A&P 2 Lecture Chapter 29 Homework

The process that results in the formation of different cell types occurring through selective changes in genetic activity that causes some genes to be turned off, while others are turned on is called __________.

differentiation

Polyspermy results in

a nonfunctional zygote

During amphimixis,

the male and female pronuclei fuse

The site where fertilization normally occurs is in the

outer one-third of the uterine tube

The layer of follicle cells that surround the unfertilized egg is called the

corona radiata

The cell that directly results from the fusion of a secondary oocyte and a single sperm is called a(n)

zygote

Sperm release ________ to break down the bonds between adjacent follicle cells surrounding the oocyte.

hyaluronidase

Which of these pairs of terms is mismatched?

second trimester - embryogenesis

third trimester - largest size gain

first trimester - placentation

first trimester - formation of trachea and lungs

second trimester - embryogenesis

During the ________ trimester organs and organ systems complete most of their development and the fetus looks human.

second

After fertilization, the first cell division is completed

about 30 hours later

The process of cell division that divides the cytoplasm of the zygote among blastomeres is called

cleavage

The penetration of the endometrium by the blastocyst is referred to as

implantation

________ are nearly identical cells that are produced by early cleavages.

blastomeres

A space opens within the inner cell mass that will form the

amniotic cavity

During gastrulation,

three germ layers are formed

The region known as the primitive streak is the site of

migration of ectodermal cells to form the mesoderm

Which embryonic germ layer forms the linings of the respiratory and digestive tracts?

endoderm

Which embryonic germ layer forms the brain and spinal cord?

ectoderm

In ________, implantation occurs somewhere other than in the uterus.

ectopic pregnancy

The ________ is formed by the allantois, blood vessels, and yolk sac.

umbilical cord

The embryo becomes a fetus at

the end of the eighth week

The primary nutrient source for early embryonic development that later becomes an important site for blood formation is the

yolk sac

Embryonic secretion of ________ maintains the ________.

human chorionic gonadotropin; corpus luteum

Stretching of the cervix causes an increase in the blood levels of

oxytocin

Uterine contractions that are irregular and brief that occur toward the end of gestation are called

Braxton-Hicks

Twins that occur when blastomeres separate are called

monozygotic

________ is the medical specialty that focuses on postnatal development from infancy to adolescence.

Pediatrics

A patient comes in the clinic expressing concern over changes in her body. She says she has been experiencing axillary and genital hair growth, breast growth, acne and she is going through a growth spurt. You reassure her these are all a normal part of maturation and inform her that she has begun

puberty

The alternate forms of any one gene are called

alleles

If an individual carries a pair of alleles that are the same, the individual is ________ for the trait.

homozygous

If an individual carries two different alleles for the same trait, the individual is ________ for the trait.

heterozygous

The presence of a recessive gene can be detected (seen) only if the individual is

homozygous recessive

In polygenic inheritance, phenotypic characters are

determined by interactions among several genes

In ________, a sample of amniotic fluid is removed and the fetal cells it contains are analyzed.

amniocentesis

An individual's karyotype shows trisomy 21. This is an example of a

chromosomal abnormality