fertility
How long is sperm viable in reptiles?
4 to 5 years
What happens to sperm during fertilization in the oviduct?
change in movement patterns from straight(ish) line to hyperactive movement
What is the acrosome reaction?
The steps for proper fusion between the spermatozoal membrane and the outer acrosomal membrane
What happens in fertilization after complete penetration of the spermatozoon?
It reaches the perivitelline space where it settles into a bed of microvilli. It requires fusion of the equatorial segment and the oocyte plasma membrane (when the second polar body comes out of the egg), and fusion proteins complete the fertilization process
What is polyspermy?
Fertilization by multiple spermatozoa
How long is sperm viable in bats?
4 to 5 months
How does spermatazoa bind to the Zona Pellucida?
What must occur for the sperm to bind properly?
Zona Pellucida binding proteins on sperm
capacitation
What happens during vesiculation?
acrosomal contents are dispersed and the sperm nucleus is left with the inner acrosomal membrane surrounding, separates normal from a damaged acrosome
When does the cortical reaction occur?
During the first and second meiotic divisions?
How can polyspermy occur?
When the cortical reaction alters the zona pellucida to reduce binding capabilities, after entry, the sperm becomes a male pronucleus
What is it called when you get multiple sires in the same litter?
superfecundation
What is the makeup of the Zona Pellucida?
3 glycoproteins, binding sites
What does the acrosomal enzyme release allow during the acrosome reaction?
spermatozoon to digest its way through the zona pellucida, which is driven by acrosin, which hydrolyzes zona proteins and enhances the sperm's ability to bind to the zona
What does the cortical reaction utilize?
small dense granules: cortical granules
How does sperm become the male pronucleus?
Must decondense by removing the disulfide cross-linking via glutathione
What is the fertile period of a human?
5-6 days
What are the three glycoproteins in the Zona pellucida and their functions?
Zona proteins 1 and 2 are structural
Zona protein 3 is more like a receptor, sperm binding needs 10,000 to 50,000
What does a damaged acrosome (head defect) cause?
osmotic pressure, sudden cooling or heating, changes in pH, premature loss in acrosomal contents, rapid vesiculation
What does exocytosis to release contents initiate?
Zona Block
What is syngamy?
the fusion of male and female pronucleus to form large diploid nucleus
What are the 8 major steps for fertilization?
hyperactive motility, binding to zona pellucida, acrosomal reaction, penetration of zona pellucida, sperm oocyte membrane fusion, sperm engulfed, decondensation of sperm nucleus, formation of male pronucleus
What are the binding sites present on the Zona Pellucida
Primary zona binding region for adherence of spermatozoa and holding it in position (key)
Secondary binding site for the acrosome reaction promoting ligand, helps initiate the acrosomal reaction (gas pedal)
What are the functions of the acrosome reaction?
enables spermatozoa to penetrate the zona pellucida at specific locations
exposes the equatorial segment so it can fuse with the plasma membrane of the oocyte
cortical reaction, which prevents penetration by other spermatozoa, exocytosis to release contents, initiating the zona block
What begins after syngamy?
embryogenesis