Where is sperm deposited during mating

Artificial insemination also is performed if sperm penetration of the cervical mucus is a deterrent to fertility or if mating is impractical. With livestock, semen is either collected using an artificial vagina or obtained by electrical stimulation of the reproductive tract. The male is allowed to mount and attempt to mate a restrained teaser animal while the penis is manually diverted into the artificial vagina.

Rams, boars, and stallions can be trained to mount a dummy. Electroejaculation involves placement of a bipolar electrode over the accessory glands by way of the rectum; this method is an alternative to the artificial vagina if the male is unable or unwilling to mount. Professional AI services generally collect semen from bulls twice a week.

Fertility of an ejaculate is ultimately judged by inseminating females and determining rates of pregnancy or nonreturn to estrus. Until actual breeding data can be compiled, a predicted judgement of fertility is based on a laboratory examination of semen samples.

Criteria used to judge a semen sample include cellular concentration, proportion of live to dead cells, morphology, and motility. The fertilizing capacity of human ejaculates have been enhanced using laboratory techniques Figure One quality bovine ejaculate can yield enough motile cells to impregnate several hundred females. Diluents have been developed that not only extend the semen sample, but protect it during freeze-thaw Table Methods of cryopreservation of sperm cells have best been worked out for cattle.

Breed organizations of certain species eg. Insemination units are aliquoted into polyvinyl chloride straws or glass ampules, sealed, and frozen. A second series of microscopic evaluations of an ejaculate are usually performed after thawing. An inseminating catheter loaded with semen is manipulated through the cervix per rectum in the cow Figure - semen can be deposited at midcervix or into the uterine body just beyond the anterior end of the cervix a small amount can be discharged into the cervical canal while withdrawing the insemination rod.

Ewes can be inseminated with the use of a vaginal speculum, however, passage of an inseminating rod through the cervix is difficult; injection of semen into the uterus with the aid of a laparoscope is gaining in popularity. A spiral-tipped inseminating tube designed after the corkscrew-like boar penis can be introduced directly into the cervix of the pig without cervical stabilization.

In species such as dogs, semen is probably deposited largely into the vagina, but also forced into the uterus. Despite these differences in deposition site and significant differences in the number of sperm ejacuated, there is remarkably little variation among species in the total number of sperm that reach the oviducts.

Typicially, a few hundred to a few thousand sperm reach the oviducts following a single mating, which usually represents far less than one percent of the sperm in the ejaculate. The vagina represents a hostile environment for sperm, and their continued survival depends on getting into more hospitable regions of the female tract.

In their journey from vagina to oviduct, sperm must overcome a series of barriers, each of which eliminates a substantial proportion of the original population of sperm:. The cervix connects the vagina to the uterus. The cervical canal follows an irregular, tortuous route, and the epithelium contains many deep crypts.

The cervical epithelium is richly endowed with mucus-secreting cells, and, as a consequence, the lumen is filled with mucus. Interestingly, the consistency and viscosity of cervical mucus is under endocrine control. When estrogen levels are high and progesterone levels low, as occurs prior to ovulation, cervical mucus becomes watery and its mucin strands assume a parallel orientation.

This state apparently greatly facilitates passage of sperm through the cervical canal. Conversely, when progesterone concentrations are high, as in the luteal phase of the cycle, cervical mucus becomes exceptionally viscous and disorganized, which largely precludes entry of sperm into the uterus. The uterus does not present an active barrier, but sperm must somehow be transported directionally along its length.

Studies in several species have shown that sperm are able to get from the distal uterus to the oviducts in times as short as a few minutes, which is much too fast to be explained by sperm motility.

Moreover, dead sperm and inanimate sperm-sized particles are rather efficiently transported upward through the uterine lumen. The conclusion from these types of studies is that sperm transport in the uterus is largely a result of uterine contractions, and that sperm motility plays a minor if any role in the process.

In most, but not all species, the uterus is also a site hostile to sperm. In many animals, sperm within the uterus are rapidly phagocytosed.

In other cases, sperm can remain viable in the uterus for several days, but their fertility rapidly declines. The vagina meets the outside at the vulva, which also includes the labia, clitoris, and urethra.

The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the Fallopian tubes. At certain intervals, approximately every 28 days, the ovaries release an ovum that passes through the Fallopian tube into the uterus. If the ova is fertilized by sperm, it attaches to the endometrium and the fetus develops. In months when fertilization does not occur, the lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through a process known as menstruation.

Privacy Policy. Skip to main content. The Reproductive System. Search for:. Overview of the Reproductive System. Overview of the Male and Female Reproductive Systems The human reproductive system functions to produce human offspring, with the male providing sperm and the female providing the ovum. Learning Objectives Summarize the reproductive systems of men and women. Key Takeaways Key Points The male reproductive system consists of external organs. The testes in the scrotum produce the male gamete, sperm, which is ejaculated in seminal fluid by the penis.

The female reproductive system primarily consists of internal organs. The female gamete, ovum, is produced in the ovaries and is released monthly to travel to the uterus via the Fallopian tubes.