spermatozoa

Examples of spermatozoa in the following topics:

• Semen

  • Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa.
  • In humans, seminal fluid contains several components besides spermatozoa, including enzymes (proteolytic and others) and fructose.
  • These elements promote the survival of spermatozoa and provide a medium for motility.
  • The seminal plasma provides a nutritive and protective medium for the spermatozoa during their journey through the female reproductive tract.
  • According to the World Health Organization, normal human semen has a volume of 2 ml or greater, pH of 7.2 to 8.0, sperm concentration of 20×106 spermatozoa/ml or more, sperm count of 40×106 spermatozoa per ejaculate or more, and motility of 50% or more within 60 minutes of ejaculation.

• Spermatogenesis

  • These develop into mature spermatozoa, also known as sperm cells.
  • Thus, the primary spermatocyte gives rise to two cells, the secondary spermatocytes, which in turn produce four spermatozoa.
  • Spermatozoa are the mature male gametes in many sexually reproducing organisms.
  • While in the epididymis, the spermatozoa gain motility and become capable of fertilization.
  • The resulting spermatozoa are now mature but lack motility, rendering them sterile.

• Accessory Sex Glands

  • About 50 - 70% of seminal fluid in humans originates from the seminal vesicles, but is not expelled in the first ejaculate fractions which are dominated by spermatozoa and zinc-rich prostatic fluid.
  • The high fructose concentrations provide nutrient energy for the spermatozoa when stored in semen in the laboratory.
  • The prostate secretes a slightly acidic fluid, milky or white in appearance, that usually constitutes 20–30% of the volume of the semen along with spermatozoa and seminal vesicle fluid.
  • The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa.
  • This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizes traces of acidic urine in the urethra, and helps flush out any residual urine or foreign matter.

• Sperm

  • The uniflagellated sperm cells (with one flagellum) of animals are referred to as spermatozoa.

• Hormonal Regulation of the Male Reproductive System

  • Its presence in males is necessary for the maturation of spermatozoa.
  • Increasing the levels of FSH increases the production of spermatozoa by preventing the apoptosis of type A spermatogonia.

• Physiological Processes in Sponges

  • Sponges may also become sequentially hermaphroditic, producing oocytes first and spermatozoa later.
  • Oocytes arise by the differentiation of amoebocytes and are retained within the spongocoel, whereas spermatozoa result from the differentiation of choanocytes and are ejected via the osculum.
  • Ejection of spermatozoa may be a timed and coordinated event, as seen in certain species.
  • Spermatozoa carried along by water currents can fertilize the oocytes borne in the mesohyl of other sponges.

• Scrotum

  • It has been suggested that if testes were situated within the abdominal cavity, they would be subjected to the regular changes in abdominal pressure that are exerted by the abdominal muscles, resulting in the more rapid emptying of the testes and epididymis of sperm before the spermatozoa were matured sufficiently for fertilization.

• Female Duct System

  • This fluid contains nutrients for spermatozoa, oocytes, and zygotes.

• Overview of the Male and Female Reproductive Systems

  • The primary direct function of the male reproductive system is to provide the male gamete or spermatozoa for fertilization of the ovum.
  • The final category, used for copulation and deposition of the spermatozoa (sperm) within the female, includes the penis, urethra, vas deferens, and Cowper's gland.

• Testes Ducts

  • Seminiferous tubules, located in the testes, are where meiosis occurs and the gametes (spermatozoa) are created.