Difference between revisions of "Rat Reproduction - Anatomy & Physiology"

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

Revision as of 13:52, 22 July 2008

BACK TO REPRODUCTIVE SYSTEM
BACK TO SMALL DOMESTIC MAMMALS


Male

Penis

  • Os penis lies within the tissue of the penis.


Testes

  • Two testes in an external scrotum.
  • Testes descend between day 30-40.
  • Open inguinal canals throughout life.
    • Allows the testes to shrink and return to the abdomen during the non-breeding season.
  • Head and tail of the epididymis are the sites of extremely large fat pads.

Puberty and Sexual Maturity

  • Sexually mature at 6-8 weeks


Mammary Gland

  • Teats are absent.

Female

Reproductive tract


Oestrous Cyclicity

  • Non-seasonal polyoestrus
  • Oestrus cycle 4-5 days.
  • Duration of oestrus is ~14 hours.


Copulation

  • Evidence that mating has occured is the 'copulatory plug'
    • Forms in the vagina.


Gestation and Offspring

  • Gestation length is 20-22 days.
  • Litter size 6-16
  • Altricial young
    • Eyes open at 12-14 days.
  • Earliest weaning age 21 days.
  • Care not to stress mother or she may cannibalise the young.


Mammary Gland

  • 5 pairs of teats.
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