c. DNA errors accumulate.
d. Lipid breakdown in aging membranes releases
e. Free radical damage escalates.
2. Active aging
a. In autoimmunity, the immune system attacks the
b. Apoptosis is a form of programmed cell death. It
occurs throughout life, shaping organs.
3. The human life span
a. The theoretical maximum life span is 120 years.
b. Life expectancy, based on real populations, is 75.4
years for men and 83.2 years for women in the
United States, and may be lower in poorer nations
and those ravaged by AIDS.
c. Medical technology makes life expectancy more
closely approach life span.
7. The end of life
a. Certain signs may appear in sequence when a
person dies of a chronic illness.
b. Preactive dying takes up to three months. The
person withdraws socially and appetite wanes.
c. Active dying takes up to two weeks. The person
rests, may become confused or agitated, and eats
very little. Gradually the organ systems shut down.
The skin becomes mottled as circulation slows and
congestion and loud breathing occur.
AGING (PAGE 909)
1. Passive aging
a. Passive aging entails breakdown of structures and
slowing or failure of functions.
b. Connective tissue breaks down.
_____________ is an increase in the size of the individual,
whereas ___________ is the continuous process by which
an individual changes from one phase to another. (p. 876)
_____________ is the period of development from
fertilization to birth, whereas _________________ is the
period of development from birth to death. (p. 876)
Describe how sperm cells move in the female
reproductive tract. (p. 876)
Summarize the events occurring after the sperm cell head
enters the oocyte’s cytoplasm. (p. 878)
23.3 Prenatal Period
Describe the process of cleavage. (p. 879)
Distinguish between a morula and a blastocyst. (p. 880)
Describe the formation of the inner cell mass, and explain
cance. (p. 880)
Explain what happens when the blastocyst nestles into
the endometrium. (p. 882)
List the functions of hGG. (p. 882)
Describe the formation of the placenta, and explain its
functions. (p. 882)
Explain the hormonal changes that occur in the maternal
body during pregnancy. (p. 884)
Describe the nonhormonal changes that occur in the
maternal body during pregnancy. (p. 885)
Explain how the primary germ layers form. (p. 885)
List the structures derived from the primitive tissues of
the ectoderm, mesoderm, and endoderm. (p. 885)
Distinguish between the chorion and amnion. (p. 888)
Explain the function of the amniotic ±
uid. (p. 888)
Describe the formation of the umbilical cord. (p. 891)
Explain how the yolk sac and the allantois are related, and
list the functions of each. (p. 891)
Explain why the embryonic period is so critical. (p. 892)
Give the time frame for the fetus, listing the major
changes that occur during fetal development. (p. 892)
Describe a full-term fetus. (p. 893)
Explain how the fetal cardiovascular system is adapted to
intrauterine life. (p. 895)
Compare the properties of fetal hemoglobin with those
of adult hemoglobin. (p. 897)
Trace the pathway of blood from the placenta to the fetus
and back to the placenta. (p. 897)
Describe the role of progesterone in initiating the birth
process. (p. 899)
Discuss the events that occur during the birth process. (p. 899)
Explain positive feedback and the role of hormones in the
expulsion of the fetus and the afterbirth. (p. 900)
Detail the roles of prolactin and oxytocin in milk
production and secretion. (p. 902)
23.4 Postnatal Period
Distinguish between a newborn and an infant. (p. 904)
Explain why a newborn’s F
rst breath must be particularly
forceful. (p. 905)
List some of the factors that stimulate the F
rst breath. (p. 905)
Explain why newborns tend to develop water and
electrolyte imbalances. (p. 905)
Discuss the cardiovascular changes in the newborn. (p. 905)
Describe the characteristics of an infant. (p. 905)
Distinguish between a child and an adolescent. (p. 906)
List some of the degenerative changes that begin during
adulthood. (p. 907)
List some of the factors that promote senescence. (p. 907)
Contrast preactive dying and active dying. (p. 908)
Discuss the signs of passive and active aging and the
physiological causes of these signs.
_________________ is the length of time a human can
theoretically live, whereas _____________ is the realistic
projection of how long an individual will live.