Fertilization, Pregnancy, Parturition, Lactation Flashcards
What are the 4 stages of pregnancy?
initiation
gestation
parturition
lactation
In this phase of pregnancy, the following occurs:
- fertilization
- implantation
- HCG rescue of corpus luteum
Initiation
What is the site of fertilization?
oviduct
At what portion of the oviduct does fertilization typically occur
upper third
When must fertilization occur in referance to ovulation?
within 24 hours of ovulation
How long can sperm survive in the female reproductive tract?
5 days
The following help what reach the oviduct?
- contraction of myometrium
- contraction of oviduct smooth muscle
- Allurin release by mature eggs
sperm migration
this is a chemoattractant for sperm to reach the egg in the ampulla of the oviduct…
allurin
What percent of sperm reach the fertilization site, and in what timeframe?
0.001% within 30-60 minutes
What percent of sperm make it to the uterus?
0.1 %
This occurs when sperm pass through the female reproductive tract. It causes alteration of the surface characteristics of sperm
Capacitation
sperm motility in the cervical canal requires a _____ pH
alkaline
Secretions from what gland in the male reproductive tract elevate the pH?
prostate gland
This hormone makes cervical mucous watery, facilitating sperm motility
estrogen
_______, present in the ejaculate, promotes myometrial contractions
prostaglandins
sperm acquire the ability to fertilize eggs through what process?
capacitation
Sperm capacitation involves what three processes?
cholesterol withdrawal
redistribution of surface proteins
calcium influx
The calcium influx in sperm capacitation has what effect?
increases motility
capacitated sperm can penetrate the ______ and contact the _______ to undergo acrosome reaction
penetrate corona radiata
contact zona pellucida
what does the fertilizing sperm use in order to penetrate the corona radiata?
plasma membrane bound enzymes
the plasma membrane on the head of the sperm binds to which proteins on the zona pellucida?
ZP3 proteins
What triggers the acrosome reaction which allows hydrolytic enzymes to be released onto the zona pellucida?
binding of acrosome to the ZP3 receptors
When the sperm reaches the ovum, what happens?
plasma membrane fusion, DNA injection to the ovum cytoplasm
ZP3 proteins are inactivated and proteins harden the zona pellucida when enzymes from the cortical granules are released. This prevents…
polyspermy (multiple fertilization)
what enzyme is released from the acrosome which allows penetration of the zona pellucida?
acrosin
sperm fusion to the ovum membrane is mediated by ____ on the sperm head and ______ on the ovum membrane
fertilin on sperm
integrin receptor on ovum
This reaction is called…
release of cortical granules containing enzymes for ZP3 degradation and hardening of glycoproteins on zona pellucida…
zona reaction
The zona reaction prevents…
polyspermy
the zona reaction triggers what two events?
- completion of 2nd meiotic division
2. extrusion of 2nd polar body
this process is the formation of the female nucleus and the male pronucleus…
fusion
The fertilized ovum divides via…
mitosis
Within a week, the fertilized ovum differntiates into a ____ which is capable of implantation
blastocyst
Blastocyst impants on endometrial lining via…
enzymes that digest endometrium
Days 20-24 of a regular 28 day cycle are optimal for implantation due to…
progesterone action
When is hCG detectable in maternal serum?
after implantation, 8-11 days after conception
What hormone rescues the corpus luteum?
placental hCG
The placenta is well established and operational how long after implantation?
5 weeks
The placenta performs the functions of what three systems for the fetus?
digestive, respiratory, renal
the placenta acts as a transient endocrine organ that secretes what three pregnancy hormones?
hCG
Estrogen
Progesterone
What two hormones released from the placenta are essential for maintaining a normal pregnancy?
estrogen, progesterone
This hormone released by the placenta maintains the corpus luteum until placenta takes over function in the last two trimesters…
hCG
hCG levels in maternal plasma peak between…
9 and 12 weeks
What allows hCG levels to decline and corpus luteum to regress?
placental secretion of estrogen and progesterone
This hormone has the same actions as LH, stimulates corpus luteum secretion of progesterone and estrogen
hCG
The placenta converts maternal cholesterole to what precursor hormone of progesterone and estriol?
pregenolone
Progenolone in the is taken up by the fetus, where id is converted to _____ by what gland?
converted to DHEA-sulfate by adrenal gland