Chapter 6

Question 1

The sclerotome arises from cells that were located in the:
A. Notochord
B. Paraxial mesoderm
C. Intermediate mesoderm
D. Lateral plate mesoderm
E. None of the above

Answer 1

B. Paraxial mesoderm

Question 2

The cardiogenic plate arises from:
A. Embryonic endoderm
B. Somatic mesoderm
C. Splanchnic mesoderm
D. Intermediate mesoderm
E. Neural crest

Answer 2

C. Splanchnic mesoderm

Question 3

An inductive stimulus from which structure stimulates the transformation of the epithelial sclerotome into secondary mesenchyme?

Answer 3

E. Notochord

Question 4

Which of these structures in the embryo is unsegemented?
A. Somitomeres
B. Neuromeres 
C. Notochord
D. Somites

Answer 4

C. Notochord

Question 5

The intermediate mesoderm is the precursor of the:
A. Urogenital system 
B. Heart 
C. Somites 
D. Body Hall 
E. Vertebral bodies

Answer 5

A. Urogenital system

Question 6

What forces are involved in the folding of the neural plate to form the neural tube?

Answer 6

A change in cell shape at the median hinge point and
pressures of the lateral ectoderm acting to push up the
lateral walls of the neural plate.

Question 7

What role do neuromeres play in the formation of the CNS?

Answer 7

Neuromeres provide the fundamental organization of parts of the brain in which they are present. Certain homeobox genes are expressed in a definite sequence along the neuromeres.

Question 8

From what structures do the cells that form skeletal muscles arise?

Answer 8

The somites. Axial muscles form from cells derived from
the medial halves of the somites, and limb muscles arise
from cellular precursors located in the lateral halves of the
somites.

Question 9

Where do the first blood cells of the embryo form?

Answer 9

In blood islands that arise from mesoderm of the wall of

the yolk sac.