Once all organs system are present during gestation, the conceptus is then called a ________

fetus

Name the transport process by which oxygen, carbon dioxide, and nutrients cross the placenta

diffusion

List the names of the three primary germ layers

ectoderm

endoderm

mesoderm

Define implantation

attachment of blastocyst to lining of uterus

A single-celled, fertilized egg is known as a _____

zygote

The ______ is a disc shaped organ embedded in the uterine wall. It provides nutrition to the fetus via the umbilical cord

placenta

The period from fertilization through the 12th week is known as the _____

first trimester

Placental nutrition reaches the developing conceptus via a tube of blood vessels called the _____ _____

umbilical cord

The _____ and the ______ are two features of the fetal circulation that allow blood to bypass the non-functional lungs

ductus arteriosus and foramen ovale

Name the outermost germ layer

ectoderm

Name the stages of developing organism that occur during the preembryonic stage

zygote

cleavage

morula

blastocyst

All of the body's tissues originate from the tissues called ______

primary germ layers

List some structures that arise from the endoderm

digestive glands, epithelium of the digestive tract, and parathyroid gland

List the functions of amniotic fluid

protect fetus from temperature fluctuations

protect fetus from trauma

allow development of the lungs

The ______ performs respiratory, excretory, nutritional, endocrine, and immune functions of the fetus

placenta

At the placenta, maternal blood is found within structures called _____ and fetal blood is found within

placental sinuses; chorionic villi

The stage of _____ is complete when the blastomeres form three primary germ layers

embryogenesis

List some structures that arise from the ectoderm

central nervous system, salivary glands, epidermis

The ____ ______ arises from cells of the hypoblast. It contributes to the formation of the digestive tract and is the site of production of the first blood cells

yolk sac

The _____ is the germ layer that will form the inner layer of the digestive tract

endoderm

Indicate some of the structures that arise from the mesoderm

gonads, skeletal muscle, dermis

In the developing fetus, blood from the umbilical vein bypasses the liver and empties directly into the vena cava by way of a vessel called the ductus ______

venosus

Fertilization occurs in the ______ of the female reproductive tract

distal one-third of the uterine tube

The chorionic ______ are shaggy outgrowths of the chorion; they are involved in functioning of the placenta

villi

Daughter cells formed by cell division following fertilization are called _____

blastomeres

Name the sac that encloses both the embryo and a fluid-filled space

amnion

Indicate circulatory changes that occur just after birth

foramen ovale is closed by flaps in left atrium

ductus arteriousus collapses

The normal gestation period for a single (non-twin) baby is _____ weeks

40

The ____ are the organelles that contain genetic information, one from the sperm and one from the egg. These are present following fertilization but before mixing of sperm and egg chromosomes.

pronuclei

Approximately 6 days after ejaculation, sperm are

no longer viable

Indicate the three major processes that occur during the preembryonic stage of gestation

implantation, cleavage, embryogenesis

Describe a morula

stage of conceptus development when it is a spherical structure with 16 or more cells

Summarize the events of the second trimester

organs complete most development

The process of _____ is the differentiation of the primary germ layers into organ and organ systems

organogenesis

The ____ is the outermost embryonic membrane that encloses all of the other membranes and the embryo

chorion

Name the term for cell division that occurs in the earliest stages of zygote development

cleavage

Name the narrow space between embryoblast (inner cell mass) and the trophoblast during early embryogenesis

amniotic cavity

The _____ stage begins 16 days post conception, after the three germ layers have developed

embryonic