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Oestrous Cycle - Anatomy & Physiology (view source)
Revision as of 15:21, 29 November 2010
, 15:21, 29 November 2010Text replace - "-_Anatomy_%26_Physiology" to "- Anatomy & Physiology"
* 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.
* Endocrine transition from progesterone to oestrogen dominance under the influence of gonadotrophins LH and FSH.
* Follicular growth and [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Corpus_Luteum_Regression|regression of the corpus luteum]] of the previous cycle (in polyoestrous species).
* Follicular growth and [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology#Corpus_Luteum_Regression|regression of the corpus luteum]] of the previous cycle (in polyoestrous species).
* Uterus enlarges slightly
* Uterus enlarges slightly
* [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|Endometrium]] becomes congested and oedematous, glands show secretory activity.
* [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|Endometrium]] becomes congested and oedematous, glands show secretory activity.
* [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vagina_2|Vaginal]] mucous becomes hyperaemic.
* [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vagina_2|Vaginal]] mucous becomes hyperaemic.
** Increase in cell numbers in the [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vagina_2|vaginal]] epithelium.
** Increase in cell numbers in the [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vagina_2|vaginal]] epithelium.
** Superficial layers become cornified.
** Superficial layers become cornified.
* The '''[[Female_Reproductive_Tract_-Oestrous_Cycle_-_Anatomy_%26_Physiology#Bitch|bitch]]''' shows external evidence:
* The '''[[Female_Reproductive_Tract_-Oestrous_Cycle_- Anatomy & Physiology#Bitch|bitch]]''' shows external evidence:
** [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vulva|Vulval]] oedema
** [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vulva|Vulval]] oedema
** Hyperaemia
** Hyperaemia
** Sanguinous [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vulva|vulval]] discharge
** Sanguinous [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vulva|vulval]] discharge
=== Oestrus ===
=== Oestrus ===
* The period where the female will accept the male for [[Reproductive_Behaviour_-_Copulatory_Behaviour_-_Anatomy_%26_Physiology|copulation]].
* The period where the female will accept the male for [[Reproductive_Behaviour_-_Copulatory_Behaviour_- Anatomy & Physiology|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.
* [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Histology|Uterine]], [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology#Histology|cervical]] and [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vagina_2|vaginal glands]] secrete increased amounts of mucus.
* [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Histology|Uterine]], [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology#Histology|cervical]] and [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vagina_2|vaginal glands]] secrete increased amounts of mucus.
* Vaginal epithelium and [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|uterine endometrium]] becomes hyperaemic and congested.
* Vaginal epithelium and [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|uterine endometrium]] becomes hyperaemic and congested.
* [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|Cervix]] is relaxed
* [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology|Cervix]] is relaxed
* [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|Ovulation]] occurs during this phase in all domestic species except the cow.
* [[The_Ovary_-_Ovulation_- Anatomy & Physiology|Ovulation]] occurs during this phase in all domestic species except the cow.
** The cow [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|ovulates]] ~12 hours after the end of oestrus.
** The cow [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulates]] ~12 hours after the end of oestrus.
* [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|Ovulation]] is spontaneous in all domestic species except the cat, rabbit and camelids. In these species it is induced by the act of [[Reproductive_Behaviour_-_Copulatory_Behaviour_-_Anatomy_%26_Physiology|copulation]].
* [[The_Ovary_-_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 [[Reproductive_Behaviour_-_Copulatory_Behaviour_- Anatomy & Physiology|copulation]].
* During pro-oestrous and oestrus there is [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Folliculogenesis|follicular growth]] with no functional [[Corpus Luteum - Anatomy & Physiology|corpora lutea]] present on the [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology|ovary]] (aka follicular phase).
* During pro-oestrous and oestrus there is [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology#Folliculogenesis|follicular growth]] with no functional [[Corpus Luteum - Anatomy & Physiology|corpora lutea]] present on the [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology|ovary]] (aka follicular phase).
* The main ovarian hormone production is Oestrogen.
* The main ovarian hormone production is Oestrogen.
* The phase after oestrus
* The phase after oestrus
* During early metoestrus, both oestrogen and progesterone levels are relatively low.
* During early metoestrus, both oestrogen and progesterone levels are relatively low.
* Granulosa cells of the [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|ovulated]] [[The_Ovary_-_Follicles_-_Anatomy_%26_Physiology|follicles]] give rise to lutein cells, which are responsible for the [[Corpus Luteum Formation - Anatomy & Physiology|formation of the corpus luteum]] (luteinisation).
* Granulosa cells of the [[The_Ovary_-_Ovulation_- Anatomy & Physiology|ovulated]] [[The_Ovary_-_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).
* Progesterone secretion is detectable soon after [[The_Ovary_-_Ovulation_-_Anatomy_%26_Physiology|ovulation]], with significant quantities produced in 2-5 days. This marks a transition from oestrogen to progesterone dominance.
* Progesterone secretion is detectable soon after [[The_Ovary_-_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 [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Histology|uterine]], [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology#Histology|cervical]] and [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vagina_2|vaginal glands]].
* Reduction in secretion from [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Histology|uterine]], [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology#Histology|cervical]] and [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vagina_2|vaginal glands]].
=== Dioestrus ===
=== Dioestrus ===
* Longest phase of the oestrous cycle, which usually laste 10-14 days in polyoestrous females.
* Longest phase of the oestrous cycle, which usually laste 10-14 days in polyoestrous females.
* The [[The_Ovary_-_Corpus_Luteum_-_Anatomy_%26_Physiology|corpus luteum]] is present on the [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology|ovary]] and secreting large amounts of progesterone. The duration of this phase is directly related to the time that the [[The_Ovary_-_Corpus_Luteum_-_Anatomy_%26_Physiology|corpus luteum]] remains functional.
* The [[The_Ovary_-_Corpus_Luteum_- Anatomy & Physiology|corpus luteum]] is present on the [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology|ovary]] and secreting large amounts of progesterone. The duration of this phase is directly related to the time that the [[The_Ovary_-_Corpus_Luteum_- Anatomy & Physiology|corpus luteum]] remains functional.
* High progesterone levels prompt the uterus to prepare a suitable environment for development of the embryo, and eventual [[Fertilisation%2C_Implantation_and_Early_Embryonic_Development_-Implantation-_Anatomy_%26_Physiology|attachment of the conceptus to the endometrium]] (implantation).
* High progesterone levels prompt the uterus to prepare a suitable environment for development of the embryo, and eventual [[Fertilisation%2C_Implantation_and_Early_Embryonic_Development_-Implantation- Anatomy & Physiology|attachment of the conceptus to the endometrium]] (implantation).
* Uterine glands undergo hyperplasia and hypertrophy.
* Uterine glands undergo hyperplasia and hypertrophy.
* [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|Cervix]] becomes constricted
* [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology|Cervix]] becomes constricted
* Secretions of the tract are scant and sticky.
* Secretions of the tract are scant and sticky.
* [[Female_Reproductive_Tract_-The_Vagina/Vestibule_-_Anatomy_%26_Physiology#Vagina_2|Vaginal mucosa]] becomes pale.
* [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology#Vagina_2|Vaginal mucosa]] becomes pale.
* Ends with the [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Corpus_Luteum_Regression|regression of the corpus luteum]] (luteolysis).
* Ends with the [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology#Corpus_Luteum_Regression|regression of the corpus luteum]] (luteolysis).
=== Anoestrus ===
=== Anoestrus ===
* 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
* [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|Cervix]] is constricted
* [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology|Cervix]] is constricted
* Vaginal Mucosa is pale
* Vaginal Mucosa is pale
* Oestrogen dominant
* Oestrogen dominant
* Includes proliferation of the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|endometrium]].
* Includes proliferation of the [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|endometrium]].
=== Secretory Phase ===
=== Secretory Phase ===
* The corpus luteum reaches full size at 4-5 days after ovulation but does not protrude from the ovarian surface.
* The corpus luteum reaches full size at 4-5 days after ovulation but does not protrude from the ovarian surface.
* On section of the ovary, the corpus luteum will appear brown and later yellow. It is triangular or conical in shape, with the narrow end on the ovulaiton fossa. The centre of the corpus luteum normally contains dark brown fibrin.
* On section of the ovary, the corpus luteum will appear brown and later yellow. It is triangular or conical in shape, with the narrow end on the ovulaiton fossa. The centre of the corpus luteum normally contains dark brown fibrin.
* The corpus luteum of the cycle (non-pregnant) starts to regress on about the 12th day of the cycle. At the time of [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Corpus_Luteum_Regression|regression]], there is a fall in blood progesterone concentration.
* The corpus luteum of the cycle (non-pregnant) starts to regress on about the 12th day of the cycle. At the time of [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology#Corpus_Luteum_Regression|regression]], there is a fall in blood progesterone concentration.
* Oestrus:
* Oestrus:
** Uterus is congested
** Uterus is congested
** [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|Endometrium]] contains oedematous fluid, which causes its surface to glisten.
** [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|Endometrium]] contains oedematous fluid, which causes its surface to glisten.
** Muscularis is contractile, so when palpated per rectum, the uterus feels turgid and the horns feel erect and coiled.
** Muscularis is contractile, so when palpated per rectum, the uterus feels turgid and the horns feel erect and coiled.
*** Tonicity is present the day before and the day after oestrus, but is at its maximum during heat.
*** Tonicity is present the day before and the day after oestrus, but is at its maximum during heat.
*** In heifers, there is also often perimetral subserous petechiae.
*** In heifers, there is also often perimetral subserous petechiae.
* Dioestrus:
* Dioestrus:
** [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|Endometrium]] is covered with scanty secretion from the uterine glands.
** [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|Endometrium]] is covered with scanty secretion from the uterine glands.
=== Cyclic Changes in the Ovaries ===
=== Cyclic Changes in the Ovaries ===
* As it ages, its colour goes from red to scarlet.
* As it ages, its colour goes from red to scarlet.
* Small remnants can persist for several months.
* Small remnants can persist for several months.
* For more general information on regression of the corpus luteum, click [[Female_Reproductive_Tract_-The_Ovary_-_Anatomy_%26_Physiology#Corpus_Luteum_Regression|here]]
* For more general information on regression of the corpus luteum, click [[Female_Reproductive_Tract_-The_Ovary_- Anatomy & Physiology#Corpus_Luteum_Regression|here]]
==== Size of Ovaries ====
==== Size of Ovaries ====
=== Cyclic Changes in the Uterus ===
=== Cyclic Changes in the Uterus ===
* The [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|endometrium]] shows considerable change during the oestrous cycle.
* The [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|endometrium]] shows considerable change during the oestrous cycle.
* In pro-oestrus and oestrus, endometrial glands are loosely coiled with obvious lumina and a deep epithelial lining.
* In pro-oestrus and oestrus, endometrial glands are loosely coiled with obvious lumina and a deep epithelial lining.
* During metoestrus, the glands become larger. Lumina become smaller and the basal layer of the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|endometrium]] becomes more tortuous.
* During metoestrus, the glands become larger. Lumina become smaller and the basal layer of the [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|endometrium]] becomes more tortuous.
* As the bitch reaches anoestrus, there is a reduction in the number of glands and the amount that they coil.
* As the bitch reaches anoestrus, there is a reduction in the number of glands and the amount that they coil.
* In metoestrus (~98 days after the onset of oestrus), there is desquamation of the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|endometrial]] epithelium.
* In metoestrus (~98 days after the onset of oestrus), there is desquamation of the [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|endometrial]] epithelium.
* By day 120-130, the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology#Endometrium|endometrium]] is restored by proliferation of cells from crypts of the endometrial glands.
* By day 120-130, the [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology#Endometrium|endometrium]] is restored by proliferation of cells from crypts of the endometrial glands.
=== Cyclic Changes in the Ovaries ===
=== Cyclic Changes in the Ovaries ===
=== Mating and Ovulation ===
=== Mating and Ovulation ===
* The queen is an induced ovulator, so [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_-_Anatomy_%26_Physiology|mating]] is important in triggering ovulation.
* The queen is an induced ovulator, so [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_- Anatomy & Physiology|mating]] is important in triggering ovulation.
* There are receptors in the vulva, which are stimualated by [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_-_Anatomy_%26_Physiology|copulation]].
* There are receptors in the vulva, which are stimualated by [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_- Anatomy & Physiology|copulation]].
* This results in release of LH fromt he anterior pituitary gland.
* This results in release of LH fromt he anterior pituitary gland.
* Only 50% of queens ovulate after a single [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_-_Anatomy_%26_Physiology|mating]], because multiple ovulations are usually required for adequate LH release.
* Only 50% of queens ovulate after a single [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_- Anatomy & Physiology|mating]], because multiple ovulations are usually required for adequate LH release.
* The ovulatory LH surge begins within minutes of coitus.
* The ovulatory LH surge begins within minutes of coitus.
* LH peaks within 2 hours, then returns to basal levels within 8 hours.
* LH peaks within 2 hours, then returns to basal levels within 8 hours.
* Further [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_-_Anatomy_%26_Physiology|matings]] before the peak in LH will result in further LH release.
* Further [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_- Anatomy & Physiology|matings]] before the peak in LH will result in further LH release.
* After [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_-_Anatomy_%26_Physiology|multiple matings]] over 4 hours or more, further matings will not result in any further LH release.
* After [[Reproductive_Behaviour_-_Copulatory_Behaviour_Cat_- Anatomy & Physiology|multiple matings]] over 4 hours or more, further matings will not result in any further LH release.
** Due to depletion of the pituitary pool of LH, or the pituitary becoming refractory to further GnRH stimulation.
** Due to depletion of the pituitary pool of LH, or the pituitary becoming refractory to further GnRH stimulation.
* Once significant quantities of LH are reached, all ripe follicles will rupture (all or nothing response).
* Once significant quantities of LH are reached, all ripe follicles will rupture (all or nothing response).
= Links =
= Links =
* [[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]]
* [[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_- Anatomy & Physiology|Pharmacological Manipulation of Oestrous Cycles]]
* [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology| Oestrus Behaviour and Methods of Oestrus Detection]]
* [[Reproductive_Behaviour_-_Oestrus_Behaviour_- Anatomy & Physiology| Oestrus Behaviour and Methods of Oestrus Detection]]