Text Book Questions

Question 1

Satellite cells of muscle are activated under which of theses conditions?

Answer 1

All of the above:
Normal muscle fiber growth
Muscle fiber regeneration
Muscle fiber hypertrophy

Question 2

Which cellular component of the epidermis is a peripheral outpost of the immune system and functions to present antigens to other immune cells?

Answer 2

Langerhans’ cells

Question 3

Which structure is mesodermal in origin?

Answer 3

Arrector pili muscle

Question 4

Craniosynostosis is caused by an abnormal developmental course of the…?

Answer 4

Cranial sutures

Question 5

Which myogenic regulatory factor is expressed latest in the development of a muscle fiber?

Answer 5

MRF-4

Question 6

In the let-down of milk during lactation, the myoepithelial cells contract in response to…?

Answer 6

Oxytocin

Question 7

What component of developing skin determines the nature of hairs that form or the thickness of epidermis in fetus?

Answer 7

Dermis

Question 8

Why is cranial bone typically not found over an area where part of the brain is missing?

Answer 8

Brain tissue induces formation of surrounding membranous skeletal elements

Question 9

Which of the following molecules plays an important role in the determination of the dorsoventral axis of the developing limb?

Answer 9

Wnt-7a

Question 10

What molecule is associated with myogenic cells migrating into the limb bud from the somites?

Answer 10

Pax-3

Question 11

What is the principal function of the AER?

Answer 11

Stimulating outgrowth of the limb bud

Question 12

In the developing limb the shh gene product is produced in the…?

Answer 12

ZPA

Question 13

The connective tissue of the limb arises from the…?

Answer 13

Lateral mesoderm

Question 14

The formation of clubfoot is associated with…?

Answer 14

Oligohydramnios

Question 15

An infant whose mother underwent chorionic villus sampling during pregnancy was born with the tips of two digits missing. What is a possible cause?

Answer 15

Tear in amnion could have resulted in amnionic band wrapping around the tips of the digits

Question 16

A woman who underwent amniocentesis during pregnancy gave birth to a child with a duplicated thumb. What is a possible cause?

Answer 16

Genetic mutation:
Unlikely to be caused by the amniocentesis, because morphology of digits is well established by the time the procedure would take place

Question 17

If the somites close to a limb-forming region are experimentally removed, the limbs form without muscles. Why?

Answer 17

Muscle-forming cells arise form the somites

Question 18

A child is born with webbed fingers (syndactyly). What is the reason for this anomaly?

Answer 18

Absence of programmed cell death (apoptosis) in interdigital mesoderm