The testicles, known medically as testes (singular testis), are the male generative glands in animals. Male mammals have two testicles, contained within an extension of the abdomen called the scrotum.
Between the seminiferous tubules are special cells called interstitial cells (Leydig cells) where testosterone and other androgens are formed.
Like the ovaries (to which they are homologous), testicles are components of both the reproductive system (being gonads) and the endocrine system (being endocrine glands). The respective functions of the testicles are:
- producing sperm (spermatozoa)
- producing male sex hormones, of which testosterone is the best known
Both functions of the testicle, sperm-forming and endocrine, are under control of gonadotropic hormones produced by the anterior pituitary:
- luteinizing hormone (LH)
- follicle-stimulating hormone (FSH)
Under a tough fibrous shell, the tunica albuginea, the testis contains very fine co...