HUMAN BIOLOGY

326 Chapter 16

asked to sign a contract that spells out legal rights and

obligations of the parties.

Once a potential donor is accepted, she undergoes several

weeks of physiological preparation. hormone treatments

stop her normal ovarian cycling. then, injections of fertility

drugs “hyperstimulate” her ovaries to produce as many

as fifty or sixty oocytes. Common side effects include hot

flashes, bloating, and mood swings. When tests indicate

that numerous follicles are ready to rupture, a final injection

promotes ovulation. released oocytes are retrieved via minor

surgery. If any oocytes are missed, a sexually active donor

may become pregnant with one or more embryos.

Some experts are concerned that hyperstimulating a

woman’s ovaries may lead to reduced future fertility and an

increased chance of developing ovarian cancer. these worries

are among the reasons why many states limit the number of

times a given woman can donate her eggs.

ExplorEon Your own

STDs. Table 16.5 in Section 16.10 lists the seven most prevalent STDs globally. To explore how these

health concerns are affecting your community or state, go online and find out if your local or state

public health department maintains statistics on STDs. Which are the most prevalent STDs in your

area? Have the numbers been rising or declining? If someone thinks they may have been exposed,

what resources are available for confidential testing?

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FOCUS ON hUmaN impaCt

Eggs for ArT

a young, healthy woman can earn thousands of dollars

by providing oocytes for use by fertility clinics. recipients

typically are couples or individuals who cannot (or choose

not to) conceive on their own.

egg “donation” is a demanding process. advance

screening usually includes providing details about one’s

personal life, education,

StD history, and lifestyle.

the woman’s medical

history, and often those of

close blood relatives, will

be scrutinized for possible

genetic disorders. DNa and

IQ testing and an in-depth

psychological evaluation all

may be required. In most

states a donor also will be

SummArY

Section 16.1 Ovaries, which produce

eggs, are a female’s primary reproductive

organs. Oviducts and other ducts and

accessory glands are also part of the female

reproductive system. Oviducts open into the

uterus, which is lined by the endometrium.

Unless a fertilized egg begins to grow in the uterus, the

endometrium proliferates, then is shed in the three-phase

menstrual cycle.

Section 16.2 The menstrual cycle

overlaps with an ovarian cycle. At the end of

each menstrual period, a follicle (containing

an oocyte) matures in an ovary. Hormones

trigger rebuilding of the endometrium.

A midcycle peak of LH triggers ovulation, the release of a

secondary oocyte (egg) from the ovary.

A corpus luteum that forms from what remains of the

follicle secretes progesterone that prepares the endometrium

to receive a fertilized egg and helps maintain the endo-

metrium during pregnancy. When no egg is fertilized, the

16.13

Gschmeissner/Science Source

Oocyte in a developing follicle

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