Difference between revisions of "Oestrous Cycle - Anatomy & Physiology"
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| − | {{ | + | {{toplink |
| − | == | + | |backcolour =EED2EE |
| + | |linkpage =Reproductive System - Anatomy & Physiology | ||
| + | |linktext =Reproductive System | ||
| + | |maplink = Reproductive System (Content Map) - Anatomy & Physiology | ||
| + | |pagetype =Anatomy | ||
| + | |sublink1=Reproductive System - Anatomy & Physiology#Female Reproductive Tract | ||
| + | |subtext1=FEMALE REPRODUCTIVE TRACT | ||
| + | }} | ||
| + | <br> | ||
| − | + | =Introduction= | |
| − | + | 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. | ||
| − | |||
* Marked increase in reproductive activity. | * Marked increase in reproductive activity. | ||
| − | + | * Follicular growth and regression of the corpus luteum of the previous cycle (in polyoestrous species). | |
| − | * Follicular growth and | ||
* Uterus enlarges slightly | * Uterus enlarges slightly | ||
| − | * | + | * Endometrium becomes congested and oedematous, glands show secretory activity. |
| − | * | + | * Vaginal mucous becomes hyperaemic. |
| − | ** Increase in cell numbers in the | + | ** Increase in cell numbers in the vaginal epithelium. |
** Superficial layers become cornified. | ** Superficial layers become cornified. | ||
| − | * The ''' | + | * The '''bitch''' shows external evidence: |
| − | ** | + | ** Vulval oedema |
** Hyperaemia | ** Hyperaemia | ||
** Sanguinous vulval discharge | ** Sanguinous vulval discharge | ||
| Line 27: | Line 36: | ||
=== Oestrus === | === Oestrus === | ||
| − | * The period where the female will accept the male for | + | * 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. | ||
| − | * | + | * Uterine, cervical and vaginal glands secrete increased amounts of mucus. |
| − | * Vaginal epithelium and | + | * 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 | + | ** 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 | + | * 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. | ||
| Line 42: | Line 51: | ||
* The phase after oestrus | * 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. | |
| − | * Granulosa cells of the | + | * Reduction in secretion from uterine, cervical and vaginal glands. |
| − | |||
| − | * Reduction in secretion from | ||
=== Dioestrus === | === Dioestrus === | ||
| − | + | * The corpus luteum is present on the ovary and secreting large amounts of progesterone. | |
| − | * The | ||
| − | |||
* Uterine glands undergo hyperplasia and hypertrophy. | * Uterine glands undergo hyperplasia and hypertrophy. | ||
| − | * | + | * Cervix becomes constricted |
* Secretions of the tract are scant and sticky. | * Secretions of the tract are scant and sticky. | ||
| − | * | + | * Vaginal mucosa becomes pale. |
| − | |||
=== Anoestrus === | === Anoestrus === | ||
| Line 63: | Line 67: | ||
* 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 is constricted |
* Vaginal Mucosa is pale | * Vaginal Mucosa is pale | ||
| Line 83: | Line 87: | ||
== Based on Vaginal Cytology == | == Based on Vaginal Cytology == | ||
| − | + | =Comparative Oestrous Cycles= | |
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| − | == | + | = Links = |
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| − | [[ | + | [[Oestrous_Cycle_-Pharmacological_Manipulation_of_Oestrous_Cycles_-_Anatomy_%26_Physiology|Pharmacological Manipulation of Oestrous Cycles]] |
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Revision as of 11:09, 10 September 2008
|
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
- 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
- Begins after ovulation
- Includes the development of corpora luta, which produce progesterone.
- Includes luteolysis, which is brought about by Prostaglandin F2α.