Male Reproductive System

A man’s sex drive is mainly in his head. Two areas of the brain, the cerebral cortex and limbic system, are vital to a man’s sex drive and performance. The cerebral cortex is the gray matter that makes up the outer layer of the brain. It’s the part of your brain that’s responsible for higher functions, such as sensation, movement, and thinking. This includes thinking about sex. When you become aroused, signals that originate in the cerebral cortex speed up your heart rate and blood flow to your genitals. They also signal the process that creates an erection.

 Testosterone is the hormone most closely associated with male sex drive. Produced mainly in the testicles, testosterone has a crucial role in a number of body functions, including:

·         development of male sex organs

·         growth of body hair

·         bone mass and muscle development

·         deepening of the voice in puberty

·         sperm production

·         production of red blood cells

Testosterone levels tend to be higher in the morning and lower at night. In a man’s lifetime, his testosterone levels are at their highest in his late teens, after which they slowly begin to decline. This affects the resolution phase, taking longer before you can be ready for orgasm.  It is not usually that noticeable until after the age of 40.  

Inside Body:

Scrotum or scrotal sac- the small sac, containing the testicles, that hangs between a man’s legs.

Testicles- the sensitive egg-shaped sperm-production organs that hang in the scrotal sac.  They are the size and shape of a large nut, approximately 1 ½ inches long; contain a long tube approximately one one/thousandth of an inch in diameter and  about one thousand feet long; and are able to produce 500 million sperm every day.  Usually the left testicle hangs lower than the right. 

Sperm or spermatozoa- the male seed, manufactured in the testicles, fertilizes the female egg.  This seed contains the genetic information that ultimately determines a baby’s sex.  In sexual intercourse it is ejected through the penis into the female’s vagina.  The cells measure about one six-hundredth of an inch from head to tail. 

Epididymis- the little channel in the scrotal sac where sperm manufactured in the testicles undergo a maturing process. 

Spermatic duct (vas deferens) - the duct from the epididymis that carried the sperm into the ampulla chamber.  In a vasectomy for sterilization of the husband, a one inch section of vas deferens is removed.

Ampulla chamber- the storage chamber for sperm that have left the epididymis and traveled through the spermatic duct. 

Seminal vesicle- the organ producing the seminal fluid that carries the sperm to the prostate gland.

Ejaculatory duct- the organ that expels the sperm and seminal fluid through the penis into the female.

Prostate gland- an important gland, shaped like a large walnut, which contracts and aids in the ejaculation.  It produces additional seminal fluid and contains the nerves that control the erection of the penis. 

 

Cowper’s gland - the first gland to function when a man is sexually aroused.  It sends a few drops of slippery fluid into the urethra, thus preparing it for the safe passage of sperm by neutralizing the acids of the urine that would otherwise kill the sperm. 

Urethra- the tube that carries urine from the bladder through the penis for elimination.  It also carried the sperm and semen from the prostate through the penis.

Outside Body:

Penis - the male sex organ through which both the urine and the sperm are released.   It can be distended with blood under mental or physical stimulus so that it becomes stiff or erect.  The penis is made up of three columns of spongy, erectile tissue, the middle one containing the urethra.  The length of the non-stimulated penis varies greatly, but the length of the erect penis is almost always six to seven inches.  The crown or rim of the glans becomes harder than the tip during erection, helping to arouse excitement in the female during friction.  Circumcision also enables this rim to stand out more from the adjacent tissue of the penis. 

Glans penis- the head of the penis; the very sensitive part of the organ that under friction stimulates ejaculation of the sperm and seminal fluid.

Foreskin- the loose skin that covers the glans penis for protection.  A substance called smegma often gathers under the foreskin producing an offensive odor.  For this reason the penis should be washed daily.  This is removed in those who have been circumcised.

Areas of sexual sensitivity- the male genital organs- comprising of the penis, the scrotal sac, and the area around them- that are exceptionally sensitive to touch.  When caressed affectionately by the wife, they produce a pleasurable sexual excitement that prepares the husband for intercourse, usually in a very few minutes.

Nocturnal emission (wet dream) - a natural occurrence that can be an unsettling experience for a boy who is unprepared for it.  If he awakens to find his pajamas wet and sticky or hardened to a starchy consistency, he may be needlessly alarmed.  What has happened is that pressure has built up because of the increasing rate at which sperm are manufactured.  The seminal vesicles and the prostate gland are filled to capacity with fluid, so that the entire reproductive system is waiting for an explosion.  This is regulated by his hormones.  Sometimes under these condition a dream during the night will cause the penis to fill with blood, thus producing an erection. Cowper’s gland puts forth its neutralizing drops of fluid into the urethra, and then the ejaculatory muscles, or ducts, and the sperm and seminal fluids are merged and spurt forth through the urethra and the penis.  Throughout a boy’s teen years there will be many such nocturnal explosions.  The constant production of sperm and seminal fluid is one of the factors that causes the man to be the usual initiator for sex. 

Ejaculation- the sexual climax when the fluid is forced from the storeroom through small tubes that meet in the ejaculatory duct just before entering the base of the penis.  The muscular contractions that take place at the base of the penis force the seminal fluid past the prostate gland, where it picks up more secretions, then through the urethral canal and out the urethra to aid in the work of impregnating the female.  This fluid can be projected forcefully for a distance of twelve to twenty-four inches.  It is generally agreed that the half teaspoonful of semen ejaculated during a normal sexual contact after a two or three day abstinence will contain about 250 to 500 million sperm cells.  The semen is primarily protein, similar to egg white, and is not dirty or unsanitary, though it has a distinctive odor. 

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