Search results
Results from the WOW.Com Content Network
Levels of estrogen that are too high can be detrimental to spermatogenesis due to suppression of gonadotropin secretion and by extension intratesticular testosterone production. [35] The connection between spermatogenesis and prolactin levels appears to be moderate, with optimal prolactin levels reflecting efficient sperm production. [28] [36]
Sperm quantity and quality are the main parameters in semen quality, which is a measure of the ability of semen to accomplish fertilization. Thus, in humans, it is a measure of fertility in a man . The genetic quality of sperm, as well as its volume and motility, all typically decrease with age . [ 17 ]
The sperm and the ovum are known as the gametes (each containing half the genetic information of the parent, created through meiosis). [citation needed] The sperm (being one of approximately 250 million sperm in a typical ejaculation) travels through the vagina and cervix into the uterus or fallopian tubes. Only 1 in 14 million of the ...
Sperm Spermiogenesis is the final stage of spermatogenesis , during which the spermatids develop into mature spermatozoa . At the beginning of the stage, the spermatid is a more or less circular cell containing a nucleus , Golgi apparatus , centriole and mitochondria ; by the end of the process, it has radically transformed into an elongated ...
A 1992 World Health Organization report described normal human semen as having a volume of 2 mL or greater, pH of 7.2 to 8.0, sperm concentration of 20×10 6 spermatozoa/mL or more, sperm count of 40×10 6 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid ...
The immature spermatozoa or sperm are then sent to the epididymis, where they gain a tail, enabling motility. Each of the original diploid germ cells or primary spermatocytes forms four functional gametes, each forever young. [clarification needed] The production and survival of sperms require a temperature below the normal core body ...
Spermatogonia going through mitosis to form primary spermatocytes in Grasshopper testes. Spermatocytogenesis. At puberty, spermatogonia located along the walls of the seminiferous tubules within the testis will be initiated and start to divide mitotically, forming two types of A cells that contain an oval shaped nucleus with a nucleolus attached to the nuclear envelope; one is dark (Ad) and ...
In hermaphroditic fish, some are male and female at the same time while in other fish they are serially hermaphroditic; starting as one sex and changing to the other. In at least one hermaphroditic species, self-fertilization occurs when the eggs and sperm are released together. Internal self-fertilization may occur in some other species. [44]