Simple Pharmanotes: Male reproductive system

Introduction:

Reproduction is the ability of individual to produce a new individual, and is considered as one of vital sign of living organisms,
Human life starts when a male gamete called “Sperm” fuses with female gamete called “Ovum” to form a single cell called “Zygote”.
Male and female reproductive organs are called “Gonads” they are responsible for production of sex hormones and gametes.

It is a muscular sac covered with highly pigmented skin, present behind penis, held hanging between the legs.
Scrotum is divided into two compartments by scrotal septum, one houses each testes.
The scrotum is supplied with two muscles,

These muscles relax and contract as per body's temperature to keep the temperature of testes 2 to 4 degrees lesser than body temp.

These are male gonads.
They produce male gamete “Sperm” and androgen “Testosterone.”
They are “Two” in number, oval in shape and are housed in the each compartment of scrotal sac.
Length is 4-5 cm.
They are covered with two layers of connective tissues,

Tunica albuginea also distributes parts of ovaries in 300 to 400 compartments called “Lobules” by forming curtain-like structures called “Septa”.
Each lobules contain “Seminiferous tubules” the site where sperm production takes place.
The process of sperm production is called “Spermatogenesis.”
Spermatogenesis starts from the basement membrane of seminiferous tubules resulting in maturation of Germ cells to sperms.
In between the developing Germ cells there are some elongated cells called “Sertoli cells” they form a protective”Blood-testis barrier” and also control sperm production by forming a hormone called “Inhibin' '.
The formed sperms are then stored in a structure adjoining testes called “Epididymis”, which acts as “Storage and maturation site of sperms”
During ejaculation the sperms are transferred from epididymis to vas deferens (ductus deferens).
Surrounding the seminiferous tubules there are scattered “Leydigs Cells” that secrete male sex hormone “Testosterone”.

There are two vasa deferentia.
Also called “ductus deferens”
They are thick muscular tubes arising from epidermis and go through the “Inguinal canal” into the pelvic cavity.
They can be accessed in scrotum as they form a part of “Spermatic cord”, they can be cut to prevent the transfer of sperms into the semen.
The surgical removal of small parts of vas deferens is called as “Vasectomy” and is a “Permanent Sterilization method” for males.
Vas deferens ends behind the prostate gland by forming a flask like structure called ampoula which forms “ejaculatory duct” along with seminal vesicle.

These are slender glandular structures present on either side of the prostate gland.
The seminal vesicle along with the ampulla of vas deferens forms a structure called “ejaculatory duct” where sperms coming from vas deferens mixes with secretion of seminal vesicle.
Seminal vesicle’s secretion forms 60% of the bulk of Semen (A thick milky white liquid ejaculated by male during sexual intercourse).
Secretion of seminal vesicles is rich in fructose which is utilized by sperms as energy source for travel in the female reproductive system.

Neutralizing acidity of urethra to protect sperms.
Coagulating and decoagulating the semen in female reproductive system (This provides time to the sperms to utilize fructose in semen for further movement)

Also called “Cowper’s Glands”.
They are situated at the base of the penis and joined to the urethra.
They secrete a thick salty secretion that neutralizes the acidic environment of urethra present in penis called “Penile Urethra” and in female vagina.
The secretions are secreted just before the ejaculation and also called pre-ejaculate, it doesn't contain sperm but may carry sperms present in urethra.

The penis is the male organ of copulation (sexual intercourse).
It is flaccid for non-sexual actions, such as urination, and turgid and rod-like with sexual arousal.
When erect, the stiffness of the organ allows it to penetrate into the vagina and deposit semen into the female reproductive tract.
Penis consists of a body, glans penis and root.
The body of the penis is made up of three cylindrical masses of erectile tissue.
The two lateral masses are called the corpora cavernosa.
The smaller middle part which contains the urethra is called corpus spongiosum.
The lower end of the corpus spongiosum is slightly enlarged called the glans penis.
The glans penis is covered with the folded skin called the prepuce (foreskin).
An erection and the enlargement of penis are maintained by parasympathetic division of the spinal cord.