Human Reproductive System

The two labia minora meet at the clitoris, a small, sensitive protrusion in females that is comparable to the penis in males. The clitoris is covered by a fold of skin, called the prepuce, which is similar to the foreskin at the end of the penis. Like the penis, the clitoris is very sensitive to stimulation and can become erect.

Spermatogenesis is the process by which male primary germ cells undergo division, and produce a number of cells termed spermatogonia, from which the primary spermatocytes are derived. Each primary spermatocyte divides into two secondary spermatocytes, and each secondary spermatocyte into two spermatids or young spermatozoa.

A thick white opaque fluid that is secreted by seminal vesicals, glands that open into the urethra is called semen.. The function of semen is to protect the sperm cells in the vagina, provide energy for weakened sperm cells, and help contract the uterine muscle to move the sperm cells into the uterus faster.

A small walnut-shaped wrinkled bag of skin holds the testicles and is called the scrotum. Muscle fibers in the scrotum contract to help hold the sperm producing testicles closer to the body when warmth is needed and relax to allow the testicles to move farther away when it is too warm.

Vasectomy is a surgical sterilization procedure performed on males, involving the cutting or sealing of the vas deferens to prevent sperm from mixing with semen during ejaculation. It is a permanent birth control method for men. Tubal ligation is the equivalent female sterilization procedure, performed on the fallopian tubes.

Conversion of spermatid into spermatozoa is called spermiogenesis. 

Semen consists of sperms and secretion from seminal vesicles, prostate and cowper's glands.

The primary spermatocycte formed during spermatogenesis is diploid (2n).

In humans, spermatocytes are nourished by sertoli cells.

The release of sperms from the seminiferous tubule is called spermiation.

One primary spermatocyte can produce 4 sperms.Therefore, 10 primary spermatocytes can produce 40 sperms.

Acrosome of sperm secretes  sperm lysins like hyaluronidase.

It is determined at the time when the embryo starts to develop.

 Vitelline duct also called umbilical duct appears in human embryo at the end of fourth week and it connects the yolk sac of embryo to the mid-gut.

Trestolone is an anabolic steroid that has been shown to significantly reduce sperm count.