spermatozoa), from the ancient Greek ?????? (seed) and ??? (alive), is more commonly known as a sperm or sperm cell.
During fertilization, the sperm's mitochondria are destroyed by the egg cell.
The average life span of sperm is between four to six days.
A spermatozoon bearing a Y chromosome will lead to a male (XY) offspring, while a spermatozoon bearing an X chromosome will lead to a female (XX) offspring.
The spermatids then mature into sperm as they lose most of their cytoplasm and develop a flagellated tail.
Once the sperm has bound to ZP3, the fused section of the membranes opens and the nucleus of the sperm is transferred to the egg cytoplasm.
Sperm do not swim randomly; they use various clues and factors to help reach the egg.
Current research at Harvard University has shown that sperm swim from colder to warmer regions (Flam 2006).
Once a sperm is capacitated and reaches the egg, enzymes are released from the acrosome in order to dissolve cell junctions and the zona pellucida coat (Carlson 2003).
Once past this outer layer, a sperm has to surpass the protective glycoprotein coat of the zona pellucida.
The sperm cell contains a minimum amount of cytoplasm.
Together, the sperm cell and ovum form a zygote, or fertilized egg, which can then grow and develop into a new organism.
The midpiece, which is located between the head and tail of the sperm cell, contains centrioles, microtubules, and a mitochondrial spiral.
Spermatids are haploid cells and contain 23 single chromosomes.
Spermatozoa are all derived from germ cells, or the embryonic gonadal cells that produce gametes.
Each of the two secondary spermatocytes divides into two spermatids during the second meiotic division.
The sudden rise in calcium levels in the tail causes increased activity in the flagellum, propelling the sperm more forcefully through the viscous environment of the female uterus.
Once the sperm meets the egg, fertilization can occur.
Sperm cells were first observed by a student of Anton van Leeuwenhoek in 1677.
The Reynolds number associated with spermatozoa is in the order of 1E-2.
Problems with sperm production, motility, or count may lead to infertility.
Essentially, sperm smell their way from the vagina to the to the location of the egg in the distal parts of the female's Fallopian tubes (Flam 2006).
A sperm fertilizes an ovum, which serves as the female haploid gamete.
The largest spermatozoa belongs to the fruit fly.
The sperm begins to swim more rapidly and forcefully.
Sperm production does diminish with age, but never completely ceases.
The process through which a sperm cell breaks through the barriers of the egg is called the acrosomal process.
A third pathology, impairment of sperm transport, may lead to infertility as well.
Some of these spermatogonia continually duplicate themselves through the process of mitosis.
Changes in the egg cell follow and help to prevent polyspermy, or the fertilization of the egg by more than one sperm.
The tail flagellates and propels the human sperm cell at about 1 to 3 mm per minute by rotating like a propeller.
The final maturation process takes place once the sperm cells have moved into the epididymis, where they mature over the 12 days or so.
Non-obstructive azoospermia can be caused by cystic fibrosis, obstruction of various sperm pathways, chemotherapy, and Klinefelter syndrome.
Once a sperm nears an ovum, capacitation and hyperactivity occur.
A recent discovery links hyperactivity to a sudden influx of calcium ions into the tail of the sperm.
The main function of sperm is to fertilize an egg to form a zygote.
Once sperm has entered the female's vagina or cloaca, the sperm begins its task of locating the egg.
A small number indicates viscous forces are dominant and therefore laminar flow is present, meaning sperm cells exhibit smooth and constant fluid motion.
Finally Achilles found his prey; Achilles chased Hector around the wall of Troy three times before Athena, in the form of Hector's favorite and dearest brother, Deiphobus, persuaded Hector to fight face to face.
Other spermatogonia undergo meiosis and eventually develop into sperm.
The entire process, from spermatogonium to mobile and functional sperm, takes approximately 76 days.
Sperm hyperactivity is necessary for breaking through the physical barriers that protect the egg from fertilization.
Once the process of spermatogenesis is complete for one primary spermatocyte, the end result is the creation of four sperm cells.
Unlike many other STDs that can be passed through body fluids, herpes is transmitted by skin-to-skin contact. You can get genital herpes through genital-to-genital or mouth-to-genital contact from an infected person…but it is not passed in semen.