Fundamentals of Anatomy and Physiology

472 Chapter 19

Lumen of uterus

Chorion

Germ Ectoderm

layers Mesoderm

Endoderm

Yolk sac

of embryo

Uterine wall

Amnion

Amniotic cavity

Connecting stalk

Chorionic villi

(^) ®
Learning
Cengage ©
Figure 19- 12 The early developmental stages of the embryo showing germ layers, chorionic villi, and other structures.
Common Disease, Disorder, or Condition
Breast Cancer
Breast cancer, which occurs most often in females, is a leading cause of death in
women. However, men can also get breast cancer. One in every eight women will
develop this serious, often fatal disease. Symptoms of this disease include lumps,
leakage, or puckering of the nipple and changes in skin texture of the breast. Early
detection is crucial to survive this cancer. Women should perform self-examinations on
a regular basis. The American Cancer Society recommends that women have mam-
mograms done every 2 years between 40 and 49 years old and once a year thereafter.^
Mammography uses low-intensity X-rays to detect tumors in the soft tissues of the
breast. This procedure detects tumors less than 1 cm that are too small to be detected
by self-examination. If a tumor is detected, a biopsy is performed to deter-mine whether
it is malignant or benign. Fortunately, most tumors of the mammary glands are benign.
However, those that are malignant can spread to other parts of the body and eventually
lead to death. Yet early detection of breast cancer can lead to effective treatment and
survival.
on in development, the umbilical cord will become the
structure that will allow the exchange of nutrients and
wastes between the mother and the fetus.
As pregnancy progresses, the uterus enlarges to ac-
commodate the developing fetus. It eventually pushes up
into the abdominal cavity and occupies most of
this area. The abdominal organs push against the dia-
phragm muscle, causing the ribs to expand and the tho-rax
to widen. During this time the center of gravity of the
mother moves, resulting in an accentuated curvature of the
lumbar vertebrae called lordosis, which may cause
backaches. At this time, it is essential for the mother to