Locate the ovaries, which appear as a mass of follicles just posterior to the kidneys. They are often buried in a mass of fat which should be carefully removed. The adult non-pregnant rat is usually in breeding condition with mature or well developed ova in the ovaries. The oviducts are small highly coiled tubes leading from the ovaries to the uterus. Locate the right and left cornua (horns) of the uterus. The cornua of the uterus unite to form the vagina. Open one cornu of the uterus and examine the interior for embryos which might be present. The vagina leads to the exterior separately from the urethra. The vagina opens to the exterior via the external vaginal orifice which opens just posterior to the urethral opening. The clitoris, which is the female homolog of the male penis, is associated with the urethra and therefore is not connected with the vagina in the rat.
Figure 4: Female urogenital system
Figure 5: A section through a mammalian ovary showing immature and mature (Graafian) follicles.
Examine slide #40 of the ovary. Note the large sac-like follicles in which the ova mature. Some of the follicles may have ova visible within them (Figure 5). When a follicle is ripe and its ovum is mature, it bursts, releasing the ovum which is then picked up by the oviduct. The oviduct is ciliated internally. The cilia beat to create currents to draw the ovum inside and propel it towards the uterus.