b. Functions in Pregnancy. A female's breasts enlarge after the second
months of pregnancy. At the same time, the nipples become darker due to an increase
in pigmentation. For the first three days after the infant's birth, the breasts produce a
thin, yellowish fluid called colostrum. This fluid is not as nutritious as breast milk, but it
serves to nourish the infant until the mother's breast milk comes in on the third or fourth
PATHWAY OF AN OVUM
The descriptions and functions of the female reproductive organs have been
given. Here is the pathway of an ovum from an ovary to the uterus (figure 1-2).
a. On a monthly alternating basis, each ovary produces a mature ovum (egg).
b. Ova are located in spaces in the ovary called follicles.
c. An ovum matures and bursts out of the ovarian follicle into the appropriate
d. If the ovum is not fertilized, it is discharged from the body in a process called
menstruation. The lining of the uterus disintegrates in response to decreased levels of
estrogen and progesterone in the blood.
e. If the ovum is fertilized, it becomes implanted in the uterus where the egg
goes through a series of cell divisions. Growth and development of the ovum in the
uterus through the embryo and fetus phases eventually results in childbirth.
Figure 1-2. Pathway of an ovum.