The hormone oxytocin aids the birth process by stimulating
uterine wall contractions.
The chorion is the _____ and the amnion is the _____.
outermost covering of an embryo and helps form the placenta; a membrane that encircles a developing embryo
During the embryonic stage, the primary germ layers develop from the
embryonic disc.
The placenta allows
oxygen and nutrients to diffuse from maternal blood to the embryo.
The placenta is composed of tissues from the
mother and embryo.
The yolk sac
forms blood cells in early development
The major body parts derived from mesoderm are the
muscle tissue, bone tissue, and bone marrow.
Teratogens are substances that
cause congenital malformations.
The three leading causes of death in the United States are
heart disease, cancer, and stroke.
heart disease, cancer, and stroke
heart disease, cancer, and stroke.
The hormone measured in a pregnancy test is
hCG.
The external genitalia of the fetus can be distinguished as male or female by about ___ weeks after fertilization
12
Amniotic fluid
protects the embryo against being jarred by movements
Which of the following is not a function of the amniotic fluid
allows transport of nutrients to the embryo
The allantois
forms blood cells and gives rise to the umbilical arteries and vein.
A blastomere is a _____ and a blastocyst is _____.
cell produced by cleavage; a hollow ball of cells
The term newborn refers to the period from birth through _____, whereas the term infant refers to the period from _____.
the first four weeks; the first month to 1 year
The hormones that maintain the uterine wall during the last 5 to 6 months of pregnancy are
placental estrogen and progesterone.
The major body part(s) derived from ectoderm is/are
nervous system and skin
The major body parts derived from endoderm are the epithelial lining of the
all of the above (respiratory tract, urinary bladder, digestive tract.
Labor is regulated by
positive feedback control.