[Campbell Biology P.1082] Which of the following is a key difference between menstrual cycles... | Practice Question

Which of the following is a key difference between menstrual cycles and estrous cycles in female mammals?

  • A: In menstrual cycles, the endometrium is reabsorbed, while in estrous cycles, it is shed.
  • B: Sexual receptivity is confined to a specific period around ovulation in menstrual cycles, but occurs throughout in estrous cycles.
  • C: Menstrual cycles involve extensive fluid flow, whereas estrous cycles typically do not.
  • D: Only humans and some primates exhibit estrous cycles, while all other female mammals have menstrual cycles.

Explanation

The text states: 'In other mammals, both domesticated and wild, the uterus reabsorbs the endometrium in the absence of a pregnancy, and no extensive fluid flow occurs. For these animals, the cyclic changes in the uterus occur as part of an estrous cycle.' Conversely, menstruation is described as 'the menstrual flow phase' where 'uterine lining largely disintegrates, releasing blood that is shed'.