Diphenyltetrazolium bromide, a yellow tetrazole is reduced by metabolically active cells to form insoluble, purple formazan dye crystals detected at 570nm

TLS Online TPP Program

#Id: 7590

#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

TLS Online TPP Program

#Id: 7591

#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

 

TLS Online TPP Program

#Id: 7592

#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

TLS Online TPP Program

#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

TLS Online TPP Program

#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

TLS Online TPP Program

#Id: 7595

#Unit 5. Developmental Biology

Chemotactic compounds hormone Progesterone,  made by the cumulus cells, might trigger the release of Protein kinase A from the sperm cell membrane, & allowing it to activate the sperm-specific cation CatSper channels would facilitate the transfer of calcium ions into the sperm, where they would cause exocytosis of the acrosome