Discussions of how hormones influence behavior have generally been limited to the effects of gonadal hormones on reproductive behavior and have emphasized the parsimonious arrangement whereby the same hormones involved in the biology of reproduction also influence sexual behavior. It has now become clear, however, that other hormones, in addition to their recognized influence on biological functions, can affect behavior. Specifically, peptide and steroid hormones involved in maintaining the physiological balance, or homeostasis, of body fluids also appear to play an important role in the control of water and salt consumption. The phenomenon of homeostasis in animals depends on various mechanisms that promote stability within the organism despite an inconstant external environment; the homeostasis of body fluids, whereby the osmolality (the concentration of solutes) of blood plasma is closely regulated, is achieved primarily through alterations in the intake and excretion of water and sodium, the two principal components of the fluid matrix that surrounds body cells. Appropriate compensatory responses are initiated when deviations from normal are quite small, thereby maintaining plasma osmolality within relatively narrow ranges.
In the osmoregulation of body fluids, the movement of water across cell membranes permits minor fluctuations in the concentration of solutes in extracellular fluid to be buffered by corresponding changes in the relatively larger volume of cellular water. Nevertheless, the concentration of solutes in extracellular fluid may at times become elevated or reduced by more than the allowed tolerances of one or two percent. It is then that complementary physiological and behavioral responses come into play to restore plasma osmolality to normal. Thus, for example, a decrease in plasma osmolality, such as that which occurs after the consumption of water in excess of need, leads to the excretion of surplus body water in the urine by inhibiting secretion from the pituitary gland of vasopressin, a peptide hormone that promotes water conservation in the kidneys. As might be expected, thirst also is inhibited then, to prevent further dilution of body fluids. Conversely, an increase in plasma osmolality, such as that which occurs after one eats salty foods or after body water evaporates without being replaced, stimulates the release of vasopressin, increasing the conservation of water and the excretion of solutes in urine. This process is accompanied by increased thirst, with the result of making plasma osmolality more dilute through the consumption of water. The threshold for thirst appears to be slightly higher than for vasopressin secretion, so that thirst is stimulated only after vasopressin has been released in amounts sufficient to produce maximal water retention by the kidneys—that is, only after osmotic dehydration exceeds the capacity of the animal to deal with it physiologically.
Which one of the following best states the main idea of
the passage?
(A) Both the solute concentration and the volume of
an animal's blood plasma must be kept within
relatively narrow ranges.
(B) Behavioral responses to changes in an animal's
blood plasma can compensate for physiological
malfunction, allowing the body to avoid
dehydration.
(C) The effect of hormones on animal behavior and
physiology has only recently been discovered.
(D) Behavioral and physiological responses to major
changes in osmolality of an animal's blood
plasma are hormonally influenced and
complement one another.
(E) The mechanisms regulating reproduction are
similar to those that regulate thirst and sodium
appetite.
想请张慧雯老师帮忙解答!
老师,这篇文章我觉得读不懂正常,读的懂才不正常。
虽然文章满篇的各种生物专业名词,各种什么生物现象的描述,但是如果只抓主旨,文章又变得很简单。因此想确认下自己读的是不是对的,因为自己选错了。
阅读过程:
第一段:
·对于荷尔蒙如何影响行为的讨论通常局限于g荷尔蒙对生殖行为的影响并且强调了一个p安排(看不懂,逻辑属于并列不用管)
·然而,(重点关注转折),现在这一点非常清楚:其他的荷尔蒙,除了这些荷尔蒙对其他生物功能的影响外,也会影响行为 就是现在了解到存在其他的荷尔蒙影响生物功能也影响行为
·后面specifically,太明显的细化逻辑词汇,我尝试读了下:参与到维持生理平衡的p和s荷尔蒙似乎有什么重要的作用... 读到这我再次确认主旨就是在说荷尔蒙如何影响生理如何影响行为
·the phenomenon of h不用看了,全是细节 第一段完
第二段:
在身体液体的o里,水的流动允许什么 这个视角太细了。跳到第二句,然而,e液体的浓度升高。 OK不用看了,段间关系已经出来,第二段整体仍然属于第一段的细节,主旨仍然没有变化。 第二段后面通过扫读,什么po的下降,相反,po的上升,讲了一堆我看不懂的东西。 全是细节跳过
因此文章主旨就是最近很清楚的是:存在一些其他的荷尔蒙,除了影响生理功能外还会影响行为
最后选了C选项:荷尔蒙对动物行为和生理的影响最近被发现
答案是D:对动物血液p内O的主要变化做出的生理和行为反应都是受到荷尔蒙上的影响并且彼此弥补
因为D说了一些特别细的东西什么动物血液P+complement one another,我又根本没读明白文章,就将D排除了。
是否我在读主旨存在问题,少读了一些东西。