After you have studied this chapter, you should be able to:
Distinguish between growth and development. (p. 876)
Distinguish between prenatal and postnatal. (p. 876)
Describe fertilization. (p. 876)
23.3 Prenatal Period
List and provide details of the major events of cleavage. (p. 879)
Describe implantation. (p. 882)
Discuss the hormonal and other changes in the maternal body during
pregnancy. (p. 883)
Explain how the primary germ layers originate, and list the structures
each layer produces. (p. 885)
Describe the major events of the embryonic stage of development.
Describe the formation and function of the placenta. (p. 888)
and describe the major events of the fetal stage of devel-
opment. (p. 892)
Trace the path of blood through the fetal cardiovascular system. (p. 897)
Explain the role of hormones in the birth process and milk production.
23.4 Postnatal Period
Name the postnatal stages of development of a human, and indicate
the general characteristics of each stage. (p. 904)
Describe the major cardiovascular and physiological adjustments in
the newborn. (p. 905)
Distinguish between passive and active aging. (p. 909)
Contrast life span and life expectancy. (p. 911)
ois—tubelike structure extending from
the yolk sac into the connecting stalk of an embryo.
n—outermost membrane surrounding the
fetus and its membranes.
age—period of development when a
zygote divides, producing increasingly smaller cells.
oderm—outermost germ layer of embryo.
a—space between the chorionic villi that F
with maternal blood.
ne hair covering the fetus.
oderm—middle germ layer of embryo.
a—embryonic structure consisting of a
solid ball of about sixteen cells that resembles a mulberry.
to be born: pre
al—period of development before birth.
onatal—period of development including the
rst four weeks after birth.
natal—period of development after birth.
natal—period of development before birth.
escence—process of growing old.
oblast—cellular layer that surrounds the
inner cell mass and helps nourish it.
ical cord—structure attached to the fetal
navel (umbilicus) that connects the fetus to the placenta.
“Higher multiples” such
as quadruplets face
health risks, but twins
usually do very well.