Ch. 11 Book Questions

Question 1

What molecule produced by the notochord is instrumental in inducing the floor plate of the neural tube?

a. Hoxa-5
b. Retinoic acid
c. Pax-3
d. Msx-1
e. Shh

Answer 1

e. Shh

Question 2

The cell bodies of the motor neurons of a spinal nerve arise from the:

a. Basal plate
b. Marginal zone
c. Floor plate
d. Roof plate
e. Alar plate

Answer 2

a. Basal plate

Question 3

An infant with a tuft of hair over the lumbar region of the vertebral column undergoes surgery for a congenital anomaly in that region. During surgery, it was found that the dura and arachnoid layers over the spinal cord were complete, but that the neural arches of several vertebrae were missing. What condition did the infant have?

a. Meningocele
b. Meningomyelocele
c. Encephalocele
d. Spina bifida occulta
e. Rachischisis

Answer 3

d. Spina bifida occulta

Question 4

Growth cones adhere strongly to a substrate containing:

a. Acetylcholine
b. Laminin
c. Epinephrine
d. Norepinephrine
e. Sonic hedgehog

Answer 4

b. Laminin

Question 5

Complete failure of the neural tube to close in the region of the spinal cord is:

a. Spina bifida occulta
b. Meningocele
c. Cranioschisis
d. Rachischisis
e. Myelomeningocele

Answer 5

d. Rachischisis

Question 6

Rhombomeres are segmental divisions of the:

a. Forebrain
b. Midbrain
c. Hindbrain
d. Spinal cord
e. None of the above

Answer 6

c. Hindbrain

Question 7

Pregnant women typically first become aware of fetal movements during what month of pregnancy?

a. Second
b. Third
c. Fourth
d. Sixth
e. Eighth

Answer 7

c. Fourth

Question 8

Rathke’s pouch arises from the:

a. Diencephalon
b. Stomodeal ectoderm
c. Mesencephalon
d. Pharyngeal endoderm
e. Infundibulum

Answer 8

b. Stomodeal ectoderm

Question 9

In the early days after birth, an infant does not pass fecal material and develops abdominal swelling. An anal opening is present. What is the probable condition?

Answer 9

Congenital megacolon (Hirschsprung’s disease), in which a segment of large intestine develops without parasympathetic ganglia. Intestinal contents cannot actively move through such an aganglionic segment.

Question 10

What is the likely appearance of the spinal cord and brachial nerves in an infant who was born with the congenital absence of one arm (amelia)?

Answer 10

The nerves would be hypoplastic (much smaller than normal), and the spinal cord would be thinner than normal in the area from which the nerves supplying the affected limb arise. The likely cause is excessive neuronal cell death because of the absence of an end organ for many of the axons that normally supply the limb.