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Oestrous Cycle - Anatomy & Physiology (view source)
Revision as of 13:06, 10 September 2008
, 13:06, 10 September 2008→Cyclic Changes in the Vagina
=== Cyclic Changes in the Vagina ===
=== Cyclic Changes in the Vagina ===
The main variations are in the epithelial cells of the anterior vagina and in the secretory function of the cervical glands.
* Oestrus: Anterior vaginal epithelium becomes greatly thickened due to cell division and the growth of the tall, columnar, mucus-secreting superficial cells.
* Dioestrus: Cells of the cranial vaginal epithelium vary from flat to low columnar. Invasion of the vaginal mucosa by leucocytes is maximal 2-5 days after oestrus.
* Copious secretion of mucus by the cervix and anterior vagina begins 1-2 days before oestrus.
* Secretions diminish to the 4th day after oestrus.
* Mucus is transparent and flows readily.
* Variations in cervical mucus:
** During oestrus and for a few days after, crystals are disposed in a distinct aborisation pattern.
** For the remainder of the cycle this pattern is absent.
** This pattern, and the amount of cervical mucus depends on oestrogen concentration.
* Postoestrous vaginal mucus:
** Floccules of leucocytes
** Blood is frequently present
* Hyperaemia of vaginal and cervical mucosae is progressive during pro-oestrus and oestrus.
* At this time, the protrusion of the cervix into the cranial vagina is relaxed, so that 1-2 fingers can be inserted into the cervical os.
* During metoestrus, there is a rapid reduction in vascularity.
* From day 3-5 postoestrus:
** Mucosa of the cervix is pale and quiescent.
** The external os is constricted.
** Mucus becomes scanty, sticky and pale yellow/brown.
* There are also cyclical changes in the vaginal pH:
** pH falls from 7.0 to 6.72 one day before first signs of behavioural oestrus.
** At the start of oestrus, pH falls again to 6.54.
=== Cyclic Changes in the Uterus ===
=== Cyclic Changes in the Uterus ===