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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
In this case, however, it seems that sperm selection is more dependent on the ovum. MHC-heterozygous males were found to have significantly more fertilization success than MHC-homozygous males; sperm count, motility, and swimming velocity were not shown to significantly co-vary with similarity or dissimilarity at the MHC.
Hyperactivation is a type of sperm motility.Hyperactivated sperm motility is characterised by a high amplitude, asymmetrical beating pattern of the sperm tail ().This type of motility may aid in sperm penetration of the zona pellucida, which encloses the ovum.
During sperm choice, females are able to discriminate and differentially use the sperm from different males. One instance where this is known to occur is inbreeding; females will preferentially use the sperm from a more distantly related male than a close relative. [52]
Sperm quantity and quality are the main parameters in semen quality, which is a measure of the ability of semen to accomplish fertilization. Thus, in humans, it is a measure of fertility in a man. The genetic quality of sperm, as well as its volume and motility, all typically decrease with age. [17]
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 ...
In both plants and animals, gamete size difference is the fundamental difference between females and males. [2] Anisogamy most likely evolved from isogamy. [3] Since the biological definition of male and female is based on gamete size, the evolution of anisogamy is viewed as the evolutionary origin of male and female sexes.
Motility is the ability of an organism to move independently using metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components.