Chapter 40 (2)

  1. Faced with environmental fluctuations, animals manage their internal environment by either __ or __.
    • regulating
    • conforming
  2. An animal is said to be a __ for a particular environemtal varibale if it uses internal control mechanisms to regulate internal change in the face of external fluctuation.
  3. An animal is said to be a __ for a particular environmental variable if it allows its internal condition to conform to external changes in the variable.
  4. _ and __ represent extremes on a continuum. An aimal may regulate some internal conditions while allowing others to conform to the environment.
    regulating and conforming
  5. The steady body temperature of a river otter and the stable concentration of solutes in a freshwater bass are examples of __, which means "steady state", or internal balance. In achieving __, animals maintain a relatively constant internal environment even when the external environment changes significantly.
    o Like many animals, humans exhibit __ for a range of physical and chemical properties, like body temp or pH.
    homeostasis x3
  6. How does an animal achieve homeostasis?
    By maintaining a variable, like body temp or solute concentration, at or near a particular value, or set point.
  7. Fluctuations in the variable above or below the __ serve as the __. A receptor, or __, detects the stimulus and triggers a __, a physiological activity that helps return the variable to the __.
    • set point
    • stimulus
    • sensor
    • response
    • set point
  8. Homeostasis in animals relies largely on __, a response that reduces, or "damps" teh stimulus.
    e.g sweating
    negative feedback
  9. Homeostasis is a __, the interplay between external factors that tend to change the internal environment and internal control mechanisms that oppose such changes. __ reduces but doesn't eliminate changes in the internal environment. Additional fluctuation occurs if a variable has a __- an upper and lower limit- rather than a single __. Regardless of whether there is a __ or a normal range, __ is enhanced by mechanisms that reduce fluctuations, such as insulation in the case of temp and physiological buffers in the case of pH.
    • dynamic equilibrium
    • homeostasis
    • normal range
    • set point x2
    • homeostasis
  10. Although __ also occur in animals, these circuits do not usually contribute to __. Unlike __, __ triggers mechanisms that amplify rather than diminish the stimulus.
    • positive feedback loops
    • homeostasis
    • negative feedback
    • positive feedback
  11. The __ and normal ranges for __ can change under various circumstances. In fact, so-called __ in teh internal nvironment are essential to normal body functions. Some __ are associated with a particular stage in life, such as the radical shift in hormone balance that occurs during puberty. Other __ are __, such as the variation in hormone levels responsible for women's menstrual cycles. Over the short term, __ mechanisms maintain the __ in effect during a particular interval. Over the longer term, __ allows regulated change in teh set point and therefore in teh body's internal environment.
    • set points
    • homeostasis
    • regulated changes x3
    • cyclic
    • homeostatic
    • set point
    • homeostasis
  12. One way in which the normal range of homeostasis may change is through __, teh process by which an animal adjusts to changes in its external environment. __, a atemporary change during an animal's lifetime, should not be confused with __, a process of change in a population brought abou tby natural selection over many generations.
    • acclimatization x2
    • adaptations
Card Set
Chapter 40 (2)
AP Bio