Chapter 2 Lectures 4-5 Flashcards
The principal energy source for ejaculated spermatozoa is:
A. Prostatic acid phosphatase
B. Internal glucose
C. Prostatic citric acid
D. Fructose in seminal vesicle fluid
E. Glycogen released from the vaginal epithelium
D. Fructose in seminal vesicle fluid
What is the principal hormonal stimulus for ovulation?
The sharp surge of luteinizing hormone produced by the anterior lobe of the pituitary gland.
What is capacitation?
A poorly understood interaction between a Spermatozoon and female reproductive tissues that increases the ability of the sperm to fertilize an egg.
In some mammals, capacitation is obligatory, but in humans the importance of capacitation is less well established.
Where does fertilization occur?
In the upper third of the uterine tube.
Name two functions of the ZP3 protein of the zone pellucida.
The ZP3 protein acts as a specific sperm receptor through its O-linked oligosaccharides; much of its polypeptide backbone must be exposed to stimulate the acrosomal reaction.
What is polyspermy and how is it prevented after a Spermatozoon enters the egg?
The fertilization of an egg by more than one Spermatozoon. It is prevented through the fast electrical block on the plasma membrane of the egg and by the later zona reaction, by which products released from the cortical granules act to inactivate the sperm receptors in the zona pellucida.
A woman gives birth to septuplets. What is the likely reason for the multiple births?
She had probably take clomiphene for the stimulation of ovulation. Natural septuplets are almost never seen.
When multiple oocytes obtained by laparoscopy are fertilized in vitro, why are up to three embryos implanted into the woman’s uterus, and why are the other embryos commonly frozen?
The introduction of more than one embryo into the tube of the woman is commonly done because the chance that any single implanted embryo will survive to the time of birth is quite small. The reasons for this are poorly understood. Extra embryos are frozen because if a pregnancy does not result from the first implantation, the frozen embryos can be implanted without the inconvenience and expense of obtaining new eggs from the mother and fertilizing them in vitro.
Why do some reproductive technology center insert spermatozoa under the zone pellucida or even directly into the oocyte?
In cases of incompatibility between the sperm and egg, poor sperm motility, or deficient sperm receptors in the zona, introducing the sperm directly into or near the egg can bypass a weak point in the reproductive sequences of events.
Of the barriers to sperm survival and tranpsort within the female reproductive tract, low pH is most important in the:
A. Upper uterine tube
B. Lower uterine tube
C. Uterine cavity
D. Cervix
E. Vagina
E. Vagina
