Female Reproductive SystemOvaries-The ovaries are considered the primary reproductive organs in the female. They are primary because they produce the female ovum and the female sex hormones (estrogen and progestin). Cattle, Doe, Ewes are monotonous, normally giving birth to one young each gestation period. Therefore, one ovum is produced each estous cycle. Swine are polytocus, producing 10 to 25 ova each estrus cycle and giving birth to several young each gestation period. The ovary of the cow is described as almond-shaped, but the shape is altered by growing follicles or copora lutea. The size will change do to active ovaries are larger than inactive ovaries. One ovary is frequently larger than the other in a given cow. The ovaries of the ewe and doe are almond-shaped and less than half the size of those of a cow. The ovaries in the sow are slightly larger than those found in the ewe and appears as a "cluster of grapes".
Oviducts -The oviducts are a pair of convoluted tubes extending from near the ovaries to and becoming continuous with the tips of the uterine horns. Their functions include of ova and spermatozoa, which must be conveyed in opposite directions. In addition they are the site of fertilization and the early cell divisions of the embryo. Histologically, they contain three distinct cell layers. The outer layer, basically connective tissue, is the tunica serosa. The middle layer, composed of both circular and longitudinal smooth muscle fibers, is the tunica muscularies. The innermost layer, Which contains both ciliated and secretory epithelial cells, is the tunica mucosa. The same basic histological arrangement is found in the remainder of the female duct system with some differences in the inner two layers, which will be noted which be noted when we discuss specific organs. Uterus- The uterus extends from the uterotubal junctions to the cervix. For the cow, sow the overall length may range from 35 to 60 cm. For the sow, doe, ewe, and cow the uterine horns account for 80 to 90% of the total length, but in the mare the uterine account for about 50% of the total length. The uteri of the ewe and doe are less than half the size of the other mentioned species.The major function of the uterus is to retain and nourish the embryo, or fetus. Before the embryo becomes atatched to the uterus, the nourishment comes from yolk within the embtyo or from uterine milk which is secreted by glands in the mucosal layer of the uterus. After attachment to the uterus, nutrients and waste products are conveyed between materal and embryonic, or fetal, blood by way of the placenta. Cervix- While technically a part of the uterus, the cervix will be discussed as a distinct organ. It is thick-walled and inelastic, the anterior end being continuous with the body of the uterus while the posterior end protrudes into the vagina. For most farm species the length will range from 5 to 10 cm with an outside diameter of 2 to 5 cm. It contains a canal which is the opening into the uterus. The primary function of the cervix is to prevent microbial contamination of the uterus; however, it also may serve as a sperm reservoir after mating. Semen is deposited into the cervix during natural mating in sows. Vagina-The vagina is tubular in shape, thin-walled and quite elastic. It is from 25 to 30 cm in length in the cows, and 10 to 15 cm in length in the sow, doe, and ewe. In the cow, doe, and ewe, semen is deposited into the anterior end of the vagina, near the opening to the cervix, during natural mating.The vagina is the female organ of copulation. Vulva- The vulva, or external genitalia, consist of the vestibule with related parts and the labia. The vestibule is that portion of the female duct system that is common to both the reproductive and urinary systems. It is from 10 to 12 cm in length in cow. The vestibule joins the vagina at the external urethral orifice. A hymen at that point is less prominent in the cow. A sub urethral diverticulum is located just posterior to the external urethral orifice. Poultry "Female" Reproduction System
Overy- containing immature and mature follicles.
The mature follicles consist of the egg "yolk" and the unfertilized
ovum.
• Infundibulum- yolk with attached ovum is snatched up by the infundibulum. It is at this point in the reproductive tract that the ovum is fertilized if the hen has been mated with a cockerel. Spermatozoa from the cockerel are stored in "sperm nests" located within the infundibulum and are capable of fertilizing ova for up to 30 days after mating. •Magnum- while traveling through this part of the oviduct, the albumin or egg white is formed. •Isthmus- the tough outer membrane located just beneath the egg shell is formed in this part of the oviduct. •Uterus- also referred to as the "shell gland", this is where the egg shell is formed. Most of the transit time from ovulation until the egg is laid is spent in the uterus. •Vagina- the egg travels through the vagina into the cloaca, from which it is "laid." •Cloaca- this is the common external opening from which the contents of the urinary tract (urates), the intestinal tract (feces) and the reproductive tract (eggs) exit the hen. |
Male ReproductiveSystem
Testicles- Production
of the spermatozoa that will become the sperm cells Production of testosterone,
the ‘male’ hormone. The testicle is the entire organ, consisting of the testis
(plural: testes), the scrotum (outer covering of skin), and beginning of the
epididymis
Epididymis- After leaving the testes through ducts in the seminiferous tubules, sperm enter the epididymis. The epididymis is a tubular structure located on one side of the testes. It is packed with a milky nutritive substance as well as spermatozoa from the testes. Spermatozoa mature in the epididymis Vas Deferens- From the epididymis, spermatozoa enter the vas deferens. This carries the spermatozoa into the body cavity towards the urethra. It is surrounded by muscles that contract during ejaculation. Urethra- The urethra extends to the tip of the penis, where it exits the body. Urethra surrounded by smooth muscle – crucial for ejaculation. Penis- Penis is composed of sponge-like blood tissue. Under sexual stimulation, this tissue fills with blood, enlarging it and enabling it to be inserted into a female’s vagina. Poultry "Male" Reproductive SystemMale birds have two functional bean-shaped testes located within the body, just above the kidneys. This is in contrast to many female birds in which the right ovary regresses, leaving just one functional left ovary. The testes grow in size as the bird reaches sexual maturity. In seasonal breeders, the testes enlarge during the breeding season and often change color - from yellow to white in most birds. Immature or inactive testes are yellow in color due to the acumulation of lipids. During the onset of breeding, the testes change to a white color due to the increase in the size of the siminiferus tubules. The testes are covered by a very thin tunic. The bulk of the testis is composed of numerous convoluted seminiferous tubules. Sperm cells are formed in the tubules. Sperm formation occurs more rapidly in birds as compared to mammals. The testes also produce the male hormone testosterone. This hormone is very important in stimulating growth of the male reproductive tract, the development of secondary sexual characteristics such as courtship behavior and aggression and, in chickens, the combs and wattles. Once the sperm leave the testes, they travel through a small tube, known as the epididymis. The avian epdidymis is very small in the bird and is not divided into three parts, the head, the body and the tail as in mammals. Sperm then enter the ductus deferens a long narrow tube that travels next to the ureter and enters the cloaca. The ductus is densely packed with sperm during the breeding season. It takes from one to four days for the sperm to travel from the testes to the end of the ductus. Sperm undergo maturation in the male reproductive tract. In psittacines (parrots), the main storage place for the sperm is the ductus deferens. In passerines (finches, canaries, etc.) sperm is stored in the "seminal glomus", a convoluted structure at the end of the ductus. The right and left seminal glomis form a projection in the cloaca known as a cloaca promatory which can be used to sex passerines. The spermatazoon is composed of an acrosome, a head and a tail. The acrosome contains an enzyme which enables the sperm to penetrate the egg. Psittacines do not have a phallus. They mate by joining their cloacas, with the male ejaculating sperm into the female's cloaca. Some species of birds - such as ostriches, ducks, geese, swans, chickens and turkeys do have a phallus - but it is different from the mammalian phallus. Castration of male birds has been considered by some as a way of curbing aggressive behavior. The surgery is more complex than in mammals, since the avian testes are located within the body - unlike mammalian testes which are located outside the body. Two incisions are necessary to remove the avian testes - one on the right and one on the left.
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