Cervix of animals
Cervix of animals is a thick walled sphincter like structures which separates vagina from the uterus. Connective tissue is the major component and Some smooth muscles also found in cervix.
Lumen of cervix is narrow and exhibits annular rings. these are very prominent in cow and ewe and form interlocking rings but less prominent in the mare. In the sow the annular rings are cork screw shaped.
Epithelial lining is present in cervix part of female reproductive system. these lining have Columnar cells and goblet cells that secrete mucus. Physical and chemical properties of the mucus change during different phases of the estrous cycle and Progesterone reduces it.
Functions of cervix
- Transport of sperm- Ejaculation into vagina near the cervix in most species, Sperm oriented towards cervix, Hydrolytic enzymes in the semen digest back bone protein in the cervical mucus and remove cross linkages of mucin, Channels for sperm passage appear
- Sperm reservoir- Large number of sperm lodged into cervical crypts, Released slowly later, Prevents inundation of uterus by sperm, Makes the sperm available at the site of fertilization for up to 24h after mating
- Sperm selection center, Several sperm lodged in cervical crypts never get released, Particularly those that are less motile, Thus cervix selects only vigorously motile sperm for transport to the site of fertilization
- Protection of upper reproductive tract, Cervical mucus becomes thick and viscous during the luteal phase and seals the URT, This seal persists till next estrus or parturition
- Helps in parturition- Gross biochemical changes increase the size of the cervix enormously to allow the passage of the calf.
Cervix of animals during pregnancy
During pregnancy a tightly viscid, non ferning thick and turbid mucus occludes, the cervical canal, acting as a effective barrier against sperm transport and invasion of bacteria in the lumen, thus preventing the uterine infections.
The only other time cervix is open before parturition, at this time the cervical plug liquefies and the cervix dilates to permit the expulsion of the fetus and the fetal membranes.