12.26 其他器官
章节大纲
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Is this bear cold?
::这是熊冷吗?Not really. Like all mammals , polar bears maintain a stable internal temperature. They do not need to stay warm by lying in the sun. This allows them to live in cold climates.
::不像所有哺乳动物一样,北极熊保持稳定的内温。它们不需要躺在太阳下而保持温暖。这样它们就可以生活在寒冷的气候中。Endothermy in Mammals
::哺乳动物的外科Many structures and functions in mammals are related to endothermy . Mammals can generate and conserve heat when it’s cold outside. They can also lose heat when they become overheated. How do mammals control their body temperature in these ways?
::哺乳动物的许多结构和功能都与外科有关。哺乳动物可以在外面寒冷时产生和保持热量。 当它们过热时,它们也会失去热量。 哺乳动物如何以这些方式控制它们的体温?How Mammals Stay Warm
::哺乳动物如何保持温暖Mammals generate heat mainly by keeping their metabolic rate high. The of mammals have many more than the cells of other . The extra mitochondria generate enough energy to keep the rate of metabolism high. Mammals can also generate little bursts of heat by shivering . Shivering occurs when many contract a little bit all at once. Each muscle that contracts produces a small amount of heat.
::哺乳动物主要通过保持代谢率高,产生热量。哺乳动物的细胞比其他动物的细胞多得多。外的米托昆氏菌产生足够的能量以保持新陈代谢率高。哺乳动物也可以通过颤动产生少量的热爆发。当许多哺乳动物同时略微收缩时,就会出现抖动。每个肌肉的结合产生少量的热量。Conserving heat is also important, especially in small mammals. A small body has a relatively large surface area compared to its overall size. Because heat is lost from the surface of the body, small mammals lose a greater proportion of their body heat than large mammals. Mammals conserve body heat with their hair or fur. It traps a layer of warm air next to the skin. Most mammals can make their hair stand up from the skin, so it becomes an even better insulator. Even humans automatically contract these muscles when they are cold, causing goosebumps (see Figure ). Mammals also have a layer of fat under the skin to help insulate the body. This fatty layer is not found in other vertebrates .
::保护热量也很重要,特别是在小型哺乳动物身上。一个小身体的表面面积比其总体大小相对较大。由于体表丧失热量,小哺乳动物的体热比大型哺乳动物减少更大比例。哺乳动物用毛发或毛保护体热量。它把一层温暖的空气困在皮肤旁边。大多数哺乳动物可以把头发从皮肤上拉起来,因此它会变得更好。即使人类在寒冷时也会自动结合这些肌肉,造成鹅跳(见图 ) 。哺乳动物的皮肤下也有一层脂肪来帮助使身体绝热。其他脊椎动物中也找不到这种脂肪层。Mammals raise their hair with tiny muscles in the skin. Even humans automatically contract these muscles when they are cold. They cause “goosebumps,” as shown here. How Mammals Stay Cool
::哺乳动物如何保持冷静One way mammals lose excess heat is by increasing flow to the skin. This warms the skin so heat can be given off to the environment. That’s why you may get flushed, or red in the face, when you on a hot day. You are likely to sweat as well. Sweating also reduces body heat. Sweat wets the skin, and when it evaporates, it cools the body. Evaporation uses energy, and the energy comes from body heat. Animals with fur, such as dogs, use panting instead of sweating to lose body heat (see Figure ). Evaporation of from the tongue and other moist surfaces of the mouth and throat uses heat and helps cool the body.
::哺乳动物减少超热的方法之一是增加皮肤的流量。这让皮肤变暖,这样可以把皮肤变暖,让环境变暖。这就是为什么在炎热的一天,你可能会被冲洗,或者脸部红红。你也可能出汗。湿润也会减少体温。湿润的皮肤会湿润皮肤,当皮肤蒸发时,它会冷却身体。蒸发利用能量,能量来自体温。毛毛动物,如狗,用气喘而不是流汗来失去体温(见图 ) 。 从舌头和其他湿润的口腔和喉咙表面蒸发,用热来帮助体温。Panting Dog. This dog is overheated. It is losing excess body heat by panting. Summary
::摘要-
Mammals have several ways of generating and conserving heat, such as a high metabolic rate and hair to trap heat.
::哺乳动物有几种产生和保存热量的方法,例如高代谢率和头发捕捉热量。 -
Mammals also have several ways to stay cool, including sweating or panting.
::哺乳动物还有几种保持冷静的方式,包括出汗或喘气。
Review
::回顾-
Describe how mammals stay warm and conserve heat?
::描述哺乳动物如何保持温暖和保持热量? -
What is the function of sweating? Explain your answer.
::出汗有什么作用? -
How do animals with fur lose excess heat?
::毛皮动物如何失去超热?
Resources
::资源 -
Mammals have several ways of generating and conserving heat, such as a high metabolic rate and hair to trap heat.
