6.1 排泄系统
章节大纲
-
What do you do with your waste?
::你用你的废物做什么?Toxic waste must be disposed of properly, or there can be serious consequences. Now, your waste should not be as colorful or toxic as shown here (if it is, get yourself to a doctor as soon as possible), but it still needs to be removed from you. And that is the role of the excretory system. The excretory system gets rid of waste and excess .
::有毒废物必须妥善处理,否则会产生严重后果。 现在,您的废物不应该像这里所显示的那样多彩或有毒(如果是这样的话,尽快去看医生 ) , 但仍然需要从你身上移除。 这就是排泄系统的作用。 排泄系统可以清除废物和过剩。Homeostasis and Excretion
::常住和放行If you on a hot day, you are likely to lose a lot of water in sweat. Then, for the next several hours, you may notice that you do not pass urine as often as normal and that your urine is darker than usual. Do you know why this happens? Your body is low on water and trying to reduce the amount of water lost in urine. How does the body know when it is low on water? How does it control the amount of water lost in urine? The answers to both questions are the and the glands that control them.
::如果你在炎热的一天,你可能会在汗水中流失大量水。然后,在接下来的几个小时里,你可能会注意到你没有像平常那样频繁地通过尿液,你的尿液比平时更暗。你知道为什么会这样吗?你的身体缺水,试图减少尿液中缺水量。身体怎么知道水位低?它如何控制尿水流失量?这两个问题的答案都是控制尿水的腺和腺。The kidneys are the body’s main organs of and excretion . Homeostasis is the body’s attempt to maintain a constant internal environment. One of the major ways the body achieves homeostasis is through excretion. Excretion is the process of removing wastes and excess water from the body.
::肾脏是身体的主要器官和排泄物。 软骨是身体试图保持一个稳定的内部环境。 身体实现软骨的主要方法之一是通过排泄。 排泄物是从身体中清除废物和多余水的过程。Homeostasis
::常态Homeostasis is a fundamental characteristic of all living things. Internal body conditions must be kept within certain limits for the normal functioning of . Homeostasis involves keeping many internal factors at more or less constant levels. The factors include body temperature and properties of the . For example, the blood must have certain levels of acidity, salts, and nutrients in order for cells to function normally.
::自闭症是所有生物的基本特征之一,内部身体状况必须保持在一定的限度内,才能正常运转。自闭症涉及将许多内在因素保持在或多或少的不变水平上,这些因素包括身体温度和身体特性。例如,血液必须具有一定的酸度、盐类和营养素,以便细胞正常运转。A variety of homeostatic mechanisms help maintain stability of the internal environment. Each mechanism involves the interaction of at last three components: a receptor, a control center, and an effector.
::各种自成一体的机制有助于维持内部环境的稳定。 每种机制都涉及最后三个组成部分的相互作用:受体、控制中心和影响器。-
The receptor
changes in the internal environment and sends the information to the control center.
::内部环境的受体变化 并发送信息到控制中心。 -
The control center processes the information, determines the appropriate action, and sends a command to the effector.
::控制中心处理信息,确定适当的动作,并向效果器发送命令。 -
The effector responds to the command and changes conditions in the internal environment.
::效果器响应命令和内部环境的改变条件。
An example of a homeostatic mechanism in humans is the regulation of body temperature. This is represented by the diagram in Figure . Temperature receptors in the skin send information about skin temperature to the brain . The brain is the control center. It determines whether the temperature is too high or too low and sends appropriate commands to effectors that control body temperature. Effectors include near the surface of the body. If the temperature is too high, the brain commands the blood vessels to dilate, which helps the body lose heat. If the temperature is too low, the brain commands the blood vessels to constrict, which helps the body retain heat. These actions help return body temperature to normal.
::人体自温机制的一个例子是调节体温。图中的图表代表了这一点。皮肤中的温度受体向大脑传递皮肤温度的信息。大脑是控制中心。它决定温度是否太高或太低,并且向控制体温的施压器发出适当的指令。效应器包括身体表面附近。如果温度太高,大脑会命令血管进行扩张,从而帮助身体失去热量。如果温度太低,大脑会命令血管进行控制,帮助身体保持热量。这些行动有助于身体恢复正常的体温。Negative Feedback and Body Temperature
::负反馈和体温Regulation of body temperature is an example of negative feedback. When body temperature deviates from normal, this information feeds back to the brain and sets in motion changes that return body temperature to normal.
::调节体温是负面反馈的一个例子。 当体温偏离正常时,这些信息会反馈回大脑,并引发运动变化,使体温恢复正常。The regulation of body temperature is an example of negative feedback . Negative feedback is a type of homeostatic mechanism in which change in one direction results in a counteractive change in the opposite direction. Negative feedback reverses the direction of change to bring conditions back to normal. Most of the mechanisms that control homeostasis in the involve negative feedback.
::调节体温是消极反馈的一个例子。消极反馈是一种自制机制,在这种机制中,一个方向的改变导致相反方向的反向变化。消极反馈逆转了改变的方向,使情况恢复正常。大多数控制自制的机制都包含消极反馈。Positive feedback mechanisms also exist, but they are not common in the human body. Positive feedback accelerates or amplifies a change and pushes levels further away from normal. One example of a positive feedback mechanism in the body is blood clotting.
::积极的反馈机制也存在,但在人体中并不常见。 积极的反馈机制加速或放大了变化,将水平推离了正常。 积极反馈机制在人体中的一个例子就是血液凝结。If homeostasis is disturbed, a homeostatic imbalance results. This may result in cells getting too much or not enough of certain substances. Many diseases are caused by homeostatic imbalances. For example, mellitus is a disease in which the blood contains too much glucose . This can have serious consequences for cells throughout the body. It may lead to damaged blood vessels, heart disease, blindness, and kidney failure .
::如果内固醇紊乱,则会造成自闭症的不平衡,可能导致细胞过多或不够某些物质,许多疾病是自闭症不平衡造成的,例如,宫颈病是血液含有过多葡萄糖的疾病,可能对全身细胞产生严重后果,可能导致血管损伤、心脏病、失明和肾衰竭。Excretion
::自由裁量Excretion is an essential process in all forms of life. When cells metabolize—or break down nutrients—waste products are produced. For example, when cells metabolize and , nitrogen wastes, such as ammonia, urea, and uric acid, are produced. Ammonia is a toxic substance and must be removed from the blood and excreted from the body. Urea is removed through urine, which is produced in the kidneys. Excretion is also necessary to remove excess water, salts, and many other substances from the body.
::当细胞代谢——或分解营养素——产生废品时,会产生新陈代谢和氮废物,例如,产生新陈代谢和氮废物,例如氨、尿素和硫酸,氨是一种有毒物质,必须从血液中取出,从身体中排出,通过尿液清除尿液,尿液在肾脏中产生,排泄也是从身体中去除多余的水、盐类和许多其他物质所必须的。Although the kidneys are the main organs of waste excretion from the blood, several other organs are also involved in excretion, including the , liver , skin, and lungs .
::虽然肾是血液中废物排泄物的主要器官,但其他一些器官也参与排泄,包括肝脏、皮肤和肺部。-
The large intestine eliminates solid wastes that remain after the
digestion
of
food
in the
gastrointestinal tract
(as discussed in
Concept
17.60: The Large Intestine-Advanced
).
::大型肠道消除了在胃肠道食物消化后遗留下来的固体废物(见概念17.60:大型不孕动物。 -
The liver breaks down excess
amino acids
in the blood to form ammonia and then converts the ammonia to urea, a less toxic substance. The liver also breaks down other toxic substances in the blood, including alcohol and
drugs
.
::肝脏分解血液中多余的氨基酸,形成氨,然后将氨转化为尿素,一种毒性较低的物质,肝脏还分解血液中的其他有毒物质,包括酒精和毒品。 -
The skin eliminates water and salts in sweat.
::皮肤消除了汗水和盐类。 -
The lungs exhale water vapor and carbon dioxide.
::肺吸入水蒸气和二氧化碳
Summary
::摘要-
Homeostasis is the body’s attempt to maintain a constant internal environment.
::保持原状是身体试图维持一个稳定的内部环境。 -
One of the major ways the body achieves homeostasis is through excretion, the process of removing wastes and excess water from the body.
::身体实现顺势的主要方法之一是通过排泄,即从身体中清除废物和多余水的过程。 -
Most of the mechanisms that control homeostasis in the human body involve negative feedback.
::控制人体自闭力的大多数机制都包含负面反馈。 -
The kidneys are the body’s main organs of homeostasis and excretion, although the large intestine, liver, skin, and lungs are also involved.
::肾脏是身体的顺势保持和排泄的主要器官,尽管大肠、肝脏、皮肤和肺也是其中的一部分。
Review
::回顾-
What are the three components of any homeostatic mechanism? What are their roles?
::任何顺势机制的三个组成部分是什么?它们的作用是什么? -
What is the difference between negative feedback and positive feedback?
::消极反馈和积极反馈有什么区别? -
What is the role of the liver in the excretory system?
::肝脏在排泄系统中的作用是什么?
-
The receptor
changes in the internal environment and sends the information to the control center.