What activity during oocyte activation prevents penetration by additional sperm?
The first sperm to penetrate the oocyte triggers a sequence of changes that block entry by other sperm, or polyspermia. Polyspermy is prevented by depolarization of the egg membrane by opening of sodium channels and by the cortical reaction triggered by the release of calcium ion from smooth ER within the oocyte. The calcium ion stimulates the vesicles to undergo exocytosis. Their contents cause the zona pellucida to harden, creating a barrier against further sperm penetration.
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The abdominopelvic regions found on the same plane as the ilium are the
A. inguinal. B. iliac. C. hypogastric. D. a and b. E. a, b, and c.
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A. human chorionic gonadotropin B. testosterone C. luteinizing hormone D. follicle-stimulating hormone
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A) blood viscosity B) vessel diameter C) turbulence D) vascular resistance E) kidney disease
________ is the process in which ________ forces water and small solutes, such as salts, through narrow clefts between capillary cells.
A. Osmosis; osmotic pressure B. Active transport; osmotic pressure C. Active transport; hydrostatic pressure D. Osmosis; hydrostatic pressure E. Filtration; hydrostatic pressure