Difference between revisions of "Rat Reproduction - Anatomy & Physiology"
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m (Text replace - "[[Reproductive_Behaviour_-_Attractivity_Behaviour_- Anatomy & Physiology" to "[[Attractivity Behaviour - Anatomy & Physiology") |
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==== Ovary ==== | ==== 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]]. | + | * Right [[Ovary - Anatomy & Physiology|ovary]] is located at the level of L4-5 just caudal to the right [[Macroscopic 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]]. | + | * Left [[Ovary - Anatomy & Physiology|ovary]] is located at the level of L5-6 caudal to the left [[Macroscopic Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidney]]. |
** Nearer the midline than the right [[Ovary - Anatomy & Physiology|ovary]]. | ** Nearer the midline than the right [[Ovary - Anatomy & Physiology|ovary]]. | ||
* Both [[Ovary - Anatomy & Physiology|ovaries]] are embedded in fat. | * Both [[Ovary - Anatomy & Physiology|ovaries]] are embedded in fat. | ||
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* 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 [[Renal Anatomy - Anatomy & Physiology#Common Anatomy|kidneys]], abdominal wall and [[Alimentary_- Anatomy & Physiology|intestinal loops]]. | + | * Mesovarium and mesometrium contain large volumes of fat, which surround the [[Macroscopic 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 [[ | + | * LH surge (responsible for [[The_Ovary_-_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. | * [[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 ==== | ==== Gestation ==== | ||
− | * Gestation length is 20-22 days. | + | * [[Reproductive System - Anatomy & Physiology#Gestation|Gestation]] length is 20-22 days. |
− | * [[ | + | * [[Gestation_-Placenta_- Anatomy & Physiology|Placenta]] is haemochorial. |
==== Litter ==== | ==== Litter ==== | ||
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− | [[Category:Small Mammal Reproduction | + | [[Category:Small Mammal Reproduction]] |
Revision as of 15:27, 1 December 2010
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
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.