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Rat Reproduction - Anatomy & Physiology (view source)
Revision as of 13:54, 5 July 2012
, 13:54, 5 July 2012no edit summary
==Male ==
===Penis ===
= Male =
== Penis ==
* Penis is easily extruded from the prepuce.
* Penis is easily extruded from the prepuce.
* Os penis lies within the tissue of the penis.
* Os penis lies within the tissue of the penis.
== Testes ==
=== Testes ===
* Two testes in an external scrotum.
* Two testes in an external scrotum.
* Head and tail of the epididymis are the sites of extremely large fat pads.
* Head and tail of the epididymis are the sites of extremely large fat pads.
== Accessory Sex Glands ==
=== Accessory Sex Glands ===
Rats have highly developed accessory sex glands. These produce a gelatinous copulatory plug, which is visible in the vagina post-mating and is thought to prevent semen leaking out.
Rats have highly developed accessory sex glands. These produce a gelatinous copulatory plug, which is visible in the vagina post-mating and is thought to prevent semen leaking out.
== Puberty and Sexual Maturity ==
==== Seminal Vesicles ====
* Lie dorsolateral to the urinary bladder in contact with the rectum dorsally.
* Large and lobated, opening into the lower end of the ductus deferens.
* Each is enclosed in a capsule together with the coagulating gland.
==== Prostate Gland ====
* Bilateral and has three lobes: the dorsal, lateral and ventral.
* Dorsal is known as the '''Coagulating Gland'''.
* Lies close to the seminal vesicle.
==== Ampullary Glands ====
* The glands of the ductus deferens.
* Lie near the bladder.
==== Bulbourethral Glands ====
* Found near the urethra as it exits the pelvis.
==== Preputial Glands ====
* Lie in the subcutaneous fat near the penis and open into the prepuce.
* Sebacious glands that secrete a [[Attractivity Behaviour - Anatomy & Physiology#Pheromones|pheromone]] used for scent marking.
* Regress with age and fill with stagnant [[Skin_- Anatomy & Physiology#Glands|sebum]].
=== Puberty and Sexual Maturity ===
* Sexually mature at 6-8 weeks
* Sexually mature at 6-8 weeks
== Mammary Gland ==
=== Mammary Gland ===
* Teats are absent.
* Teats are absent.
== Female ==
= Female =
=== Reproductive tract ===
== Reproductive tract ==
==== Ovary ====
* Right ovary is located at the level of L4-5 just caudal to the right kidney.
* Right [[Ovary - Anatomy & Physiology|ovary]] is located at the level of L4-5 just caudal to the right [[Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidney]].
* Left ovary is located at the level of L5-6 caudal to the left kidney.
* Left [[Ovary - Anatomy & Physiology|ovary]] is located at the level of L5-6 caudal to the left [[Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidney]].
** Nearer the midline than the right ovary.
** Nearer the midline than the right [[Ovary - Anatomy & Physiology|ovary]].
* Both ovaries are embedded in fat.
* Both [[Ovary - Anatomy & Physiology|ovaries]] are embedded in fat.
* Oviduct is convoluted and winds around the ovary in 10-12 loops.
==== Oviduct ====
* [[Oviduct - Anatomy & Physiology|Oviduct]] is convoluted and winds around the [[Ovary - Anatomy & Physiology|ovary]] in 10-12 loops.
==== Uterus ====
* [[Uterus - Anatomy & Physiology#Anatomical_Types_of_Uteri|Duplex Uterus]]
** Two [[Cervix - Anatomy & Physiology|cervices]]
** Uterine horns remain separate until uniting in a single [[Vagina and Vestibule - Anatomy & Physiology|vagina]].
==== Vagina ====
* Vaginal opening lies caudal to clitoral glands and is closed by a membrane until puberty.
* Vaginal opening lies caudal to clitoral glands and is closed by a membrane until puberty.
** '''Clitoral (Preputial) Glands''': Lie in subcutaneous fat near the clitoris and open into a preputial fold.
** '''Clitoral (Preputial) Glands''': Lie in subcutaneous fat near the clitoris and open into a preputial fold.
*** Sebacious glands that secrete a pheramone used for scent marking.
*** Sebacious glands that secrete a [[Attractivity Behaviour - Anatomy & Physiology#Pheromones|pheromone]] used for scent marking.
==== Attachments and Blood Supply ====
* Anastamoses between the ovarian and uterine artery occur in the uterine mesentery.
* Anastamoses between the ovarian and uterine artery occur in the uterine mesentery.
* Mesovarium and mesometrium contain large volumes of fat, which surround the kidneys, abdominal wall and intestinal loops.
* Mesovarium and mesometrium contain large volumes of fat, which surround the [[Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidneys]], abdominal wall and [[Alimentary_- Anatomy & Physiology|intestinal loops]].
== Oestrous Cyclicity ==
===Oestrous Cyclicity ===
* Non-seasonal polyoestrus
* Non-seasonal polyoestrus
* LH surge (responsible for ovulation) is strongly linked to circadian rhythm and usually occurs in the late afternoon.
* LH surge (responsible for [[Ovulation - Anatomy & Physiology|ovulation]]) is strongly linked to circadian rhythm and usually occurs in the late afternoon.
* [[Female_Reproductive_Tract_-Oestrous_Cycle_-_Anatomy_%26_Physiology|Oestrus cycle]] 4-5 days.
* [[Oestrous Cycle - Anatomy & Physiology|Oestrus cycle]] 4-5 days.
* Duration of oestrus is ~14 hours.
* Duration of oestrus is ~14 hours.
== Copulation ==
=== Gestation and Offspring ===
==== Gestation ====
* Gestation length is 20-22 days.
* [[Placenta - Anatomy & Physiology|Placenta]] is haemochorial.
== Gestation and Offspring ==
==== Litter ====
* Litter size 6-16
* Litter size 6-16
* Altricial young
* Altricial young
* Care not to stress mother or she may cannibalise the young.
* Care not to stress mother or she may cannibalise the young.
=== Mammary Gland and Lactation ===
* The rat has 6 pairs of mammary glands.
* 6 pairs of mammary glands.
* Thoracic and inguinal glands act as two discrete complexes, separated by a space just behind the ribs.
* Thoracic and inguinal glands act as two discrete complexes, separated by a space just behind the ribs.
** During lactation, the thoracic glands expand rostrally as far as the parotid and mandibular glands.
** During lactation, the thoracic glands expand rostrally as far as the [[Salivary_Glands_-_Anatomy_&_Physiology#Major_Salivary_Glands|parotid and mandibular glands]].
*** Cranially and medially over the upper forelimb and along the lateral thoracic wall.
*** Cranially and medially over the upper forelimb and along the lateral thoracic wall.
** Inguinal gland covers the lateral abdominal wall back to the stifle and anal region.
** Inguinal gland covers the lateral abdominal wall back to the stifle and anal region.
* At the base of each teat the transition zone between hairless and hair has large sebacious glands.
* At the base of each teat the transition zone between hairless and hair has large sebacious glands.
==== Cervical gland ====
* Rudimentary
==== Thoracic gland ====
* Diffuse.
* Contains 3 nipples
* Surrounds the base of the forelimb.
==== Abdominal gland ====
* Only marginally developed.
==== Inguinal gland ====
* Surrounds the base of the hindlimb.
* Contains 3 nipples.
[[Category:Small Mammal Reproduction]][[Category:Bullet Points]]