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