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Sperm cells cannot divide and have a limited lifespan, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell with 46 paired chromosomes.
A single Sertoli cell extends from the basement membrane to the lumen of the seminiferous tubule, although the cytoplasmic processes are difficult to distinguish at the light microscopic level. Sertoli cells serve a number of functions during spermatogenesis, they support the developing gametes in the following ways:
Because its main function is to nourish developing sperm cells through the stages of spermatogenesis, the Sertoli cell has also been called the "mother" or "nurse" cell. [10] Sertoli cells also act as phagocytes, consuming the residual cytoplasm during spermatogenesis. Translocation of cells from the basal lamina to the lumen of the ...
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 ...
The sperm cell of Homo sapiens is the small reproductive cell produced by males, and can only survive in warm environments; upon leaving the body, it starts to degrade, thereby decreasing the total sperm quality. Sperm cells normally come in two types, "female" and "male", named for the resulting sex of the fertilized zygote each produces after ...
Spermatogenesis as the cells progress from spermatogium, to primary spermatocytes, to secondary spermatocytes, to spermatids and to sperm. Spermatocytes are a type of male gametocyte in animals. They derive from immature germ cells called spermatogonia. They are found in the testis, in a structure known as the seminiferous tubules. [1]
The produced sperm are stored in the epididymides until ejaculation through the vasa deferentia. The sperm cells are motile and they swim using tail-like flagella to propel themselves towards the ovum. The sperm follows temperature gradients (thermotaxis) [7] and chemical gradients to locate the ovum.
Sperm motility is dependent on several metabolic pathways and regulatory mechanisms. The axonemal bend movement is based on the active sliding of axonemal doublet microtubules by the molecular motor dynein, which is divided into an outer and an inner arm. Outer and inner arm plays different roles in the production and regulation of flagellar motility: the outer arm increase the bea