The Reproductive System A Practical Guide Unlike other animals, humans can CHOOSE when they want to reproduce.

Male Reproductive System Seminal vesicle-semen Ductus deferens-sperm duct Prostate-semen Urethra-urine Penis Epididymis-sperm maturation Testis-sperm formation Scrotum-cools testis

Scrotum Sac of loose skin, fascia & smooth muscle divided into two pouches by a septum *Temperature regulation of testes *Sperm survival requires 2-3 degrees lower temperature than core body temperature Muscle in scrotum Elevates testes on exposure to cold & during arousal Warmth reverses the process

Testosterone is responsible for many of the "male" characteristics. Testes - make sperm via meiosis. The testes are also responsible for producing testosterone, the male hormone. Testosterone is responsible for many of the "male" characteristics. Septum Lobule Seminiferous tubule Capsule

Spermatogenesis *Spermatogenesis is the production of sperm by meiosis. *Occurs in the seminiferous tubules in the testes.

(1) Spermatogonia are the Germ-Line cells. They are diploid (2n) (1) Spermatogonia are the Germ-Line cells. They are diploid (2n). They undergo mitosis to reproduce themselves. (2) One of these spermatogonia undergoes meiosis, and it is called a primary spermatocyte. It is diploid (2n). (3) The primary spermatocyte undergoes MEIOSIS I to produce two secondary spermatocytes. These are now haploid (n) but still contain two chromatids per chromosome (4) Each of these secondary spermatocytes undergoes MEIOSIS II to each produce two spermatids. Spermatids are haploid (n) and each contain 1 chromosome that was previously a chromatid. The result is 4 total spermatids. (5) Spermatids mature into the sperm we know, and these sperm cells are called spermatozoa. They are then ready to leave the body and fertilize an egg!

Rete testes – carries sperm from seminiferous tubules to efferent ducts; sperm become concentrated and excess fluid reabsorbed; if this doesn’t occur, sperm may not concentrate and male may not be fertile Epididymus - collects mature sperm which is eventually propelled through the vas deferens Vas (ductus) deferens -sperm travel through this tube, joins with urethra   Bulbourethral glands – produce lubricating fluid to cleanse urethra prior to ejaculation Seminal vesicle – comprises most of sperm; contains fructose, sugary fluid that supplies energy for sperm to move

Anatomy of the sperm cell Acrosome – the cap on top of the sperm cell that contains enzymes that help penetrate the egg membrane during fertilization

Vasectomy - the tube is cut to prevent sperm leaving (and fertilizing an egg) This procedure can be done right in the doctor's office

New Reversible Vasectomy in Clinical Trials See http://www.wired.com/magazine/2011/04/ff_vasectomy/ for full story and VIDEO! "Das gathered a fold of skin, made a puncture, and reached into the scrotum with a fine pair of forceps. He extracted a white tube: the vas deferens, which sperm travel through from the testes to the penis. In a normal vasectomy, Das would have severed the vas, cauterized and tied up the ends, and tucked it all back inside. But rather than snipping, Das took another syringe, delicately slid the needle lengthwise into the vas, and slowly depressed the plunger, injecting a clear, viscous liquid. He then repeated the steps on the other side of the scrotum." The procedure is RISUG (for reversible inhibition of sperm under guidance) The substance that Das injected was a nontoxic polymer that forms a coating on the inside of the vas. As sperm flow past, they are chemically incapacitated, rendering them unable to fertilize an egg.

Circumcision Boys are born with a hood of skin, called the foreskin, covering the head (also called the glans) of the penis. In circumcision, the foreskin is surgically removed, exposing the end of the penis.

See also: Kidshealth Male Reproductive WORD BANK Vas deferens Bladder Vas deferens Scrotum Urethra Seminal Vesicle Prostate Urethra Prostate Epididymus Epididymus Bladder Teste Scrotum Teste Seminal Vesicle See also: Kidshealth Male Reproductive

Male Reproductive Health Recommended after age 50 - prostate exam Doctors use the digital rectal exam (DRE) as a relatively simple test to check the prostate