Estrous Cycle: Difference between revisions

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==Estrous Cycle Stages==
==Estrous Cycle Stages==
The descriptions below refer to the "typical" mammalian cycle.
:proestrus - estrus - metestrus - diestrus


proestrus - estrus - metestrus - diestrus
===Proestrus===
The first stage in the estrous cycle immediately before estrus characterized by development of both the endometrium and ovarian follicles.
 
===Estrus===
The second stage in the estrous cycle immediately before metestrus characterized by a receptivity to a male and to mating, often referred to as "heat" or "in heat". Pheromones may also be secreted only at this stage of her cycle.
 
===Metestrus===
The third stage in the estrous cycle immediately before diestrus characterized by sexual inactivity and the formation of the corpus luteum.
 
===Diestrus===
The last stage in the estrous cycle immediately before the next cycle proestrus characterized by a functional corpus luteum and an increase in the blood concentration of prosgesterone.


==Rat Estrous Cycle==
==Rat Estrous Cycle==

Revision as of 13:01, 25 April 2010

Mouse ovarian follicle size.jpg

Introduction

The estrous cycle (British spelling, oestrous) is the main reproductive cycle of other species females of non-primate vertebrates, for example rats, mice, horses, pig have this form of reproductive cycle. There are also a variety of different forms:

  • Polyestrous Animals - Estrous cycles throughout the year (cattle, pigs, mouse, rat).
  • Seasonally Polyestrous Animals - Animals that have multiple estrous cycles only during certain periods of the year (horses, sheep, goats, deer, cats).
  • Monestrous Animals - Animals that have one estrous cycle per year (dogs, wolves, foxes, and bear)

Links: Estrous Cycle | Mouse Estrous Cycle | original page

Estrous Cycle Stages

The descriptions below refer to the "typical" mammalian cycle.

proestrus - estrus - metestrus - diestrus

Proestrus

The first stage in the estrous cycle immediately before estrus characterized by development of both the endometrium and ovarian follicles.

Estrus

The second stage in the estrous cycle immediately before metestrus characterized by a receptivity to a male and to mating, often referred to as "heat" or "in heat". Pheromones may also be secreted only at this stage of her cycle.

Metestrus

The third stage in the estrous cycle immediately before diestrus characterized by sexual inactivity and the formation of the corpus luteum.

Diestrus

The last stage in the estrous cycle immediately before the next cycle proestrus characterized by a functional corpus luteum and an increase in the blood concentration of prosgesterone.

Rat Estrous Cycle

One of the best characterised reproductive cycles, though different species of rats may differ in reproduction. In general, puberty occurs at 6-8 weeks when the oestrous cycle commences each cycle is 4-5 days.

The estrous cycle is Polyoestrous with an estrous period of approximately 12 hours.

Links: Rat Development | PMID: 16195173 | PubMed- rat estrous cycle

Mouse Estrous Cycle

The mouse oestrus cycle is 4-6 days, with oestrus lasting less than 1 day. (More? Other Embryos- Mouse Estrous Cycle)

The estrus cycle stops during lactation except for one oestrus 12-20 hours postpartum.

Determining the stage of the estrous cycle in the mouse by the appearance of the vagina.[1]

  • Estrous Diestrus - Vagina has a small opening and the tissues are bluish-purple in color and very moist.
  • Proestrus - Vagina is gaping and the tissues are reddish-pink and moist. Numerous longitudinal folds or striations are visible on both the dorsal and ventral lips.
  • Estrus - Vaginal signs are similar to proestrus, but the tissues are lighter pink and less moist, and the striations are more pronounced.
  • Metestrus-1 - Vaginal tissues are pale and dry. Dorsal lip is not as edematous as in estrus.
  • Metestrus-2 - Vaginal signs are similar to metestrus-1, but the lip is less edematous and has receded. Whitish cellular debris may line the inner walls or partially fill the Vagina.

Links: Mouse Estrous Cycle

Pig Estrous Cycle

The feedback systems between the ovaries, uterus, hypothalamus and pituitary gland govern a cycle of events that takes 18-21 days. If conception occurs this cyclic pattern is interrupted and pregnancy is maintained for approximately 114 days. Removal of the sucking stimulus at weaning triggers a new sequence of events.

Links: Pig Development | PubMed- pig estrous cycle

References

  1. Determining the stage of the estrous cycle in the mouse by the appearance of the vagina. Champlin AK, Dorr DL, Gates AH. Biol Reprod. 1973 May;8(4):491-4. PMID: 4736343


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Cite this page: Hill, M.A. (2024, March 29) Embryology Estrous Cycle. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Estrous_Cycle

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