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Normal Parturition - Anatomy & Physiology (view source)
Revision as of 09:11, 15 July 2008
, 09:11, 15 July 2008New page: * The Process by which the conceptus (foetus, placenta and placental membranes) are expelled from the Uterus requires: **...
* The Process by which the conceptus (foetus, placenta and placental membranes) are expelled from the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|Uterus]] requires:
** [[Parturition - Cervical Softening - Anatomy & Physiology|Cervical Softening]]
** [[Parturition - Coordinated Myometrial Contraction - Anatomy & Physiology|Coordinated Myometrial Contraction]]
** Voluntary contraction of abdominal muscles
* In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.
* Expulsion of the foetus requires that the chorionic villi become dislodged from the crypts of the maternal side of the [[Female_Reproductive_Tract_-Placenta_-_Anatomy_%26_Physiology|placenta]].
** Brought about by powerful vasoconstriction of arteries in the villi.
*** Vasoconstriction reduces pressure and allows villi to be released from crypts.
'''Normal Parturition'''
{| style="width:75%; height:200px" border="1"
!'''Species'''
!'''Mare'''
!'''Cow'''
!'''Ewe'''
!'''Sow'''
!'''Bitch'''
|-
| '''Stage 1: Contractions and Cervical Dilation'''
| 1-4 hours
| 2-6 hours
| 2-6 hours
| 2-12 hours
| 6-12 hours
|-
| '''Stage 2: Foetal Expulsion'''
| 12-30 minutes
| 30-60 minutes
| 30-120 minutes
| 150-180 minutes
| 6 hours (up to 24 hours with large litters)
|-
| '''Stage 3: Placental Expulsion'''
| 1 hour
| 6-12 hours
| 5-8 hours
| 1-4 hours
| Placenta Exits with Foetus
|-
|}
** [[Parturition - Cervical Softening - Anatomy & Physiology|Cervical Softening]]
** [[Parturition - Coordinated Myometrial Contraction - Anatomy & Physiology|Coordinated Myometrial Contraction]]
** Voluntary contraction of abdominal muscles
* In most species, expulsion of foetal membranes quickly follows expulsion of the foetus.
* Expulsion of the foetus requires that the chorionic villi become dislodged from the crypts of the maternal side of the [[Female_Reproductive_Tract_-Placenta_-_Anatomy_%26_Physiology|placenta]].
** Brought about by powerful vasoconstriction of arteries in the villi.
*** Vasoconstriction reduces pressure and allows villi to be released from crypts.
'''Normal Parturition'''
{| style="width:75%; height:200px" border="1"
!'''Species'''
!'''Mare'''
!'''Cow'''
!'''Ewe'''
!'''Sow'''
!'''Bitch'''
|-
| '''Stage 1: Contractions and Cervical Dilation'''
| 1-4 hours
| 2-6 hours
| 2-6 hours
| 2-12 hours
| 6-12 hours
|-
| '''Stage 2: Foetal Expulsion'''
| 12-30 minutes
| 30-60 minutes
| 30-120 minutes
| 150-180 minutes
| 6 hours (up to 24 hours with large litters)
|-
| '''Stage 3: Placental Expulsion'''
| 1 hour
| 6-12 hours
| 5-8 hours
| 1-4 hours
| Placenta Exits with Foetus
|-
|}