Changes

== Overview ==

== Overview ==

* There is immediate retrograde loss at the entrance to the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]]/[[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|uterus]] with phagocytosis by leukocytes.

* There is immediate retrograde loss at the entrance to the [[Cervix - Anatomy & Physiology|cervix]]/[[Uterus - Anatomy & Physiology|uterus]] with phagocytosis by leukocytes.

* In the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]], sperm must travel through privileged pathways.  This serves to eliminate non-motile sprem and remove some abnormalities.

* In the [[Cervix - Anatomy & Physiology|cervix]], sperm must travel through privileged pathways.  This serves to eliminate non-motile sperm and remove some abnormalities.

* In the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|uterus]], capacitation is initiated with some phagocytosis occuring.

* In the [[Uterus - Anatomy & Physiology|uterus]], capacitation is initiated with some phagocytosis occuring.

* In the [[Female_Reproductive_Tract_-The_Oviduct_-_Anatomy_%26_Physiology|oviduct]], capacitation is completed and sperm show hyperactive motility.

* In the [[Oviduct - Anatomy & Physiology|oviduct]], capacitation is completed and sperm show hyperactive motility.

* Sperm attach to the cillia of the epithelium in the isthmus of the [[Female_Reproductive_Tract_-The_Oviduct_-_Anatomy_%26_Physiology|oviduct]] to form a functional reservoir.  Only thousands from the initial millions in the ejaculate form this store, as 5-98% may be eliminated by retrograde flow or phagocytosis in the early female tract.

* Sperm attach to the cillia of the epithelium in the isthmus of the [[Oviduct - Anatomy & Physiology|oviduct]] to form a functional reservoir.  Only thousands from the initial millions in the ejaculate form this store, as 5-98% may be eliminated by retrograde flow or phagocytosis in the early female tract.

* At the uterotubal junction, the acrosome reaction occurs and the spermatozoon penetrated the oocyte in fertilization with the formation of male and female pronuclei.

* At the uterotubal junction, the acrosome reaction occurs and the spermatozoon penetrates the oocyte in fertilization with the formation of male and female pronuclei.

== Capacitation==

== Capacitation==

* If semen is deposited in the cranial vagina, capacitation may begin as sperm ascend the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]].

* If semen is deposited in the cranial vagina, capacitation may begin as sperm ascend the [[Cervix - Anatomy & Physiology|cervix]].

* If semen is deposited in the caudal [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] (mare) or mid-[[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] (sow) and immediately enters the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|uterus]], capacitation is initiated in the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|uterus]] and completed in the isthmus of the [[Female_Reproductive_Tract_-The_Oviduct_-_Anatomy_%26_Physiology|oviduct]].

* If semen is deposited in the caudal [[Cervix - Anatomy & Physiology|cervix]] (mare) or mid-[[Cervix - Anatomy & Physiology|cervix]] (sow) and immediately enters the [[Uterus - Anatomy & Physiology|uterus]], capacitation is initiated in the [[Uterus - Anatomy & Physiology|uterus]] and completed in the isthmus of the [[Oviduct - Anatomy & Physiology|oviduct]].

* During capacitation, the plasma membrane of the sperm undergoes marked biochemical changes.

* During capacitation, the plasma membrane of the sperm undergoes marked biochemical changes.

* During mixing of sperm with seminal plasma, epididymal sperm become coated in seminal plasma proteins.  These are stripped by the female tract environment.  These proteins were the decapacitating agents that were rendering the sperm incapable of fertilization.

* During mixing of sperm with seminal plasma, epididymal sperm become coated in seminal plasma proteins.  These are stripped by the female tract environment.  These proteins were the decapacitating agents that were rendering the sperm incapable of fertilization.

== Privileged Pathways ==

== Privileged Pathways ==

* Sperm must travel through the highly convoluted [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]].

* Sperm must travel through the highly convoluted [[Cervix - Anatomy & Physiology|cervix]].

* During oestrus, the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] produces mucus.

* During oestrus, the [[Cervix - Anatomy & Physiology|cervix]] produces mucus.

** '''Sialomucin''': Low viscosity mucus produced by basal areas of cervical crypts.

** '''Sialomucin''': Low viscosity mucus produced by basal areas of cervical crypts.

** '''Sulfomucin''': More viscous mucus produced in apical portions of the cervical epithelium covering the tips of cervical folds.

** '''Sulfomucin''': More viscous mucus produced in apical portions of the cervical epithelium covering the tips of cervical folds.

* The difference in viscosity of the mucus creates two distinct environments within the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]].

* The difference in viscosity of the mucus creates two distinct environments within the [[Cervix - Anatomy & Physiology|cervix]].

* Sperm encountering sulfomucin are washed out of the tract.

* Sperm encountering sulfomucin are washed out of the tract.

* Sperm encountering sialomucin swim into it, creating 'privileged pathways' in deeper cervical crypts. Sperm then traverse the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] through these pathways.

* Sperm encountering sialomucin swim into it, creating 'privileged pathways' in deeper cervical crypts. Sperm then traverse the [[Cervix - Anatomy & Physiology|cervix]] through these pathways.

* Thus, the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] acts as a filter to immotile sperm because in order to survive; the sperm must actively swim into the 'privileged pathways'.

* Thus, the [[Cervix - Anatomy & Physiology|cervix]] acts as a filter to immotile sperm because in order to survive; the sperm must actively swim into the 'privileged pathways'.

== Hyperactivation ==

== Hyperactivation ==

* Sperm digest a small hole in the zona pellucida through which it can pass.  This small,regional dissolution leaves the zona predominantly intact.  Maintainence of the zona is important to prevent blastomeres in the early embryo from separating.

* Sperm digest a small hole in the zona pellucida through which it can pass.  This small,regional dissolution leaves the zona predominantly intact.  Maintainence of the zona is important to prevent blastomeres in the early embryo from separating.

* Mechanical force generated by the flagellar action of the tail is sufficient to then push sperm through the zona.

* Mechanical force generated by the flagellar action of the tail is sufficient to then push sperm through the zona.