When the stereocilia are pushed toward the kinocilium, the membrane potential is decreased to about –50 mV.

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#Unit 5. Developmental Biology

Hyperactivation mediated by the opening of the sperm specific calcium channels, the CatSper proteins, in the sperm tail.

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#Unit 5. Developmental Biology

Once a sperm has reached the oocyte-cumulus complex, hyperactivation, along with a hyaluronidase enzyme on the outside of the sperm cell membrane, enables the sperm to digest a path through the extracellular matrix of the cumulus cells

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#Unit 5. Developmental Biology

Thermotaxis  The ability to sense temperature difference and preferentially swim from cooler to warmer sites is found only in capacitated sperm

 

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#Unit 5. Developmental Biology

Capacitated mammalian sperm can sense thermal differences as small as 0.014 degrees Celsius over a millimeter and tend to migrate toward the higher temperature

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#Id: 7593

#Unit 5. Developmental Biology

The capacitated sperm are also able to detect and respond to picomolar amounts of the hormone progesterone, which is secreted by the cumulus cells surrounding the egg

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#Id: 7594

#Unit 5. Developmental Biology

Chemotaxis oocyte and its accompanying cumulus cells secrete molecules that attract capacitated sperm toward the egg during the last stages of sperm migration