Exam 3: The Tissue Level of Organization

Chemical, physical, or biological agents that can induce birth defects are called

The embryonic notochord gives rise to part of the intervertebral discs in the adult human.

Thalidomide, once used to alleviate morning sickness in pregnant women, resulted in

The embryonic ultimately form the arms and legs of the adult.

It is easy to remember that in humans, 3 weeks after fertilization, there are three germ layers.

In human embryos, the yolk sac is important because it

Briefly describe the formation of the nervous system.

A transverse section through the 24-day embryo, dorsal to ventral, would first contact the

The epiblast gives rise to the three primary germ layers.

Figure 3.1 Use the diagram above to answer the following questions. -Which letter indicates the blastocyst?

Name three primary germ layers in the embryo.

All major organs are present in rudimentary form.

Identical (monozygotic) twins are

Conjoined twins occur as a result of

What embryonic epiblast cells that remain on the surface of the trilaminar disc are ultimately called.

Another name for birth defect is

A(n) abortion is one in which the fetus dies and is naturally aborted.

If a mutation occurs in the hypoblast cells of a bilaminar embryo, one might expect birth defects to be present in the

The term bilaminar disc refers to the embryonic and .

Which of the following does not distinguish mesoderm from either endoderm or ectoderm?