Changes

* Sperm in the female tract reach the isthmus of the oviduct and bind to the mucosal epithelial cells, forming a functional reservoir.

* Sperm in the female tract reach the isthmus of the oviduct and bind to the mucosal epithelial cells, forming a functional reservoir.

*  The sperm are only released from the isthmus mucosa by the action of paracrine signals from an ova travelling down the oviduct.

*  The sperm are only released from the isthmus mucosa by the action of paracrine signals from an ova travelling down the oviduct.

** The formation of a functional reservoir is a possible supporting mechanism of [[Fertilisation, Implantation and Early Embryonic Development -Fertilisation- Anatomy & Physiology|Block to polyspermy]], as only a few sperm are released from the isthmus mucosa at any one time. This results in only a few sperm being in the vicinity of the ova at a time and so in a position of fertilising the ova.

** The formation of a functional reservoir is a possible supporting mechanism of [[Fertilisation - Anatomy & Physiology|Block to polyspermy]], as only a few sperm are released from the isthmus mucosa at any one time. This results in only a few sperm being in the vicinity of the ova at a time and so in a position of fertilising the ova.

* The oviducts open into the uterine horn through the uterine ostium.

* The oviducts open into the uterine horn through the uterine ostium.