The male reproductive system free essay sample

This paper describes in detail the anatomy and physiology of the human male reproductive system including its organs: testes, scrotum, prostate, spermatic ducts, sex glands, and penis; including the physiology of spermatogenesis, fertilization and the production of hormones by the male reproductive system. Taylor (2013). The Organs of the Male Reproductive System The penis is located above the scrotum and one of its functions is to deliver semen into the female vagina in sexual intercourse which leads to fertilization. The other function of the penis is the excretion of urine through the urethra. The penis is composed of three parts the root, the shaft, and the glans. The root is attached to the wall of the abdomen within the pubic region. The shaft comes immediately after the root of the penis and the glans immediately follows the shaft. The glans, also known as the head of the penis, is covered in loose skin called the foreskin. The opening of the urethra, where urine and semen leave the body, is located at the tip of the glans and is referred to as the external urethral orifice. The penis is mostly cylindrical in shape and is composed of three tubular chambers of spongy-like tissue, this tissue contains thousands of large spaces that are capable of filling with blood with the male is aroused. As blood fills these spaces it stiffens and erects the penis allowing for penetration of the female vagina to occur, thus allowing fertilization to occur. WebMD, LLC. (2013) Testes, or testicles, are located in a pouch-like sac called the scrotum below the penis. Testes are oval in shape and are about the size of a large olive, 1. Inches long and an inch in diameter. Surrounding each testis itself is a white fibrous capsule called the tunica albuginea. The testicles are secured within the scrotum by the spermatic cord that is anchored to the abdomen. They are responsible for producing testosterone and for generating sperm. The production of sperm is accomplished by coiled masses of tubes called seminiferous tubules that are located in lobules within the testes. WebMD (2013). The production of sperm doesn’t occur until a male reaches puberty, typically 13-15 years of age. During puberty a male child starts to produce hormones which affect essentially every aspect of the male physiology. The principle hormone is testosterone which causes, indirectly or directly, growth, muscular build, hair growth in the pubic region and face, as well as hormonal changes in the testes. This hormonal change signals the seminiferous tubules to start producing sperm. Healthline Networks, Inc. (2013). The cells located between the seminiferous tubules in clusters are called interstitial or leydig cells, which are the source of testosterone. This process, the production of sperm, is called spermatogenesis. Spermatogenesis takes place in the testes and epididymis. As mentioned above prior to puberty, there is no spermatogenesis due to the lack of hormonal triggers. At puberty, spermatogenesis begins when luteinizing hormone and follicle stimulating hormone are produced. Luteinizing hormone triggers the production of testosterone by the testes while follicle stimulating hormone triggers the maturation of germ cells. Testosterone stimulates stem cells in the testes known as spermatogonium to undergo the process of developing into spermatocytes. Each diploid spermatocyte goes through the process of meiosis I and splits into two haploid secondary spermatocytes. The secondary spermatocytes go through meiosis II to form four haploid spermatid cells. The spermatid cells then go through a process known as spermiogenesis where they grow a flagellum and develop the structures of the sperm head. After spermiogenesis, the cell is finally a sperm cell, or spermatozoa. The spermatozoa are released into the epididymis where they complete their maturation and become able to move on their own. Saladin, Kenneth S. (2012). Spermatozoa are the male gamete. A single sperm is composed of a head, mid piece and tail or flagellum; all of which only makes up barely . 002 inches in length. The head is composed of a nucleus, acrosome and flagellar basal body. The nucleus is what contains the 23 pairs of chromosomes needed for reproduction. The acrosome is a lysosome in the form of a thin cap covering the posterior upper portion of the nucleus, it also has enzymes that allow it to penetrate a female egg cell or oocyte. The third part of the sperm, the tail, is divided into three parts: midpiece, principal piece and endpiece. This tale allows the sperm to propel it’s self through the female vagina to get to the oocyte. R. Bowen (2000). Sperm makes up the main component of semen. Semen is a fluid that is produced by males that is composed of a number of chemicals suspended in a liquid medium and the aforementioned sperm. A typical ejaculation discharges around two to five ml of semen. Of which thirty percent is prostatic fluid, sixty percent seminal vesicle fluid, and ten percent sperm. This mere ten percent contains, on average, 50 to 120million sperm/ml. The prostatic fluid is composed of a thin, milky white fluid containing calcium, phosphate ions, and citrate. The seminal vesicle fluid is composed of a thicker yellowish fluid containing fructose and other carbohydrates, citrate, prostaglandins and a protein called prosemenogelin. Saladin, Kenneth S. (2012). The semen is ejaculated out of the body by the penis during sexual intercourse. Sperm is produced by the testes but is stored in the epididymis to become fully matured before ejaculation. The epididymis is composed of about two hundred and fifty meters (eight hundred and fifty feet) of long, thin tubules that are tightly coiled into a small mass that wraps around the superior and posterior edge of the testes. Tim Taylor (2013). The scrotum, which houses the testes in a sack like pouch, is composed of skin and muscle and is located inferior to the penis. The smooth muscle located in the scrotum controls the distance between the testes and the body. This is a necessary function of the scrotum to keep the seminiferous tubules at optimal temperature for sperm production. If the testes become too warm to support sperm production the smooth muscle within the scrotum can relax, increasing the distance from the body’s heat and allowing the testes to cool down. Conversely, if the testes become too cold to support sperm production the smooth muscle within the scrotum will contract, decreasing the distance from the body so that the testes will be warmed by the body’s heat. Tim Taylor (2013). Some would say that the scrotum is one of the most fragile structure of the male anatomy, I have been told that it is unbelievably painful when this anatomy is struck with any kind of force. Within the scrotum, as I have mentioned above, a pair of spermatic cords anchors the testes to the abdominal cavity. These spermatic cords include the ductus deferens along with nerves, veins, arteries, and lymphatic vessels that support the function of the testes. These cords pass from abdominal wall through the external inguinal ring into the scrotum. The ductus deferens, also known as the vas deferens, is a muscular tube that carries sperm from the epididymis into the abdominal cavity to the external urethral orifice. The smooth muscles of the walls of the ductus deferens are used to move sperm towards the ejaculatory duct through peristalsis. Tim Taylor (2013). There are three sets of accessory glands in the male reproductive system, of which include: the seminal vesicles, prostate gland, and bulbourethral glands. The seminal vesicles are a pair of glands located behind the bladder, posteriorly. The liquid produced by the seminal vesicles contains proteins and mucus and has an alkaline pH to help sperm survive in the acidic environment of the vagina. The liquid also contains fructose to feed sperm cells so that they survive long enough to fertilize the oocyte. The prostate gland completely surrounds a portion of the urethra, inferior end of the urinary bladder and is about the size of a walnut. The prostate contains smooth muscle tissue that can constrict to prevent the flow of urine or semen. As mentioned above thirty percent of semen is made from secretions from this gland. This fluid is milky white in color and contains enzymes, proteins, and other chemicals to support and protect sperm during ejaculation. The bulbourethral glands, also known as the Cowper’s glands, are a pair of pea-sized exocrine glands located inferior to the prostate and anterior to the anus. It secretes a thin alkaline fluid into the urethra that lubricates the urethra and neutralizes acid from urine remaining in the urethra after urination. These secretions from this gland function to prepare the urethra for the flow of semen prior to ejaculation. One of the functions of the male reproductive system is fertilization. Fertilization is the process by which a sperm combines with an oocyte to produce a fertilized zygote. The sperm released during ejaculation must first swim through the vagina, with the help of its flagellum, the uterus and into the fallopian tubes where they may find an oocyte. After reaching the oocyte, sperm next have to penetrate the outer corona radiata and zona pellucida layers of the oocyte. Sperm contain enzymes in the acrosome region of the head that allow them to penetrate these layers. After penetrating the interior of the oocyte, the nuclei of these haploid cells fuse to form a diploid cell known as a zygote. After the first sperm cell manages to get past these layers the oocyte stops any more sperm cells from getting inside  of it. The zygote cell begins cell division to form an embryo. Saladin, Kenneth S (2012). In conclusion the male reproductive system includes the penis, the scrotum, the testicles, male sex glands, and spermatic ducts. The main functions of the reproductive system are fertilization and the ability to urinate. It also helps to produce hormones that a re useful throughout the body with hair growth and transitioning from a boy to a fully grown mature male. The male reproductive system is far less complicated than the female reproductive system but it is an important part in keeping the human race from perishing.