Ch 29. Development

What is the fate of the cluster of cells in the blastocyst known as the inner cell mass?

The cells will develop into the embryo.

state of full development or completed growth

maturity

A hollow ball of cells created by cleavage is called a

blastocyst

The chorion develops from the _____

mesoderm and trophoblast

Three layers of gastrulation

ectoderm, mesoderm, endoderm

Study of embryonic development

embryology

Pregnancy events from week 3-8 are called

embryonic development

The infusion of two haploid (n) gametes each containing 23 chromosomes

fertilization

Transfer of genetically determined characteristics from generation to generation

inheritance, heredity

During cleavage the single large zygote is converted into a __________.

multicellular embryo consisting of smaller cells called blastomeres

Where does fertilization take place?

near the junction between the ampulla and isthmus of the uterine tube

Provides cellular organelles, nourishment, and genetic programming

oocyte

Begins at birth and continues to maturity

postnatal development

The processes that occur in the first 2 weeks after fertilization, producing an embryo

pre-embryonic development

Modification of anatomical structures and physiological characteristics that occur before birth is referred to as

prenatal development

When rapid fetal growth and deposition of adipose tissue takes place

third trimester

The extra-embryonic membranes that develop from the endoderm and the mesoderm are the ______.

yolk sac and amnion

thick, glycoprotein-rich membrane secreted by oocyte, encapsulating it

zona pellucida

46 chromosomes

zygote

The sudden increase in the calcium ion level has important effects including

-exocytosis of vesicles adjacent to the oocyte membranes -completions of meiosis two -activation of enzymes that cause a rapid increase in the ovums metabolic rate

When does fertilization occur?

12-24 hours after ovulation

Out of the 200-500 million sperm cells that are released during an ejaculation, only ____ complete the short journey up the Fallopian tubes to where an egg is waiting to be fertilized.

about 10,000

Frees the enzymes contained in the acrosome of each sperm

acrosome reaction

senescence

aging

What is the extra embryonic membrane that gives rise to the urinary bladder

allantois

The combining of male and female chromosomes is called

amphimixis

The fusion of male and female pronuclei is termed ____.

amphimixis

Cleavage ends when

blastocyst contacts uterine wall

Prevents fertilization by more than one sperm

block to polyspermy

Glycoprotein layer of the sperm membrane is removed

capacitation

Which of the following forms the placenta

chorion

A sequence of cell divisions that begin after fertilization is called __________.

cleavage

A sequence of cell divisions that begins immediately after fertilization is called ___________.

cleavage

What is the correct sequence of events going from the zygotes to the fetus

cleavage, implantation, placentation, embryogenesis

Follicle cells that line the zona pellucida

corona radiata

Releases enzymes called zonal inhibiting proteins (ZIPs)

cortical reaction

The exocytosis of vesicles adjacent to the oocyte membrane is called the

cortical reaction

Begins at week 9 and continues until birth

fetal development

How many sperm reach the isthmus

fewer than 100

Period of pre-embryonic, embryonic, and early fetal development

first trimester

What is the "moment of conception"

fusion of the male and female pronuclei

What triggers the activation of the secondary oocyte

fusion of the sperm and secondary oocyte membranes

Study of mechanisms responsible for inheritance is called

genetics

The time spent in prenatal development is known as

gestation

Breaks down the bonds between adjacent follicle cells

hyaluronidase

Which of the following enzymes are released from the acrosome of sperm?

hyaluronidase and acrosin

Begins when the blastocyst attaches to the endometrium of the uterus

implantation

When development of fetal organs and organ systems takes place

second trimester

Delivers the paternal (fathers) chromosomes to the site of fertilization

sperm

The umbilical cord or umbilical stalk, contains _______

the allantois, blood vessels, and yolk stalk