Lecture 21: Reproductive Physiology II Flashcards
What is the lifespan of an oocyte? How long can sperm survive in the reproductive tract?
<24 hours. 5 days.
When sperm are ejaculated, the _______ ________ become coated with ________ _________ proteins.
Surface molecules, seminal plasma proteins
What are the five changes that occur within sperm once capacitated (enter the vaginal tract)?
- removal of proteins
- reorganization of plasma membrane
- influx of calcium
- modification of ion channels
- switch to glycolytic metabolism
The first step of fertilization is bypassing the _________ _________. What is the secondary oocyte coated by, that sperm must penetrate?
Corona radiata. Carbs, proteins, hyaluronic acid.
Sperm release ________ from their _____ to break through the corona radiata, and reach the _____ _________.
Hyaluronidase, acrosomes, zona pellucida.
Which glycoproteins make up the human zona pellicuda? Which is the sperm binding protein, and what does it trigger?
ZP1, ZP2, ZP3. ZP3 is sperm binding protein, triggers acrosomal reaction.
The binding of sperm to ZP3 sets of a __________ _____________ _______, leading to an influx of _______.
Signal transduction cascade, calcium
Which enzyme is secreted during the acrosomal reaction?
Acrosin - digests holes in the zona pellicuda.
A variety of _____ and ______ molecules on both the sperm and egg play a role in ______ _______.
Recognition, docking, sperm binding
What are the two blocks to polyspermy (multiple sperm binding)? Describe fast block.
Fast block, slow block. Fast block occurs immediately upon fusion, which changes the membrane potential within the oocyte. The outside of the egg becomes negatively charged (Na+ influx), and no more sperm can bind.
What are the two slow block reactions? Describe.
Cortical, zona reaction. After the first sperm enters, there is a calcium influx. This causes enzymes from cortical granules to release and harden the zona pellucida.
Completion of the egg’s meiosis II is triggered by the same _____ _______that triggers the ______ reaction. This results in the formation of a ________.
Calcium influx, cortical, zygote.
What are pronuclei?
Pronuclei are the nuclei of sperm and egg after fertilization but before they fuse.
The zygote spends ____ days travelling to the uterus through movement of ______ and _________ contraction.
4-6, cilia, peristaltic.
What is the histological difference between a morula and a blastocyst?
A morula is a solid ball of identical cells, while a blastocyst has a fluid-filled cavity and distinct cell layers.
During the morula stage, inner cells develop _______ and communicate through ________ _______.
Polarity, gap junctions
By the 64-cell stage, cells have differentiated into _____ or ________. What is a trophoblast?
Embryonic, extraembryonic. Outer cell player of a blastocyst.
Prior to binding to the ________, the blastocyst must _____, including thinning of the _____ ________.
Endometrium, hatch, zona pellucida.
With the zona pellucida gone upon implantation, what can the blastocyst do? (2)
- contact the endometrium
- growth is not physically constrained
Implantation occurs in which 3 phases?
Apposition, adhesion, penetration/invasion
During apposition, the blastocyst makes contact with the _______. It is mediated by ______, _______, and ___________.
Endometrium, trophinin, IL-1, epidermal growth factor
During adhesion, the ________ firmly attaches to the _______. This is mediated by _______ and _______.
Blastocyst, endometrium, selectins, integrins
After implantation, the endometrium is called the ______. What are the three layers?
Decidua. Decidua basalis, decidua capsularis, decidua parietalis.
After implantation, the trophoblast differentiates into which 2 layers?
Syncytiotrophoblast, cytotrophoblast
