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Sperm motility. Sperm motility describes the ability of sperm to move properly through the female reproductive tract (internal fertilization) or through water (external fertilization) to reach the egg. Sperm motility can also be thought of as the quality, which is a factor in successful conception; sperm that do not "swim" properly will not ...
Method. The Ericsson method is based on the belief that X-sperm swim slower than Y-sperm. Sperm are placed atop a "column" of increasingly thicker layers of albumin, and allowed to swim down into the solution. After a certain time period has elapsed, the sperm can be separated into the faster and slower swimmers.
Sperm activation has been shown to be caused by calcium ionophores in vitro, progesterone [2] released by nearby cumulus cells and binding to ZP3 of the zona pellucida. The initial change is called "hyperactivation", which causes a change in spermatozoa motility. They swim faster and their tail movements become more forceful and erratic.
They swim faster and their tail movements become more forceful and erratic. A recent discovery links hyperactivation to a sudden influx of calcium ion into the tails. The whip-like tail (flagellum) of the sperm is studded with ion channels formed by proteins called CatSper. These channels are selective, allowing only calcium ions to pass.
The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. [ 5 ] Females and young males live together in groups, while mature males (bulls) live solitary lives outside of the mating season. The females cooperate to protect and nurse their young.
The decline in the numbers of sperm that swim to the oviduct is one of two ways that prevents polyspermy in humans. The other mechanism is the blocking of sperm in the fertilized egg. [7] According to Developmental Biology Interactive, if an egg becomes fertilized by multiple sperm, the embryo will then gain various paternal centrioles.
The sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions. However, most fish do not possess seminiferous tubules. Instead, the sperm are produced in spherical structures called sperm ampullae. These are seasonal structures, releasing their contents during ...
Capacitation is the penultimate [1] step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. [2] This step is a biochemical event; the sperm move normally and look mature prior to capacitation. In vivo, capacitation occurs after ejaculation, when the spermatozoa leave the vagina and enter ...