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In cartilaginous fish and amphibians, sperm are carried through the archinephric duct, which also partially helps to transport urine from the kidneys. In teleosts , there is a distinct sperm duct, separate from the ureters , and often called the vas deferens, although probably not truly homologous with that in humans. [ 21 ]
A diagram of the mechanism of action of vas-occlusive contraceptive methods. Vas-occlusive contraception is a form of male contraception that blocks sperm transport in the vas deferens, the tubes that carry sperm from the epididymis to the ejaculatory ducts.
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. In mammals, sperm is stored in the epididymis and released through the penis in semen during ejaculation. The word sperm is derived from the Greek word σπέρμα, sperma, meaning "seed".
Pollen tube elongation is an integral stage in the plant life cycle. The pollen tube acts as a conduit to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms.
Vas-occlusive contraception is a form of male contraception that blocks sperm transport in the vas deferens, the tubes that carry sperm from the epididymis to the ejaculatory ducts. Vas-occlusive contraception provides a contraceptive effect through physical blockage of the vas deferens, the duct connecting the epididymis to the urethra.
As they pass by the seminal vesicles, a fluid rich in fructose combines with the sperm. This addition nourishes the sperm in order to keep them active and motile. [ 6 ] Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added. [ 4 ]
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 ...
Sperm entering the caput epididymidis are incomplete—they lack the ability to swim forward (motility) and to fertilize an egg. Epididymal transit takes 2 to 6 days in humans and 10–13 in rodents. [7] During their transit in the epididymis, sperm undergo maturation processes necessary for them to acquire motility and fertility. [8]