Difference between revisions of "Rat Reproduction - Anatomy & Physiology"
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− | + | ==Male == | |
− | + | ===Penis === | |
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* 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. | ||
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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. | ||
− | == 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. | ||
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− | == 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 == | |
+ | |||
+ | === Reproductive tract === | ||
− | = | + | ==== Ovary ==== |
− | + | * 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 - 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 - Anatomy & Physiology|ovary]]. | ||
+ | * Both [[Ovary - Anatomy & Physiology|ovaries]] are embedded in fat. | ||
− | + | ==== Oviduct ==== | |
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− | * Oviduct is convoluted and winds around the ovary in 10-12 loops. | + | * [[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 ==== | ||
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* 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 | + | *** 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. |
− | * [[ | + | * [[Oestrous Cycle - Anatomy & Physiology|Oestrus cycle]] 4-5 days. |
* Duration of oestrus is ~14 hours. | * Duration of oestrus is ~14 hours. | ||
− | == Gestation and Offspring == | + | === Gestation and Offspring === |
+ | |||
+ | ==== Gestation ==== | ||
+ | |||
+ | * Gestation length is 20-22 days. | ||
+ | * [[Placenta - Anatomy & Physiology|Placenta]] is haemochorial. | ||
+ | |||
+ | ==== Litter ==== | ||
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* 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. | ||
− | == Mammary Gland == | + | === Mammary Gland and Lactation === |
− | * 6 pairs of mammary glands. | + | * 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. | * 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. | ||
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+ | ==== Cervical gland ==== | ||
+ | |||
+ | * Rudimentary | ||
+ | |||
+ | ==== Thoracic gland ==== | ||
+ | |||
+ | * Diffuse. | ||
+ | * Contains 3 nipples | ||
+ | * Surrounds the base of the forelimb. | ||
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+ | ==== Abdominal gland ==== | ||
+ | |||
+ | * Only marginally developed. | ||
+ | |||
+ | ==== Inguinal gland ==== | ||
+ | |||
+ | * Surrounds the base of the hindlimb. | ||
+ | * Contains 3 nipples. | ||
+ | |||
+ | |||
+ | [[Category:Small Mammal Reproduction]][[Category:Bullet Points]] |
Latest revision as of 13:54, 5 July 2012
Male
Penis
- Penis is easily extruded from the prepuce.
- 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.
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.
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 pheromone used for scent marking.
- Regress with age and fill with stagnant sebum.
Puberty and Sexual Maturity
- Sexually mature at 6-8 weeks
Mammary Gland
- Teats are absent.
Female
Reproductive tract
Ovary
- Right ovary is located at the level of L4-5 just caudal to the right kidney.
- Left ovary is located at the level of L5-6 caudal to the left kidney.
- Nearer the midline than the right ovary.
- Both ovaries are embedded in fat.
Oviduct
Uterus
Vagina
- 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.
- Sebacious glands that secrete a pheromone used for scent marking.
- Clitoral (Preputial) Glands: Lie in subcutaneous fat near the clitoris and open into a preputial fold.
Attachments and Blood Supply
- 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.
Oestrous Cyclicity
- Non-seasonal polyoestrus
- LH surge (responsible for ovulation) is strongly linked to circadian rhythm and usually occurs in the late afternoon.
- Oestrus cycle 4-5 days.
- Duration of oestrus is ~14 hours.
Gestation and Offspring
Gestation
- Gestation length is 20-22 days.
- Placenta is haemochorial.
Litter
- 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 and Lactation
- The rat has 6 pairs of mammary glands.
- 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.
- 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.
- During lactation, the thoracic glands expand rostrally as far as the parotid and mandibular 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.