a&p 2 module 28
The individual cells produced by cleavage are called
blastomeres
The stage of labor during which the fetus emerges from the vagina is called the ________ stage.
expulsion
Embryonic and early fetal development occurs in the ________ trimester.
first
The period of gestation when the rudiments of all major organ systems are established is the ________ trimester.
first
If an individual carries a pair of alleles that are the same, the individual is ________ for the trait.
homozygous
In pregnancy, expansion of the uterus results from
hypertrophy of smooth muscle cells
The mesoderm forms
muscle
Which hormone stimulates the milk let-down reflex?
oxytocin
The traits of an individual controlled by his or her genotype are his or her
phenotype
The placenta is expelled from the uterus during the ________ stage of labor
placental
The hormone that increases the flexibility of the pubic symphysis during pregnancy is
relaxin
Deoxygenated blood is carried to the placenta by the
umbilical arteries.
A person's original chromosomes and their component genes constitute that person's
genotype
________ is the time spent in growing within the uterus.
gestation
If an individual carries two different alleles for the same trait, the individual is ________ for the trait.
heterozygous
A zygote whose genotype is XY will develop as a
male
Which of the following does not occur during the first trimester?
organs become functional
Stretching of the cervix causes an increase in the blood levels of
oxytocin
During gestation, contraction of the myometrium is inhibited by ________, produced by the placenta.
progesterone
The placenta is not a source of which of the following hormones?
prolactin
During amphimixis,
the male and female pronuclei fuse.
The period of gestation that is characterized by the largest fetal weight gain and fat deposition is the ________ trimester.
third
During gastrulation,
three germ layers are formed
Oxygenated blood is carried away from the placenta by the
umbilical vein
The embryonic heart starts beating as blood begins to flow through chorionic vessels at approximately ________ of development.
week 3
The various forms of any one gene are called
alleles
The extra-embryonic membrane that forms the fetal portion of the placenta is the
chorion
In polygenic inheritance, phenotypic characters are
determined by interactions among several genes.
The gradual modification of anatomical structures during the period from conception to maturity is
development.
The first stage of labor is the ________ stage.
dilation
Which of the following hormones is the cause of most puberty-related changes in a female?
estrogen
The infancy stage of life is considered to be over when the baby reaches ________ of age.
1 year
All of the following occur during pregnancy except
a woman's bladder capacity increases.
The developmental period heralded by the onset of puberty is known as
adolescence.
How many chromosomes do human somatic cells contain?
46
________ is the time spent in growing within the uterus.
Gestation
All of the following occur at puberty except
GnRH levels decline
Molly is homozygous for the dominant black hair trait. Therefore,
Molly has black hair
