REproduction

FSH and (1) _______ stimulate cells outside the zona pellucida to secrete (2) _____. A(n) estrogen-containing fluid accumulates in the follicle, and estrogen levels in the blood begin to increase. About eight to ten hours before being released from the ovary, the (3) _____ completes Meiosis I. And then its (4) _____ divides, forming two cells.
One cell, the (5) ____ _____, ends up with nearly all the cytoplasm. The other cell is the first of three (6) _____ ______. The meiotic parceling of the chromosomes among all four cells gives the secondary oocyte a (7) ______ chromosome number - which is the exact number required for gametes and for (8) ____ reproduction.
About halfway through the menstrual cycle, the (9) _____ gland detects the rise in the blood level of estrogens. It responds with a brief outpouring of (10) _____. This (10) surge causes rapid vascular changes that make the (11) ____ swell quickly. The surge also induces (12) __________ to digest the bulging follicle wall. The weakened wall ruptures. Fluid escapes and carries the (13) ______ ______ with it. Thus, the midcycle surge of LH triggers (14) _____ - the release of a secondary oocyte from an ovary.
The estrogens released early in the menstrual cycle also help pave the way for a possible (15) _______. Estrogens stimulate growth of the (16) _____ and its glands. Just before the midcyle surge of LH, follicle cells start to secrete some (17) _____, as well as estrogens. Blood vessels grow rapidly in the thickened endometrium. At ovulation, the estrogens act on tissue around the (18) ________ canal. The cervix starts to secrete large quantities of a thin, clear (19) ______, which is an ideal medium for sperm to swim through.
A. secondary oocyte
B. pregnancy
C. ovulation
D. oocyte
E. LH
F. cervical
G. estrogens
H. mucus
I. endometrium
J. sexual
K. cytoplasm
L. progesterone
M. enzymes
N. follicle
O. haploid
P. polar bodies
Q. pituitary