Exam 1 - mammals Flashcards
Chemotaxis
Cell movement in response to chemical signal
Thermotaxis
Cell movement in response to temperature changes
Rheotaxis
Cell movement in response to a current
Oviduct
Fallopian tube
Ampulla
Segment of mammalian oviduct near the ovary, where fertilization takes place
Cumulus Layer
A cluster of cells that surround the oocyte
Cumulus-Oocyte Complex
A single oocyte surrounded by the cumulus cells within an extracellular matrix
Zona Pellucida
Glycoprotein extracellular matrix around the mammalian egg (vitelline envelope for mammals)
Polyspermy
- Slow block that releases Juno
- Slow block that disables Z2
Contact and Recognition
May be chemotaxis. Progesterone
Thermotaxis after capacitation
Capacitation
A set of physiological changes by which mammalian sperm become capable of fertilizing an egg
- ability to perform acrosome reaction
- ability to bind to eg
Acrosome reaction
Happens before sperm reach the cell and after capacitation. If a sperm has not gone through capacitation, they will bind to ZP3 and then begin acrosome reaction before binding to ZP2
“humanized” mouse embryos & Zona proteins
Mouse cells with human ZP2 in the zona pellucida could bind sperm
ICSI
A procedure that involves injecting a single sperm directly into an egg in vitro.
Zona reaction
After sperm fertilizes an egg, the cortical granules release enzymes that digest the proteins ZP2 and ZP3, preventing them from binding to sperm
Calcium Waves
Zinc Spark
When sperm bind to the egg, a rush of zinc is released into the zona pellucida. May:
- inhibit enzymes that digest zona pellucida
-Alter sperm movement
-Act as a chemoreppelent to counteract progesterone
- Disrupt Juno-Izumo interaction
Mammalian cleavage
Rotational Holoblastic Cleavage
- Slow
-Asynchronous
-Compact at 8 cell
Compaction
Cells in the 8 cell embryo change their adhesive properties and become tightly attached to each other
Ovastacin
A protease released by the cortical granules after fertilization to digest ZP2
Juno
Protein found on the mammalian oocyte that binds to Izumo, a protein on sperm
