REproduction

An immature egg (oocyte) is released from one (1) ____ of a pair. From each ovary, and (2) _____ forms a channel for transport of the immature egg to the (3) ______, a hollow, pear-shaped organ where the embryo grows and develops. The lower narrowed part of the uterus is the (4) _______. The uterus has a thick layer of smooth muscle, the (5) _____, lined inside with connective tissue, glands, and blood vessels; this lining is called the (6) _______. The (7) _____, a muscular tube, extends from the cervix to the body surface; this tube receives sperm and functions as part of the birth canal. At the body surface are external genitals (vulva) that include organs for sexual stimulation. Outermost is a pair of fat-padded skin folds, the (8) ____ _____. Those folds enclose a smaller pair or skin folds, the (9) _____ ______. The smaller folds partly enclose the (10) _______, an organ responsive to sexual stimulation. The location of the (11) ___________ is about midway between the clitoris and vaginal opening.
(12) ________ occurs in the ovaries so that a normal female infant has about 2 million primary oocytes, with the division process halted in the meiosis I stage. By age seven, only about (13) ______ remain. A primary oocyte surrounded by a nourishing layer of granulosa cells is called a(n) (14) ______. When a female enters puberty, at the start of a menstrual cycle, the (15) ______ secretes a hormone (GnRH) in amounts that cause the (16) ______ pituitary to step up its secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The blood concentration of these two hormones increases and is carried by the blood to all parts of the body. That increase causes the (17) _____ to grow. The (18) _____ begins to increase in size, and more layers of cells form around it. (19) ____ deposits accumulate between the oocyte and the layers. In time, all the deposits form the (20) _______ _______, a noncellular coating around the oocyte.
A. oocyte
B. vagina
C. follicle
D. ovary
E. cervix
F. zona pellucida
G. clitoris
H. 300,000
I. anterior
J. oviduct
K. labia majora
L. endometrium
M. glycoprotein
N. myometrium
O. labia minora
P. urethra
Q. hypothalamus
R. meiosis
S. uterus