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Female Reproductive Tract - Horse Anatomy (view source)
Revision as of 16:23, 26 November 2012
, 16:23, 26 November 2012→Cervix
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==Cervix==
==Cervix==
The cervix can be palpated transrectally and forms a sphincter controlling access to the uterus. The anatomy of the cervical canal is adapted to suit a particular pattern of reproduction, and its composition will alter under the influence of reproductive hormones. Not only does it respond to the fluctuation in oestrodiol during the [[Oestrous Cycle - Anatomy & Physiology|oestrous cycle]], but is responsive to prostaglandins and oxytocin in order to [[Cervical Softening - Anatomy & Physiology|'soften']] for parturition.
The mare has a simple cervix, with the most caudal part bulging into the vagina to form a distinct recess ('''vaginal fornix'''). It has a multiple folds, including many longitudal folds of mucosa that protrude into the '''vaginal fornix'''. The cervix has a low volume of mucous secretion compared with that of other species. In the mare, the cervix is [[Cervical Softening - Anatomy & Physiology|'soft']] during oestrus.
The cervix provides a physical barrier to the uterus, therefore preventing abortion due to infection, by isolating the foetus from the external environment; closure is via the mucosal folds. Cervical mucosa produces a mucous secretion which forms a mucous plug that helps close the cervical canal. This is easily expelled during [[Oestrus Behaviour - Anatomy & Physiology|oestrus]] and parturition. The cervix does not form a barrier to sperm transport in the mare. It assists with the storage and survival of sperm, by admitting sperm to the genital tract at a time when [[Fertilisation - Anatomy & Physiology|fertilisation]] is possible (around [[Ovulation - Anatomy & Physiology|ovulation]]). It produces a small amount of mucus for lubrication and to prevent microorganisms from entering the uterus.
===Histology===
The lumen of the cervix is lined by a '''simple columnar epithelium''' containing many mucus producing cells. Some cilia may be seen on these cells. The uterine cervix protrudes into the upper vagina and contains the '''endocervical canal''' that links the uterine cavity with the vagina. The endocervical canal is lined by a single layer of tall '''columnar mucus-secreting cells'''. Where the cervix is exposed to the vagina (the ectocervix), it is lined by thick '''stratified squamous epithelium'''. Cells of the ectocervix often have clear cytoplasm due to their high glycogen content. The junction between the vaginal and endocervical epithelium is abrupt, normally located at the '''external os'''. This is the point where the endocervical canal opens into the vagina. The main bulk of the cervix is composed of tough, collagenous tissue with relatively little smooth muscle. Under the '''squamocolumnar junction''', the '''cervical stroma''' is infiltrated with leukocytes which defend against microorganisms. It is the cervical stroma that is influenced by the ovarian hormones.
===Vascularisation===
'''Uterine artery''', a branch off the '''External Iliac artery ''' in the mare.
==Vagina and Vestibule==
==Vagina and Vestibule==