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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:
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.
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 ...
The "good sperm hypothesis" is very common in polyandrous mating systems. [38] The "good sperm hypothesis" suggests that a male's genetic makeup will determine the level of his competitiveness in sperm competition. [38] When a male has "good sperm" he is able to father more viable offspring than males that do not have the "good sperm" genes. [38]
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
Diagram of human sperm cell. The size of the sperm midpiece is determined in part by the volume of mitochondria in the sperm. [17] Sperm midpiece size is tied to sperm competition in that individuals with a larger midpiece will have more mitochondria, and will thus have more highly motile sperm than those with a lower volume of mitochondria. [17]
Bateman attributed the origin of the unequal investment to the differences in the production of gametes: sperm are cheaper than eggs. A single male can easily fertilize all of a female's eggs; she will not produce more offspring by mating with more than one male. A male is capable of fathering more offspring if he mates with several females.
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 ...