Chapter 3 - embryology

Question 1

Which structure in embryogenesis is comprised of the zygote and its associated membranes?
a. Morula.
b. Blastula.
c. Conceptus.
d. Endoderm.

Answer 1

c - Conceptus.

Question 2

You look into a microscope to view a developing embryo, 3 days after conception. You see a clump of 15-20 cells, that are a single solid mass. This structure is in the:

a. Morula stage of embryogenesis.
b. Fertilization stage of embryogenesis.
c. Conceptus stage of embryogenesis.
d. Blastula stage of embryogenesis.

Answer 2

Morula - develops in 3 days after conception, where it makes a solid mass of 16 cells that float freely in the uterus.

Question 3

A embryologist is investigating why a population of women in a rural city in China are experiencing miscarriages at disproportionate rates. The researcher discovers that the embryo’s in these women cannot develop past a 100 cell, fluid filled, mass. At which stage in embryonic development is the cell aborting?

a. Conceptus.
b. Trophoblast.
c. Morula.
d. Blastocyst.

Answer 3

d - bastocyst.

Question 4

What are the two cell types in the blastocyst?

Answer 4

1. Inner mast cell - develops into baby.
2. Trophoblasts in the shell - develops into the placenta and chroionic sac.

Question 5

A spontaneous gene mutation occurs soon after fertilization of an ovum. This mutation silences genes for trophoblast production. Which of the following will be heavily impacted by this mutation?

a. Organogenesis.
b. Neurulation.
c. Placental formation.
d. All of the above.

Answer 5

d - All of the above - because without trophoblasts the cell cannot develop into a blastocyst and will spontaneosly abort in the morula stage.