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27 Cards in this Set
- Front
- Back
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What are the 5 steps of fertilization?
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1. Contact between sperm / ovum
2. Acrosomal Reaction 3. Growth of Acrosomal Process 4. Fusion of Plasma Membranes 5. Entry of sperm nucleus |
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What begins in response to the LH surge?
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Resumption of meiosis within the ovarian follicle
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In what stage is the ooctye arrested in after ovulation?
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Metaphase II
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What is the large layer of cells surrounding the egg?
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Cumulus Oophoros
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Where does fertilization occur?
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Fallopian Tube
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What is the normal life of an egg?
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18-24 hours
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Sperm maturation begins where?
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Within the epididymis
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What is gradually developed truing the sperms transit through the epididymis?
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Motility
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What is the transit time for sperm in the human epididymis?
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80-90 days
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What is sperm capacitation, where does it occur?
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Sperm gaining the "capacity" to fertilize egg
Occurs within female reproductive tract |
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What is the main change seen in sperm capcitation?
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Increased cAMP levels results in development of hyperactivated motility
(characteristic of capacitated sperm) |
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How does the sperm penetrate the cumulus oophorus?
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Via a cell surface hyaluronidase, PH20
Assisted by sperm motility |
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What is the main signaling event that allows fusion of sperm with egg?
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Calcium cascade within sperm which allows for initiation of acrosome reaction
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Penetration of the Zona Pellucida requires with 2 items?
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1. Motile Force generated by flagellar movement
2. Enzymatic Hydrolysis by acrosomal proteases |
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Do both the tail and the head of the sperm enter the egg?
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NO, only the head
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Calcium release is triggered by what?
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Phospholipase C activity
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When does egg activation occur and what does it involve?
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Occurs after fertilization and involves the completion of the second meiotic division and initiates embryonic development
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What part of egg activation blocks polyspermy?
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Exocytosis of cortical granules
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What does it mean in >2 pronuclei are seen in the fertilized egg?
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Has been fertilized by >1 sperm
Inviable |
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Where is the block to polyspermy in humans?
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Both a membrane block AND ZP block
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Does oocyte activation require sperm entry?
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NO, can be induced artificially
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What % of sperm are actually viable?
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4% (not sure if correct)
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What technique can be used to enhance fertilization?
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Intrauterine insemination
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How do doctors known when to inject/perform intrauterine insemination?
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Women use LH dipstick to monitor LH surge indicating ovulation
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For completely amotile sperm, what procedure can be performed?
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Intracytoplasmic sperm injection (ICSI)
remove cumulus cells and directly inject sperm into ovum |
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What condition is characterized by round headed sperm that lack an acrosome?
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Globozoospermia
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From where can sperm be extracted from for ICSI?
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Both epidymal and testicular sperm
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