Ejaculation is the discharge of semen from the male reproductive tract as a result of an orgasm. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception.

​Puberty is the process in which a human child’s body matures into an adult capable of sexual reproduction. It is initiated by hormonal signals from the brain to the ovaries in females and testes in males, also known as the gonads. In response to these signals, the gonads produce the hormones required for the physiological transformation of the human body, including changes to the sex organs and the stimulation of sexual desire in people (i.e., the libido).

​Vasectomy is a surgical procedure for male contraception. It is intended to be a permanent form of contraception and, along with condoms, is one of the only methods of birth control available for men.

​Mitochondria are known as the powerhouses of the cell as they are responsible for cell respiration (the process which produces energy). Their most prominent function is to generate adenosine triphosphate (ATP), the energy currency of cells.

​Adenosine triphosphate (ATP) is the primary energy storage molecule used to activate the reactions needed for growth and reproduction by all living organisms. It is an organic compound consisting of an adenosine molecule bonded to three phosphate groups, and it is present in all living tissue.

Testosterone is the primary sex hormone in males and is responsible for the development of male reproductive tissues (e.g., the testes and the prostate), as well as secondary sexual characteristics such as increased muscle mass and the growth of body hair. It is found in men and women, and is integral in regulating health and well-being, including maintaining bone mass.

Seminiferous Tubules are located in the testicles, the two oval-shaped organs on either side of a male’s penis. There are around 800 seminiferous tubules in each testicle, and this is where meiosis and subsequent development of spermatozoa occurs. In a mature adult male, each of these tubules creates thousands of sperm every second.

​The blood–testis barrier is a physical barrier between the blood vessels and the seminiferous tubules of the testes. The term is a bit misleading as it is not a blood-organ barrier, but rather one that is formed by the tight junctions between Sertoli cells of the seminiferous tubules. For this reason, this barrier is also referred to as the “Sertoli cell barrier”. The barrier isolates further developed germ cells from the blood.

Named after Enrico Sertoli, an Italian physiologist, Sertoli cells are a specialized cell type found in the testicles. Specifically, they are located in the seminiferous tubules of the testes and they facilitate the production of new sperm, or, spermatogenesis.