摩等强触觉刺激兴奋粗纤维，抑制细纤维向大脑的传递（关闭闸门），从而缓解疼痛。痛觉还受大脑下行通路的调节，脑内释放的内啡肽、脑啡肽等内源性阿片肽可抑制痛觉传递。
The gate control theory, proposed by Melzack and Wall in 1965, holds that inhibitory interneurons in the spinal dorsal horn act as a gate: large (Aβ) fibers conduct touch and pressure, while small (Aδ, C) fibers conduct nociceptive signals, and the two converge and compete in the dorsal horn. Strong tactile stimulation such as rubbing activates large fibers, which inhibits transmission from small fibers to the brain (closing the gate) and relieves pain. Pain is also modulated by descending pathways from the brain, where endogenous opioids such as endorphins and enkephalins suppress pain transmission.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#痛觉 #闸门控制理论 #内啡肽
消化系统的任务是什么？
What is the job of the digestive system?
消化系统把食物分解成小分子，使养分能被血液吸收并运送到全身。它包括口腔、胃、小肠和大肠等器官，并依赖肝脏和胰脏的消化液。剩余的废物最终形成粪便排出。
The digestive system breaks food into small molecules so nutrients can be absorbed into the blood and carried everywhere. It includes the mouth, stomach, small and large intestines, relying on digestive juices from the liver and pancreas. Leftover waste becomes feces and is expelled.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#消化系统 #吸收 #营养
为何窦房结被称为心脏的天然起搏点？
Why is the SA node called the heart's natural pacemaker?
窦房结细胞自律性最高，能自发去极化产生节律冲动并经传导系统扩散至全心，决定正常心跳频率，故称天然起搏点。
SA node cells have the highest automaticity, spontaneously depolarizing to generate rhythmic impulses that spread through the conduction system to set the normal heart rate, hence the natural pacemaker.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#窦房结 #起搏 #心律
人体血红蛋白与胎儿血红蛋白在氧亲和力上有何差异及意义？
How do adult and fetal hemoglobin differ in oxygen affinity and why does it matter?
胎儿血红蛋白（HbF）对氧的亲和力高于成人血红蛋白（HbA），因其与 2,3-BPG 结合较弱，使氧气能从母体血液更有效地转运给胎儿，保障宫内供氧。
Fetal hemoglobin (HbF) has higher oxygen affinity than adult HbA because it binds 2,3-BPG more weakly, enabling efficient oxygen transfer from maternal blood to the fetus and securing prenatal oxygenation.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#胎儿血红蛋白 #氧亲和力 #2,3-BPG
胃怎样消化蛋白质？
How does the stomach digest protein?
胃壁分泌盐酸营造强酸环境并激活胃蛋白酶原成为胃蛋白酶，后者切断蛋白质肽键；黏液层与碳酸氢盐保护胃壁自身不被消化。Guyton 与 Hall 与 Lehninger 均描述了这一酶原激活机制。
The stomach secretes acid to activate pepsinogen into pepsin, which cleaves protein peptide bonds; a mucus-bicarbonate layer protects the wall itself. Guyton & Hall and Lehninger describe this zymogen activation.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall《医学生理学》；Lehninger《生物化学原理》
Guyton & Hall, Textbook of Medical Physiology; Lehninger, Principles of Biochemistry
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#胃蛋白酶 #盐酸 #蛋白质消化
肺怎样交换氧气和二氧化碳？
How do the lungs exchange oxygen and carbon dioxide?
肺泡壁极薄且表面积巨大，血液与空气仅隔数微米，O₂ 顺分压差扩散入血、CO₂ 扩散出肺，由血红蛋白载运。West 的《呼吸生理学》用分压差与通气/血流匹配解释了高效交换。
Alveoli have an enormous, ultrathin surface so blood and air are microns apart; O₂ diffuses down its partial-pressure gradient into blood and CO₂ out, carried by hemoglobin. West's 'Respiratory Physiology' explains the efficiency via pressure gradients and ventilation/perfusion matching.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall《医学生理学》；West《呼吸生理学》
Guyton & Hall, Textbook of Medical Physiology; West, Respiratory Physiology
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#肺泡 #气体交换 #分压
声波进入耳朵后是如何转变成神经信号的？
How is sound converted into neural signals once it enters the ear?
声波经外耳道引起鼓膜振动，听小骨（锤骨、砧骨、镫骨）以杠杆作用放大声压并将振动传导至卵圆窗，使耳蜗内淋巴液振动。基底膜随之波动，其上毛细胞的纤毛因剪切力弯曲，打开机械门控离子通道，细胞去极化释放递质，使听神经纤维产生动作电位传入听觉皮层。基底膜从基部到顶端对不同频率敏感：高频刺激靠近基底部，低频刺激靠近顶部。
Sound waves traveling down the ear canal vibrate the tympanic membrane; the ossicles (malleus, incus, stapes) amplify the pressure and transmit vibration to the oval window, setting the cochlear fluid in motion. The basilar membrane undulates, bending the stereocilia of hair cells, which opens mechanically gated ion channels and depolarizes the cells; they release neurotransmitter, and auditory nerve fibers fire action potentials to the auditory cortex. The basilar membrane is tonotopically organized: high frequencies excite the base, low frequencies the apex.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#听觉 #耳蜗 #毛细胞
肾脏是如何过滤血液并形成尿液的？
How do kidneys filter blood and form urine?
肾脏中的肾单位以肾小球和鲍曼囊为起点，利用血压将血液中的水、小分子物质和代谢废物滤出，形成原尿。随后肾小管重新吸收葡萄糖、离子和大部分水分，最终浓缩成尿液排出。
In the nephron, the glomerulus and Bowman's capsule use blood pressure to filter water, small molecules, and metabolic wastes from the blood into an initial filtrate. The renal tubules then reabsorb glucose, ions, and most water, concentrating the remainder into urine.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肾脏 #肾单位 #尿液形成
消化系统是怎样把食物变成营养的？
How does the digestive system turn food into nutrients?
消化系统通过机械咀嚼和酶的化学分解，把大分子食物逐步拆解成可吸收的小分子。胃和小肠分别用酸和消化酶处理食糜，小肠绒毛再把葡萄糖、氨基酸等吸收进血液，残渣形成粪便排出。
The digestive system uses mechanical chewing and chemical enzymes to break large food molecules step by step into absorbable small ones. The stomach and small intestine process chyme with acid and enzymes, and intestinal villi absorb glucose, amino acids, and more into the blood, while residue leaves as feces.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#消化系统 #消化酶 #小肠 #吸收
血脑屏障依靠哪些结构特点保护中枢神经？
What structural features let the blood-brain barrier protect the CNS?
脑毛细血管内皮细胞以紧密连接封闭、几乎无窗孔并由周细胞和星形胶质细胞脚板包裹，限制大多数大分子与细胞被动扩散，只允许脂溶性小分子等选择性通过。
Brain capillary endothelia are sealed by tight junctions, lack fenestrations and are enveloped by pericytes and astrocyte end-feet, blocking passive diffusion of most molecules and permitting only selective passage such as lipophilic small molecules.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#血脑屏障 #紧密连接 #中枢神经
肺没有肌肉，它是怎么被“带动”呼吸的？
Lungs have no muscles of their own, so what drives breathing?
呼吸靠的是胸腔的容积变化。吸气时膈肌收缩下降、肋间肌把肋骨上提，胸腔扩大、内部气压低于大气压，空气就被“吸”进来；呼气时这些肌肉放松，胸腔回缩把气体挤出去。气体交换发生在肺泡：肺泡壁极薄又紧贴毛细血管，氧气和二氧化碳靠浓度差自由扩散互换，肺泡的数量庞大，总面积相当于半个网球场。
Breathing is driven by changes in chest volume. When you inhale, the diaphragm contracts downward and the rib muscles lift the ribs, expanding the chest so pressure inside falls below atmospheric pressure and air is sucked in; when the muscles relax, the chest recoils and pushes air out. Gas exchange happens in the alveoli: their walls are paper-thin and wrapped in capillaries, so oxygen and carbon dioxide simply diffuse down their concentration gradients, and the enormous number of alveoli gives a surface area like half a tennis court.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#膈肌 #肺泡 #气体扩散
视网膜中的视杆细胞和视锥细胞在功能上有哪些分工？
How do rod and cone photoreceptors in the retina divide labor functionally?
视杆细胞对光极为敏感，负责暗光（夜视）下感知明暗，不能分辨颜色，主要分布在视网膜周边；视锥细胞对光敏感性较低，负责明亮环境下的精细视觉和颜色分辨，集中分布在黄斑中央凹。视杆细胞损伤会导致夜盲症，视锥细胞缺失或异常则影响色觉（如红绿色盲）。
Rods are extremely sensitive to light and mediate black-and-white vision in dim light (night vision); they cannot distinguish colors and are concentrated in the peripheral retina. Cones are less light-sensitive but provide sharp, color vision in bright light and are packed in the fovea of the macula. Damage to rods causes night blindness; loss or defects of cones impair color vision, as in red-green color blindness.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#视杆细胞 #视锥细胞 #色觉
心脏有什么作用？
What does the heart do?
心脏是一台肌肉泵，不停地把血液送往全身，输送氧气和养分并带走废物。它通过血管构成的循环系统与肺、肾等器官相连。成年人安静时每分钟大约跳60到100次。
The heart is a muscular pump that continuously sends blood throughout the body, delivering oxygen and nutrients and carrying away waste. It connects via blood vessels to organs like the lungs and kidneys in a circulatory system. At rest an adult heart beats about 60 to 100 times per minute.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#心脏 #血液循环 #泵
我们为什么要用肺呼吸？
Why do we breathe with our lungs?
肺像一对海绵样的气囊，吸气时把氧气收进血液，再把身体产生的二氧化碳呼出去。血液把氧气送到全身每一个细胞，让它们有能量工作，所以呼吸对活着非常重要。
The lungs are like a pair of spongy air sacs that pull oxygen into the blood as we breathe in and push out the carbon dioxide our bodies make. Blood carries that oxygen to every cell so they have energy to work, which is why breathing is vital to staying alive.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肺 #呼吸 #氧气 #二氧化碳
肾脏是怎样把血液过滤成尿液的？
How do kidneys filter blood into urine?
血液流经肾小球的滤网，水和小分子进入肾小囊，肾小管再重吸收有用物质、分泌废物，最终浓缩成尿液排出体外。
Blood is filtered at the glomerulus, where water and small molecules enter the capsule; the tubule then reabsorbs useful substances and secretes wastes, concentrating urine for excretion.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肾脏 #过滤 #尿液
心脏的主要作用是什么？
What is the main function of the heart?
心脏是一个不停跳动的肌肉泵，把血液输送到全身，把氧气和营养物质带给细胞，并把二氧化碳等废物带走。它分为左右两侧，分别推动肺循环和体循环，维持生命活动的运转。
The heart is a muscular pump that beats continuously to send blood throughout the body, delivering oxygen and nutrients to cells and carrying away waste like carbon dioxide. Divided into left and right sides, it drives pulmonary and systemic circulation to keep the body running.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 3 条独立证据
来源 · Source
Guyton 与 Hall，《医学生理学教科书》（第13版，Elsevier，2016）
Guyton & Hall, Textbook of Medical Physiology (13th ed., Elsevier, 2016)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-323-59712-8 · 核验依据 2 ISBN 978-1-4557-4377-3 (3rd ed., Elsevier) · 核验依据 3 ISBN 978-1-319-45541-5 (8th ed., Macmillan Learning)
#心脏 #血液循环 #泵 #氧气
人为什么会流汗？
Why do people sweat?
出汗是身体降温的方式：汗腺把水分排到皮肤表面，水分蒸发时带走热量。运动或天气炎热时出汗会增多。及时补水能避免脱水。
Sweating is the body's way to cool down: glands release water onto the skin, and as it evaporates, heat is carried away. Sweating increases during exercise or hot weather. Replenishing water in time prevents dehydration.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#出汗 #降温 #体温
肺部是如何完成氧气和二氧化碳交换的？
How do the lungs carry out the exchange of oxygen and carbon dioxide?
空气进入肺泡后，氧气穿过极薄的肺泡壁和毛细血管壁扩散进入血液，同时二氧化碳从血液扩散到肺泡并随呼气排出。庞大的肺泡表面积（约 70 平方米）使这种气体交换高效进行。
When air reaches the alveoli, oxygen diffuses across the thin alveolar and capillary walls into the blood, while carbon dioxide diffuses from blood into the alveoli to be exhaled. The vast alveolar surface area (~70 m²) makes this exchange highly efficient.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#肺泡 #气体交换 #呼吸
我们的肌肉是怎么动起来的？
How do our muscles make us move?
肌肉里有无数细小的肌纤维；大脑发出指令后，神经把信号送到肌肉，钙离子释放让肌纤维像拉链一样相互滑动、收缩，于是手和脚就能动起来。肌肉工作靠消耗能量（ATP）。
Muscles are made of countless tiny fibers; when the brain sends a command, nerves deliver the signal, calcium is released, and the fibers slide past each other like a zipper to contract—so our hands and feet can move. Muscles run on energy stored as ATP.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Marieb 与 Hoehn，《人体解剖生理学》（第11版，Pearson，2018）
Marieb & Hoehn, Human Anatomy & Physiology (11th ed., Pearson, 2018)
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-13-476023-0 (11th ed., Pearson)
#肌肉收缩 #肌纤维 #运动 #ATP
为什么人运动后会心跳加快？
Why does the heart beat faster after exercise?
运动时肌肉需要更多氧气和能量，心脏便加快跳动来输送更多含氧血。同时呼吸加深加快，排出更多二氧化碳。休息后心率会慢慢恢复正常。
During exercise muscles need more oxygen and energy, so the heart beats faster to deliver more oxygen-rich blood. Breathing also deepens and quickens to expel more carbon dioxide. After rest the heart rate gradually returns to normal.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Urry 等,《Campbell Biology》第11版,Pearson,2017
L. A. Urry et al., Campbell Biology, 11th ed., Pearson, 2017
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-13-409341-3 (11th ed., Pearson)
#运动 #心率 #氧气