All rights reserved. Attention, men: In the last second your bodies each produced at least 1, sperm cells. Now researchers have unlocked just how this seminal feat is possible. For the past 40 years scientists have thought stem cells in the testicles—also called germline stem cells—become sperm only through a simple, two-step process. Not so. Germline stem cells, it seems, can become sperm in several different ways, according to new experiments with mice. Explore an interactive of the human body.
How a Man Produces 1, Sperm a Second
Sperm is the male reproductive cell. In the types of sexual reproduction known as anisogamy and its subtype oogamy , there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon , whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote.
Sperm production is hormonally driven. Brain hormones govern sperm production and are precisely controlled. The hypothalamus secretes gonadotropin-releasing hormone GnRH , which acts on the anterior pituitary gland, stimulating it to release follicle stimulating hormone FSH and leutinizing hormone LH. FSH and LH are released into the bloodstream and act only on the testes to encourage spermatogenesis within seminiferous tubules action of FSH and testosterone production by neighboring Leydig cells action of LH between the seminiferous tubules Figure 1.
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. The mitotic division of these produces two types of cells. Type A cells replenish the stem cells, and type B cells differentiate into spermatocytes.