Difference between revisions of "Oestrous Cycle - Anatomy & Physiology"

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==Introduction==
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|linkpage =Reproductive System - Anatomy & Physiology
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|linktext =Reproductive System
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|maplink = Reproductive System (Content Map) - Anatomy & Physiology
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|pagetype =Anatomy
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|sublink1=Reproductive System - Anatomy & Physiology#Female Reproductive Tract
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|subtext1=FEMALE REPRODUCTIVE TRACT
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<br>
  
Ovarian cycles are from oestrus to oestrus.  Oestrus is the easily identifiable external marker. It should be noted that Oestrus is the noun and oestrous is the adjective.
+
=Introduction=
  
'''Classification of Oestrous Cycles ''' can be done based on '''vaginal cytology''' or '''secretory patterns of the ovary'''.
+
Ovarian cycles are from oestrus to oestrus.  Oestrus is the easily identifiable external marker.
  
==Based on Vaginal Cytology ==
+
 
 +
= Classification of Oestrous Cycles =
 +
 
 +
== Based on Vaginal Cytology ==
  
 
=== Pro-Oestrus ===
 
=== Pro-Oestrus ===
  
 
* The phase immediately preceding oestrus.
 
* The phase immediately preceding oestrus.
* Lasts 2-5 days, depending on the species.
 
 
* Marked increase in reproductive activity.
 
* Marked increase in reproductive activity.
* Endocrine transition from progesterone to oestrogen dominance under the influence of gonadotrophins LH and FSH.
+
* Follicular growth and regression of the corpus luteum of the previous cycle (in polyoestrous species).
* Follicular growth and [[Corpus Luteum Regression - Anatomy & Physiology|regression of the corpus luteum]] of the previous cycle (in polyoestrous species).
 
 
* Uterus enlarges slightly
 
* Uterus enlarges slightly
* [[Uterus - Anatomy & Physiology#Endometrium|Endometrium]] becomes congested and oedematous, glands show secretory activity.
+
* Endometrium becomes congested and oedematous, glands show secretory activity.
* [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|Vaginal]] mucous becomes hyperaemic.  
+
* Vaginal mucous becomes hyperaemic.  
** Increase in cell numbers in the [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|vaginal]] epithelium.
+
** Increase in cell numbers in the vaginal epithelium.
 
** Superficial layers become cornified.
 
** Superficial layers become cornified.
* The '''[[Oestrous Cycle - Anatomy & Physiology#Bitch|bitch]]''' shows external evidence:
+
* The '''bitch''' shows external evidence:
** [[Vagina and Vestibule - Anatomy & Physiology#Vulva|Vulval]] oedema
+
** Vulval oedema
 
** Hyperaemia
 
** Hyperaemia
 
** Sanguinous vulval discharge
 
** Sanguinous vulval discharge
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=== Oestrus ===
 
=== Oestrus ===
  
* The period where the female will accept the male for [[Copulatory Behaviour - Anatomy & Physiology|copulation]].
+
* The period where the female will accept the male for copulation.
 
* The onset and end of oestrus are the only stages of the oetrous cycle that can be accurately measured.  They are therefore used to determine cycle length.
 
* The onset and end of oestrus are the only stages of the oetrous cycle that can be accurately measured.  They are therefore used to determine cycle length.
 
* Female seeks out the male and 'stands' to be mounted.
 
* Female seeks out the male and 'stands' to be mounted.
* [[Uterus - Anatomy & Physiology#Histology|Uterine]], [[Cervix - Anatomy & Physiology#Histology|cervical]] and [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|vaginal glands]] secrete increased amounts of mucus.
+
* Uterine, cervical and vaginal glands secrete increased amounts of mucus.
* Vaginal epithelium and [[Uterus - Anatomy & Physiology#Endometrium|uterine endometrium]] becomes hyperaemic and congested.
+
* Vaginal epithelium and uterine endometrium becomes hyperaemic and congested.
* [[Cervix - Anatomy & Physiology|Cervix]] is relaxed
+
* Cervix is relaxed
* [[Ovulation - Anatomy & Physiology|Ovulation]] occurs during this phase in all domestic species except the cow.
+
* Ovulation occurs during this phase in all domestic species except the cow.
** The cow [[Ovulation - Anatomy & Physiology|ovulates]] ~12 hours after the end of oestrus.
+
** The cow ovulates ~12 hours after the end of oestrus.
* [[Ovulation - Anatomy & Physiology|Ovulation]] is spontaneous in all domestic species except the cat, rabbit and camelids.  In these species it is induced by the act of [[Copulatory Behaviour - Anatomy & Physiology|copulation]].
+
* Ovulation is spontaneous in all domestic species except the cat, rabbit and camelids.  In these species it is induced by the act of copulation.
* During pro-oestrous and oestrus there is [[Ovary - Anatomy & Physiology#Folliculogenesis|follicular growth]] with no functional [[Corpus Luteum - Anatomy & Physiology|corpora lutea]] present on the [[Ovary - Anatomy & Physiology|ovary]] (aka follicular phase).
+
* During pro-oestrous and oestrus there is follicular growth with no functional corpora lutea present on the ovary (aka follicular phase).
 
* The main ovarian hormone production is Oestrogen.
 
* The main ovarian hormone production is Oestrogen.
  
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* The phase after oestrus
 
* The phase after oestrus
* During early metoestrus, both oestrogen and progesterone levels are relatively low.
+
* Granulosa cells of the ovulated follicle give rise to lutein cells, which are responsible for the formation of the corpus luteum.
* Granulosa cells of the [[Ovulation - Anatomy & Physiology|ovulated]] [[Follicles - Anatomy & Physiology|follicles]] give rise to lutein cells, which are responsible for the [[Corpus Luteum Formation - Anatomy & Physiology|formation of the corpus luteum]] (luteinisation).
+
* Reduction in secretion from uterine, cervical and vaginal glands.
* Progesterone secretion is detectable soon after [[Ovulation - Anatomy & Physiology|ovulation]], with significant quantities produced in 2-5 days.  This marks a transition from oestrogen to progesterone dominance.
 
* Reduction in secretion from [[Uterus - Anatomy & Physiology#Histology|uterine]], [[Cervix - Anatomy & Physiology#Histology|cervical]] and [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|vaginal glands]].
 
  
 
=== Dioestrus ===
 
=== Dioestrus ===
  
* Longest phase of the oestrous cycle, which usually laste 10-14 days in polyoestrous females. 
+
* The corpus luteum is present on the ovary and secreting large amounts of progesterone.
* The [[Corpus Luteum - Anatomy & Physiology|corpus luteum]] is present on the [[Ovary - Anatomy & Physiology|ovary]] and secreting large amounts of progesterone. The duration of this phase is directly related to the time that the corpus luteum remains functional.
 
* High progesterone levels prompt the uterus to prepare a suitable environment for development of the embryo, and eventual [[Implantation - Anatomy & Physiology|attachment of the conceptus to the endometrium]] (implantation).
 
 
* Uterine glands undergo hyperplasia and hypertrophy.
 
* Uterine glands undergo hyperplasia and hypertrophy.
* [[Cervix - Anatomy & Physiology|Cervix]] becomes constricted
+
* Cervix becomes constricted
 
* Secretions of the tract are scant and sticky.
 
* Secretions of the tract are scant and sticky.
* [[Vagina and Vestibule - Anatomy & Physiology#Vagina_2|Vaginal mucosa]] becomes pale.
+
* Vaginal mucosa becomes pale.
* Ends with the [[Corpus Luteum Regression - Anatomy & Physiology|regression of the corpus luteum]] (luteolysis).
 
  
 
=== Anoestrus ===
 
=== Anoestrus ===
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* Follicular development is minimal and corpora lutea have regressed and are non-functional.
 
* Follicular development is minimal and corpora lutea have regressed and are non-functional.
 
* Secretions are scanty
 
* Secretions are scanty
* [[Cervix - Anatomy & Physiology|Cervix]] is constricted
+
* Cervix is constricted
 
* Vaginal Mucosa is pale
 
* Vaginal Mucosa is pale
  
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=== Follicular Phase ===
 
=== Follicular Phase ===
 
* Begins after luteolysis, which causes the decline in progesterone.
 
* Gonadotrophins LH and FSH are produced, which cause ovarian follicles to produce Oestrogen.
 
* Ends at ovulation.
 
* Oestrus is designated as day 0.
 
  
 
=== Luteal Phase ===
 
=== Luteal Phase ===
  
* Begins after ovulation
+
=Comparative Oestrous Cycles=
* Includes the development of corpora luta, which produce progesterone.
 
* Includes luteolysis, which is brought about by Prostaglandin F2α.
 
 
 
== Based on Vaginal Cytology ==
 
 
 
=== Proliferative Phase ===
 
 
 
* Oestrogen dominant
 
* Includes proliferation of the [[Uterus - Anatomy & Physiology#Endometrium|endometrium]].
 
 
 
=== Secretory Phase ===
 
 
 
* Progesterone dominant
 
* Includes secretions from the uterus, such as 'uterine milk' to sustain the fertilised ovum until implantaion.
 
 
 
==Comparative Oestrous Cycles==
 
 
 
{| style="width:75%; height:200px" border="1"
 
 
 
!'''Species'''
 
!'''Mare'''
 
!'''Cow'''
 
!'''Sow'''
 
!'''Ewe'''
 
!'''Bitch'''
 
!'''Queen'''
 
|-
 
| '''Length of Oestrous Cycle (days)'''
 
| 21
 
| 21
 
| 21
 
| 17
 
| 93
 
| Variable
 
|-
 
| '''Duration of Oestrus'''
 
| 4-8 days
 
| 12-36 hours
 
| 48-96 hours
 
| 24-48 hours
 
| 7-13 days
 
| 4-10 days
 
|-
 
| '''Duration of Follicular Phase (days)'''
 
| 7 (variable)
 
| 4
 
| 7
 
| 3
 
| 18
 
| Variable
 
|-
 
| '''Duration of Luteal Phase (days)'''
 
| 14
 
| 17
 
| 14
 
| 14
 
| 75
 
| 40
 
|
 
|}
 
 
 
<big><b>
 
Oestrus Cycles in:
 
:[[Oestrous Cycle - Horse|Mare]]
 
:[[Oestrous Cycle - Dog|Bitch]]
 
:[[Oestrous Cycle - Cat|Queen]]
 
:[[Oestrous Cycle - Cattle|Cow]]
 
:[[Oestrous Cycle - Sheep|Ewe]]
 
:[[Oestrous Cycle - Goat|Nanny Goat]]
 
:[[Oestrous Cycle - Pig|Sow]]
 
 
 
</b></big>
 
 
 
== Links ==
 
 
 
* [[Oestrous Cycle Pharmacological Manipulation - Anatomy & Physiology|Pharmacological Manipulation of Oestrous Cycles]]
 
* [[Oestrus Behaviour - Anatomy & Physiology| Oestrus Behaviour and Methods of Oestrus Detection]]
 
 
 
  
==Webinars==
+
= Links =
<rss max="10" highlight="none">https://www.thewebinarvet.com/urogenital-and-reproduction/webinars/feed</rss>
 
  
[[Category:Oestrous Cycles]]
+
[[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]
[[Category:Bullet Points]]
 

Revision as of 11:00, 10 September 2008

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FEMALE REPRODUCTIVE TRACT



Introduction

Ovarian cycles are from oestrus to oestrus. Oestrus is the easily identifiable external marker.


Classification of Oestrous Cycles

Based on Vaginal Cytology

Pro-Oestrus

  • The phase immediately preceding oestrus.
  • Marked increase in reproductive activity.
  • Follicular growth and regression of the corpus luteum of the previous cycle (in polyoestrous species).
  • Uterus enlarges slightly
  • Endometrium becomes congested and oedematous, glands show secretory activity.
  • Vaginal mucous becomes hyperaemic.
    • Increase in cell numbers in the vaginal epithelium.
    • Superficial layers become cornified.
  • The bitch shows external evidence:
    • Vulval oedema
    • Hyperaemia
    • Sanguinous vulval discharge

Oestrus

  • The period where the female will accept the male for copulation.
  • The onset and end of oestrus are the only stages of the oetrous cycle that can be accurately measured. They are therefore used to determine cycle length.
  • Female seeks out the male and 'stands' to be mounted.
  • Uterine, cervical and vaginal glands secrete increased amounts of mucus.
  • Vaginal epithelium and uterine endometrium becomes hyperaemic and congested.
  • Cervix is relaxed
  • Ovulation occurs during this phase in all domestic species except the cow.
    • The cow ovulates ~12 hours after the end of oestrus.
  • Ovulation is spontaneous in all domestic species except the cat, rabbit and camelids. In these species it is induced by the act of copulation.
  • During pro-oestrous and oestrus there is follicular growth with no functional corpora lutea present on the ovary (aka follicular phase).
  • The main ovarian hormone production is Oestrogen.

Metoestrus

  • The phase after oestrus
  • Granulosa cells of the ovulated follicle give rise to lutein cells, which are responsible for the formation of the corpus luteum.
  • Reduction in secretion from uterine, cervical and vaginal glands.

Dioestrus

  • The corpus luteum is present on the ovary and secreting large amounts of progesterone.
  • Uterine glands undergo hyperplasia and hypertrophy.
  • Cervix becomes constricted
  • Secretions of the tract are scant and sticky.
  • Vaginal mucosa becomes pale.

Anoestrus

  • Genital system is quiescent
  • Follicular development is minimal and corpora lutea have regressed and are non-functional.
  • Secretions are scanty
  • Cervix is constricted
  • Vaginal Mucosa is pale

Based on Secretory Patterns of the Ovary

Follicular Phase

Luteal Phase

Comparative Oestrous Cycles

Links

Pharmacological Manipulation of Oestrous Cycles