Male Reproductive System PDF Download

Human’s reproductive system is located in pelvic cavity which is formed by pelvis bones. The pelvis (plural: pelves) is a set of bones(2 in number). Many people think of the pelvis as the hip bone, because it is at the hip. The pelvis is at the lower end of the spine. In vertebrates, the legs are attached at the pelvis.

The function of the pelvis is to protect the organs used for digesting and for reproduction (making babies). It is also important for bearing some load.

The pelvis is symmetrical. It is made of the following bones:

1. The hip bone made of:

•  The top part is the ilium
•  The middle part (the upper part of the loops) is called pubis
• The lower part (the lower part of the loops) is called ischium

2. The sacrum
3. The coccyx 

The male reproductive system includes the following structures:

1.     Penis
2.     Scrotum
3.     Testes (testicles)
4.     Vas deferens
5.     Seminal vesicles
6.     Prostate gland
7.     Urethra

Penis

The penis is the male sex organ, reaching its full size during puberty. In addition to its sexual function, the penis acts as a conduit for urine to leave the body.

The penis is made of several parts:

Glans (head) of the penis -

It is the sensitive bulbous* structure at the distal* end of the human penis. In uncircumcised men, the glans is covered with pink, moist tissue called mucosa. Covering the glans is the foreskin (prepuce). In circumcised men, the foreskin is surgically removed and the mucosa on the glans transforms into dry skin.

Bulbous – fat/round

Distal- situated away from the centre of the body or from the point of attachment.

Corpus cavernosum -

Two columns of tissue running along the sides of the penis. Blood fills this tissue to cause an erection.

Corpus spongiosum -

 A column of sponge-like tissue running along the front of the penis and ending at the glans penis; it fills with blood during an erection, keeping the urethra -- which runs through it -- open. The urethra runs through the corpus* spongiosum, conducting urine out of the body.

(Corpus - the main body or mass of a structure)

An erection results from changes in blood flow in the penis. When a man becomes sexually aroused, nerves cause penis blood vessels to expand. More blood flows in and less flows out of the penis, hardening the tissue in the corpus cavernosum.

 Scrotum –

The scrotum is a pouch-like structure that hangs behind the penis. It holds and protects the testicles. One testis is typically lower than the other, which functions to avoid compression in the event of impact. The scrotum acts as a climate control system, allowing the testicles to be slightly away from the rest of the body and keeping them slightly cooler than normal body temperature for optimal sperm development. The muscles in the scrotum, called the cremasteric muscles, move the testicles slightly within the scrotum depending on the surrounding temperature.

Testes (testicles)-

The testes (or testicles) are two olive-sized oval bodies, one on the right side and one on the left side. The testes have two main functions:

·         to produce sperm (the male reproductive cell), and

·         to produce testosterone (the male sex hormone).

The epididymides and the vasa deferentia are attached to the testicles and are important in transporting sperm cells after they develop in the testes.

The term testicles includes the testes as well as the surrounding structures, such as the vas deferens and the epididymis. These two names, testes and testicles, are often used interchangeably even though their definitions are slightly different.

Epididymis-

 The epididymis is a long, coiled tube that rests on the backside of each testicle. It transports and stores sperm cells that are produced in the testes. It also is the job of the epididymis to bring the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens.

 Vas deferens-

 The vas deferens is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra, the tube that carries urine or sperm to outside of the body, in preparation for ejaculation.

Seminal vesicles-

The seminal vesicles are sac-like pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles produce a sugar-rich fluid (fructose) that provides nutrients for the sperm and lubricates the urethra. This fluid mixes with other fluids to create the semen. The fluid of the seminal vesicles makes up most of the volume of a man's ejaculatory fluid, or ejaculate.

Prostate –

 The prostate is a walnut-sized gland located between the bladder and the penis. The prostate is just in front of the rectum. The urethra runs through the center of the prostate, from the bladder to the penis, letting urine flow out of the body.

The prostate secretes fluid that nourishes and protects sperm. During ejaculation, the prostate squeezes this fluid into the urethra, and it’s expelled with sperm as semen.

Bulbourethral glands -

Also called Cowper's glands(2 in number), these are pea-sized structures located on the sides of the urethra just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.

 Ejaculatory ducts-

These are formed by the fusion of the vas deferens and the seminal vesicles (see below). The ejaculatory ducts empty into the urethra.

Urethra- 

The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of ejaculating semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.

How Does the Male Reproductive System Function?

The entire male reproductive system is dependent on hormones, which are chemicals that regulate the activity of many different types of cells or organs. The primary hormones involved in the male reproductive system are follicle-stimulating hormone, luteinizing hormone, and testosterone.

Follicle-stimulating hormone is necessary for sperm production (spermatogenesis), and luteinizing hormone stimulates the production of testosterone, which is also needed to make sperm. Testosterone is responsible for the development of male characteristics, including muscle mass and strength, fat distribution, bone mass, facial hair growth, voice change, and sex drive.

Terms Related to Penis–

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Genetial(s) – Male’s Reproductive organs.

Dick / Penis / Cock - External Sexual Organ.

Boner - spontaneous erections that occur during sleep or while waking up at morning.

Morning Wood – Non Sexual Erection during and immediately following sleep.

Circumcision - Male circumcision is the removal of the foreskin from the human penis.In the most common procedure, the foreskin is opened, adhesions are removed, and the foreskin is separated from the glans.

An intromittent organ is a general term for an external organ of a male organism that is specialized to deliver sperm during copulation. When animal/human sexual behaviour is reproductively motivated, it is often termed mating or copulation

Pubic hair - Pubic hair is body hair found in the genital area of adolescent and adult humans, located on and around the sex organs, the crotch, and sometimes at the top of the inside of the thighs, in the pubic region around the pubis bone.

Puberty / sexual development - Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction.

To read more about Testicles, Scortum, Epididymis and Urethera please download PDF file.

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