1.5 体内平衡和人体
章节大纲
-
What happens if stability is disrupted?
::如果稳定中断怎么办?Remove one stone and the whole arch collapses. The same is true for the . All the systems work together to maintain stability or homeostasis. Disrupt one system, and the whole body may be affected.
::移除一块石头和整个拱门的崩塌。对于 . . . . . . . . . . . . . . . . 所有系统 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Homeostasis
::常态The human body is made up of trillions of that all work together for the maintenance of the entire organism . While cells, tissues , and organs may perform very different functions, all the cells in the body are similar in their metabolic needs. Maintaining a constant internal environment by providing the cells with what they need to survive (oxygen, nutrients , and removal of waste) is necessary for the well-being of both individual cells and the entire body. The many processes by which the body controls its internal environment are collectively called homeostasis. The complementary activity of major body systems maintains homeostasis.
::人体由数万亿个细胞组成,共同维持整个有机体。细胞、组织和器官可能发挥非常不同的功能,但身体中的所有细胞在代谢需要方面都相似。通过向细胞提供生存所需的物质(氧、营养素和废物的清除)来保持一个稳定的内部环境,这对个体细胞和整个身体的福祉都是必要的。身体控制其内部环境的许多过程被统称为“自闭症 ” 。主要身体系统的补充活动保持了自闭症。Homeostasis refers to stability, balance , or equilibrium within a cell or the body. It is an organism’s ability to keep a constant internal environment. Homeostasis is an important characteristic of living things. Keeping a stable internal environment requires constant adjustments as conditions change inside and outside the cell. The adjusting of systems within a cell is called homeostatic regulation. Because the internal and external environments of a cell are constantly changing, adjustments must be made continuously to stay at or near the set point (the normal level or range). Homeostasis should be thought of as a dynamic equilibrium rather than a constant, unchanging state.
::恒定状态是指细胞或身体内部的稳定性、平衡或平衡。它是有机体保持一个稳定的内部环境的能力。恒定状态是生活事物的一个重要特征。随着细胞内外条件的变化,保持一个稳定的内部环境需要不断的调整。细胞内部系统的调整被称为自定状态。由于细胞的内部和外部环境不断变化,必须不断进行调整,以保持或接近设定点(正常水平或范围 ) 。 恒定状态应被视为动态平衡,而不是恒定的、不变的状态。Feedback Regulation Loops
::B. 条例循环The plays an important role in homeostasis because regulate the activity of . The release of hormones into the is controlled by a stimulus . The stimulus either causes an increase or a decrease in the amount of hormone secreted. The response to a stimulus changes the internal conditions and may itself become a new stimulus. This self-adjusting mechanism is called feedback regulation.
::激素的释放由刺激措施控制。刺激措施要么导致激素的增加,要么导致激素数量的减少。 对刺激措施的反应会改变内部条件,本身也可能成为新的刺激措施。这种自我调整机制被称为反馈调节。Feedback regulation occurs when the response to a stimulus has some kind of effect on the original stimulus. The type of response determines what the feedback is called. Negative feedback occurs when the response to a stimulus reduces the original stimulus. Positive feedback occurs when the response to a stimulus increases the original stimulus.
::当对刺激措施的反应对最初的刺激措施产生某种影响时,就会出现反馈监管。反应类型决定了反馈的名称。当对刺激措施的反应减少了最初的刺激措施时,就会出现负面反馈。当对刺激措施的反应增加了原先的刺激措施时,就会出现积极反馈。Positive feedback speeds up the direction of change, leading to increasing hormone concentrations, usually causing a state that moves further away from homeostasis. Positive feedback is therefore rare in biological systems. Nonetheless, it is present. A mammalian example of positive feedback is lactation (milk production). As the baby suckles, nerve messages from the mammary glands cause the hormone prolactin to be secreted by the pituitary gland . The more the baby suckles, the more prolactin is released, which stimulates further milk production.
::积极的反馈加快了变化的方向,导致荷尔蒙浓度上升,通常导致一种远离顺势的状态。因此,在生物系统中,积极的反馈是罕见的。尽管如此,它还是存在。哺乳动物的积极反馈例子是哺乳动物(哺乳动物的生产 ) 。 哺乳动物的神经信息使荷尔蒙蛋白被下垂腺掩盖。 婴儿的吸食越多,蛋白素就越释放,这刺激了牛奶的进一步生产。Thermoregulation: A Negative Feedback Loop
::温度调节:负反馈循环Negative feedback loops are the most common feedback loops in biological systems. The system acts to reverse the direction of change. Since this tends to keep things constant, it allows the maintenance of homeostatic balance. One negative feedback loop is thermoregulation, the process by which an ideal body temperature is maintained. When body temperature rises, receptors in the skin sense the temperature change, and the hypothalamus triggers a command within the brain . This command causes a physical response - the skin secretes sweat, and near the skin surface dilate, which helps decrease body temperature. Other negative feedback loops include the regulation of the amount of carbon dioxide and glucose in the blood stream. Figure shows the process by which the body regulates blood glucose. Carbon dioxide is regulated by our rate; as the breathing rate increases, the amounts of oxygen inhaled and carbon dioxide exhaled also increase.
::负反馈环是生物系统中最常见的反馈环环。 系统可以扭转变化方向。 由于它倾向于保持事物的恒定, 它允许保持顺势平衡。 一个负反馈环是温度调节, 即保持理想体温的过程。 当身体温度上升, 皮肤感应器, 温度变化, 和下丘脑触发大脑内部的指令。 此命令会引发物理反应 - 皮肤分泌汗, 皮肤表面放大, 有助于降低体温。 其他负反馈环包括调节血液流中的二氧化碳和葡萄糖数量。 图显示身体调节血糖的过程。 二氧化碳受我们的速度控制; 随着呼吸率的提高, 氧气和二氧化碳的释放量也会增加 。Control of blood glucose levels is an example of negative feedback. Blood glucose concentration rises after a meal (the stimulus). The hormone insulin is released by the pancreas, and it speeds up the transport of glucose from the blood into selected tissues (the response). Blood glucose concentrations then decrease, which then decreases the original stimulus. The secretion of insulin into the blood is then decreased.
::对血糖浓度的控制是消极反馈的一个例子。血糖浓度在一顿饭后上升(刺激剂 ) 。 胰腺释放了激素胰岛素,加速了将血糖从血液中迁移到特定组织(反应 ) 。 血糖浓度随后下降, 从而降低了最初的刺激力。 然后,将胰岛素分泌到血液中。Summary
::摘要-
Homeostasis, in the form of feedback loops, is the manner in which the human body maintains consistency in temperature, chemical levels, etc. It is a changing, non-stagnant process.
::以反馈循环为形式的自闭症是人体在温度、化学水平等方面保持一致性的方式。 这是一个变化的、非停滞的过程。 -
Positive feedback loops, which are rare, continually increase a change, while negative feedback loops reverse changes.
::积极反馈回路很少见,但不断增加变化,而消极反馈回路则逆转变化。
Review
::回顾-
In your own words, describe the process of homeostasis.
::用你自己的话来说,描述一下自足的过程。 -
For each of the following feedback loops, determine if it is positive or negative:
-
Clotting: An enzyme is produced that forms the matrix of the blood clot, but also speeds up the production of that same enzyme.
::克隆:生产一种酶,构成血凝块的基质,但也加速生产同样的酶。 -
Oxygen levels: When the kidneys sense low oxygen levels in the blood, they send hormonal signals to bone marrow to make more red blood cells.
::氧水平:当肾脏感觉到血液中的低氧水平时,它们会向骨髓发出荷尔蒙信号,以产生更多的红细胞。 -
Childbirth: Stretching of the uterus triggers secretions of a contraction-stimulating hormone to speed up labor.
::生育: 子宫的伸展会引发 一种抑制刺激荷尔蒙的分泌 以加速劳动。 -
Temperature regulation: When blood temperature drops, signals are sent to contract the arteries near the skin and to begin shivering. These serve to keep blood in the core and to release heat energy.
::温度调节:当血液温度下降时,发出信号,将皮肤附近的动脉连接起来,并开始发抖。这些信号有助于将血液保存在核心,释放热能。 -
Glucose levels: When blood glucose levels fall, insulin secretion is inhibited and glucose synthesis is stimulated.
::葡萄糖水平:当血液葡萄糖水平下降时,抑制胰岛素分泌,刺激葡萄糖合成。
::对于以下每一回路,确定它是正的还是负的: 克隆: 生成了酶,形成血凝块的矩阵,但也加速了同一种酶的生产。 氧水平: 当肾脏感觉血液中的氧含量较低时,它们会向骨髓发出激素信号,以产生更多的红细胞。 分娩: 子宫拉伸会触发收缩刺激激素的分泌以加快劳动速度。 温度调节: 当血液温度下降时, 信号被发送到皮肤附近的动脉中, 并开始发抖。 这些信号有助于将血液保存在核心, 释放热能。 葡萄糖水平: 当血糖水平下降时, 胰岛素分泌素会受到抑制, 葡萄糖合成会受到刺激。 -
Clotting: An enzyme is produced that forms the matrix of the blood clot, but also speeds up the production of that same enzyme.
-
Homeostasis, in the form of feedback loops, is the manner in which the human body maintains consistency in temperature, chemical levels, etc. It is a changing, non-stagnant process.
