【TED】荷尔蒙是如何工作的？
中英文稿
在我们的一生中， 身体会经历一系列奇特的变化： 我们成长， 经历青春期， 许多人产下后代。 在这些变化的背后， 内分泌系统担任着指挥家的角色。 除了生长和性成熟以外， 内分泌系统还负责调解你的睡眠 和心跳的节奏， 它的影响延伸到 你身体里的每个细胞。
内分泌系统依靠 这三种东西的互动： 腺体、 荷尔蒙 以及数以万亿计的细胞受体。 首先，你的身体里有 几个生产荷尔蒙的腺体。 大脑里有三个， 身体其他部分有七个。 每个腺体都被血管网所包围， 腺体从血管网中获取 制造荷尔蒙的原材料。 这些荷尔蒙随后被腺体排出， 通常是排放到血液中。
从这里开始，每一个荷尔蒙 都需要以一种细胞为目标， 这样才能造成一个特定的身体变化。 在寻找目标的时候， 细胞受体帮了大忙， 它们是细胞表面特殊的蛋白质。 当血液流过时， 这些细胞受体能辨识特定的荷尔蒙， 然后跟它们配对结合。 这时， 荷尔蒙和细胞受体的结合 会引起一系列的反应， 像是增加或减少细胞内特定的过程， 来改变细胞的行为。
通过一次将数百万个细胞 暴露在精心调节数量的激素中， 内分泌系统驱动了了 人体内大规模的变化。
以甲状腺和 它分泌的两种荷尔蒙， 三碘甲状腺氨酸和甲状腺素为例。 这些荷尔蒙会达到 身体的大部分细胞， 这会影响细胞消耗能量的速度， 以及细胞工作的速度， 进而调节身体的每一个动作， 像是呼吸速度、 心跳、 体温 和消化。
荷尔蒙在一段时间有着最明显， 也是人们最熟悉的影响， 那就是青春期。 对于男性来说，青春期开始于 睾丸开始分泌睾丸素。 这促成了性器官的逐渐发育， 胡须生长， 以及声音变低沉， 还有身高增长。 对于女性来说，卵巢开始分泌 雌性激素意味着女性生理成年， 从而帮助身体发育， 使得臀部变宽， 子宫壁变厚， 帮助身体为怀孕或月经做好准备。
一个对于内分泌系统 长期以来的误解是， 男性荷尔蒙和女性荷尔蒙 是完全不一样的。 但事实上，男性和女性体内 都会分泌睾丸素和雌性激素， 只是量有所不同。 这两种荷尔蒙在怀孕的过程中 扮演着不同的角色， 此外还有其他 10 种荷尔蒙 一起确保胚胎的发育， 使人能够生育， 以及帮助妈妈哺育孩子。
荷尔蒙周期性的变化 与心情的波动也有联系。 这是因为荷尔蒙可以影响 化学物质在脑部的生产， 像是血清素。 当化学物质的浓度改变时， 也有可能造成心情的变化。 但是不是说荷尔蒙拥有 支配我们的无限力量。
它们常常被视为我们 行为的主要控制者， 使我们在它们面前没有任何自由， 尤其是在青春期的时候。 但是研究表明，我们的行为是 受很多因素协同控制的， 包括大脑和它的神经递质， 我们的荷尔蒙， 以及很多的社会因素。 内分泌系统的主要功能 是调节我们的身体， 而不是控制我们。
有时候，疾病、 压力、 甚至饮食都可以破坏这个调节功能， 改变腺体分泌荷尔蒙的量 或者是改变细胞 对荷尔蒙的反应方式。
糖尿病是最常见的荷尔蒙紊乱之一， 这是由胰腺分泌 的胰岛素过少引起的， 胰岛素就是一种控制血糖的荷尔蒙。 甲状腺机能减退和甲状腺机能亢进 是由甲状腺分泌过少或者 过多的甲状腺荷尔蒙引起的。 当体内甲状腺荷尔蒙 过少的时候，心率会下降， 人体会疲劳, 出现抑郁症状， 当甲状腺荷尔蒙过多， 会出现体重减少， 失眠， 易怒的现象。
但是大多数时候， 内分泌系统都能将 身体保持在一个平衡的状态。 通过不间断的荷尔蒙调节， 让我们的身体不断发生改变， 最后把我们塑造成现在的样子。
Over the course of our lifetimes, our bodies undergo a series of extraordinary metamorphoses: we grow, experience puberty, and many of us reproduce. Behind the scenes, the endocrine system works constantly to orchestrate these changes. Alongside growth and sexual maturity, this system regulates everything from your sleep to the rhythm of your beating heart, exerting its influence over each and every one of your cells.
The endocrine system relies on interactions between three features to do its job: glands, hormones, and trillions of cell receptors. Firstly, there are several hormone-producing glands: three in your brain, and seven in the rest of your body. Each is surrounded by a network of blood vessels, from which they extract ingredients to manufacture dozens of hormones. Those hormones are then pumped out in tiny amounts, usually into the bloodstream.
From there, each hormone needs to locate a set of target cells in order to bring about a specific change. To find its targets, it’s helped along by receptors, which are special proteins inside or on the cell’s surface. Those receptors recognise specific hormones as they waft by, and bind to them. When this happens, that hormone-receptor combination triggers a range of effects that either increase or decrease specific processes inside the cell to change the way that cell behaves.
By exposing millions of cells at a time to hormones in carefully-regulated quantities, the endocrine system drives large-scale changes across the body.
Take, for instance, the thyroid and the two hormones it produces, triiodothyronine and thyroxine. These hormones travel to most of the body’s cells, where they influence how quickly those cells use energy and how rapidly they work. In turn, that regulates everything from breathing rate to heartbeat, body temperature, and digestion.
Hormones also have some of their most visible—and familiar—effects during puberty. In men, puberty begins when the testes start secreting testosterone. That triggers the gradual development of the sexual organs, makes facial hair sprout, and causes the voice to deepen and height to increase. In women, estrogen secreted from the ovaries signals the start of adulthood. It helps the body develop, makes the hips widen, and thickens the womb’s lining, preparing the body for menstruation or pregnancy.
An enduring misconception around the endocrine system is that there are exclusively male and female hormones. In fact, men and women have estrogen and testosterone, just in different amounts. Both hormones play a role in pregnancy, as well, alongside more than 10 other hormones that ensure the growth of the fetus, enable birth, and help the mother feed her child.
Such periods of hormonal change are also associated with fluctuations in mood. That’s because hormones can influence the production of certain chemicals in the brain, like serotonin. When chemical levels shift, they may cause changes in mood, as well. But that’s not to say that hormones have unlimited power over us.
They’re frequently viewed as the main drivers of our behavior, making us slaves to their effects, especially during puberty. But research shows that our behavior is collectively shaped by a variety of influences, including the brain and its neurotransmitters, our hormones, and various social factors. The primary function of the endocrine system is to regulate our bodily processes, not control us.
Sometimes disease, stress, and even diet can disrupt that regulatory function, however, altering the quantity of hormones that glands secrete or changing the way that cells respond.
Diabetes is one of the most common hormonal disorders, occurring when the pancreas secretes too little insulin, a hormone that manages blood sugar levels. And hypo- and hyperthyroidism occur when the thyroid gland makes too little or too much thyroid hormone. When there’s too little thyroid hormone, that results in a slowed heart rate, fatigue, and depression, and when there’s too much thyroid hormone, weight loss, sleeplessness, and irritability.
But most of the time, the endocrine system manages to keep our bodies in a state of balance. And through its constant regulation, it drives the changes that ultimately help us become who we are.
