Changes

= Introduction =

= Introduction =

The vagina constitutes the part of the female reproductive tract between the [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] and the vulva.  With the vestibule and vulva, it is the copulatory organ and the birth canal.  The '''hymen''' is the poorly developed, vestigial, mucosal folds at the junction of the vagina and vestibule.

The vagina constitutes the part of the female reproductive tract between the [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology|cervix]] and the vulva.  With the vestibule and vulva, it is the copulatory organ and the birth canal.  The '''hymen''' is the poorly developed, vestigial, mucosal folds at the junction of the vagina and vestibule.

= Anatomical Boundaries =

= Anatomical Boundaries =

== Vagina ==

== Vagina ==

* Extends from the external ostium of the [[Female_Reproductive_Tract_-The_Uterus_-_Anatomy_%26_Physiology|uterus]] to the entrance of the [[Urethra_-_Anatomy_%26_Physiology|urethra]].

* Extends from the external ostium of the [[Female_Reproductive_Tract_-The_Uterus_- Anatomy & Physiology|uterus]] to the entrance of the [[Urethra_- Anatomy & Physiology|urethra]].

* Long and thin walled.

* Long and thin walled.

* Located in the median position within the pelvic cavity.

* Located in the median position within the pelvic cavity.

* Located between the [[Rectum_-_Anatomy_%26_Physiology|rectum]] dorsally and [[Urinary_Bladder_-_Anatomy_%26_Physiology|bladder]] ventrally.

* Located between the [[Rectum_- Anatomy & Physiology|rectum]] dorsally and [[Urinary_Bladder_- Anatomy & Physiology|bladder]] ventrally.

* Mostly retroperitoneal, but the cranial parts are covered by [[Peritoneal_Cavity_-_Anatomy_%26_Physiology|peritoneum]].

* Mostly retroperitoneal, but the cranial parts are covered by [[Peritoneal_Cavity_- Anatomy & Physiology|peritoneum]].

=== Vaginal Fornix ===

=== Vaginal Fornix ===

* Protruding [[Female_Reproductive_Tract_-The_Cervix_-_Anatomy_%26_Physiology|cervix]] restricts the lumen of the cranial vagina to a ring-like space known as the fornix.

* Protruding [[Female_Reproductive_Tract_-The_Cervix_- Anatomy & Physiology|cervix]] restricts the lumen of the cranial vagina to a ring-like space known as the fornix.

* This is a cranioventral recess in the mare and bitch.

* This is a cranioventral recess in the mare and bitch.

* The recess is caudoventral in the cow and ewe.

* The recess is caudoventral in the cow and ewe.

* Lies mostly behind the ischial arch, sloping ventrally to its opening at the vulva.

* Lies mostly behind the ischial arch, sloping ventrally to its opening at the vulva.

* The wall contains vestibular glands.   

* The wall contains vestibular glands.   

** Secretions from these glands keeps the mucosa of the vestibule moist and facilitates [[Reproductive_Behaviour_-_Copulatory_Behaviour_-_Anatomy_%26_Physiology|coitus]] and [[Reproductive_System_-_Anatomy_%26_Physiology#Parturition|parturition]].

** Secretions from these glands keeps the mucosa of the vestibule moist and facilitates [[Reproductive_Behaviour_-_Copulatory_Behaviour_- Anatomy & Physiology|coitus]] and [[Reproductive_System_- Anatomy & Physiology#Parturition|parturition]].

** At [[Reproductive_Behaviour_-_Oestrus_Behaviour_-_Anatomy_%26_Physiology|oestrus]], the odour of these secretions sexually stimulates the male.

** At [[Reproductive_Behaviour_-_Oestrus_Behaviour_- Anatomy & Physiology|oestrus]], the odour of these secretions sexually stimulates the male.

=== Vestibular Bulbs ===

=== Vestibular Bulbs ===

* Present in the mare and bitch

* Present in the mare and bitch

* Dark patches on the vestibular walls mark the position of vestibular bulbs.

* Dark patches on the vestibular walls mark the position of vestibular bulbs.

* Vestibular bulbs are a concentration of veins forming erectile tissue, this is the female homologue of the bulb of the [[Male_Reproductive_Tract_-The_External_Genetalia_-_Anatomy_%26_Physiology|penis]].

* Vestibular bulbs are a concentration of veins forming erectile tissue, this is the female homologue of the bulb of the [[Male_Reproductive_Tract_-The_External_Genetalia_- Anatomy & Physiology|penis]].

* During the dog's [[Reproductive_Behaviour_-_Copulatory_Behaviour_Dog_-_Anatomy_%26_Physiology|'tie']], the bulbs are erect and press against the [[Male_Reproductive_Tract_-The_External_Genetalia_-_Anatomy_%26_Physiology|penis]], caudal to the enlarged bulb of the glans.

* During the dog's [[Reproductive_Behaviour_-_Copulatory_Behaviour_Dog_- Anatomy & Physiology|'tie']], the bulbs are erect and press against the [[Male_Reproductive_Tract_-The_External_Genetalia_- Anatomy & Physiology|penis]], caudal to the enlarged bulb of the glans.

== Vulva ==

== Vulva ==

=== Clitoris ===

=== Clitoris ===

* Partial homologue of the [[Male_Reproductive_Tract_-The_External_Genetalia_-_Anatomy_%26_Physiology|penis]].

* Partial homologue of the [[Male_Reproductive_Tract_-The_External_Genetalia_- Anatomy & Physiology|penis]].

* Located within the ventral commissure of the vulva.

* Located within the ventral commissure of the vulva.

* Can be divided into two parts:

* Can be divided into two parts:

* Found radiographically in some bitches.

* Found radiographically in some bitches.

* Homologue of the [[Male_Reproductive_Tract_-The_External_Genetalia_-_Anatomy_%26_Physiology#Glans_Penis_morphology|os penis]]

* Homologue of the [[Male_Reproductive_Tract_-The_External_Genetalia_- Anatomy & Physiology#Glans_Penis_morphology|os penis]]

= Histology =

= Histology =

* The wall consists of:

* The wall consists of:

** Mucosal layer lined by stratified squamous epithelium

** Mucosal layer lined by stratified squamous epithelium

** Layer of [[Muscles_-_Anatomy_%26_Physiology#Smooth_Muscle|smooth muscle]]

** Layer of [[Muscles_- Anatomy & Physiology#Smooth_Muscle|smooth muscle]]

*** Inner circular and outer longitudinal layers

*** Inner circular and outer longitudinal layers

** Outer layer of adventitia

** Outer layer of adventitia

** Not lined by Mesothelium

** Not lined by Mesothelium

*** Merges with the adventitial layers of the [[Urinary_Bladder_-_Anatomy_%26_Physiology|bladder]] anteriorly and [[Rectum_-_Anatomy_%26_Physiology|rectum]] posteriorly.

*** Merges with the adventitial layers of the [[Urinary_Bladder_- Anatomy & Physiology|bladder]] anteriorly and [[Rectum_- Anatomy & Physiology|rectum]] posteriorly.

* This combination of elastic fibres and [[Muscles_-_Anatomy_%26_Physiology#Smooth_Muscle|muscular]] layers allows the massive distension that occurs during [[Reproductive_System_-_Anatomy_%26_Physiology#Parturition|parturition]].

* This combination of elastic fibres and [[Muscles_- Anatomy & Physiology#Smooth_Muscle|muscular]] layers allows the massive distension that occurs during [[Reproductive_System_- Anatomy & Physiology#Parturition|parturition]].

* After [[Reproductive_Behaviour_-_Copulatory_Behaviour_-_Anatomy_%26_Physiology|coitus]], contraction of the smooth muscle layer ensures that the pool of semen remains within the cervical region.

* After [[Reproductive_Behaviour_-_Copulatory_Behaviour_- Anatomy & Physiology|coitus]], contraction of the smooth muscle layer ensures that the pool of semen remains within the cervical region.

* When relaxed, the vaginal wall collapses to obliterate the lumen and the vaginal epithelium is thrown into folds.

* When relaxed, the vaginal wall collapses to obliterate the lumen and the vaginal epithelium is thrown into folds.

* The dense lamina propria contains:

* The dense lamina propria contains: