Question 1

Syndactyly is due to abnormal patterns of _______________.

Accepted Answer

A) Cell death 
B) Hox gene expression 
C) Sonic hedgehog signaling 
D) Myoblast migration from the somites 
E) Fibroblast growth factors-2, -4, and -8 signaling from the apical ectodermal ridge 
A) Cell death 
B) Hox gene expression 
C) Sonic hedgehog signaling 
D) Myoblast migration from the somites 
E) Fibroblast growth factors-2, -4, and -8 signaling from the apical ectodermal ridge A

Question 2

Which anomaly is due to the absence of programmed cell death?

Accepted Answer

A) Triphalangeal thumb 
B) Phocomelia 
C) Polydactyly 
D) Syndactyly 
E) Diplopodia 
A) Triphalangeal thumb 
B) Phocomelia 
C) Polydactyly 
D) Syndactyly 
E) Diplopodia D

Question 3

Which molecule is involved in fixation of the dorsoventral axis of the limb bud?

Accepted Answer

A) Sonic hedgehog 
B) Wnt-7a 
C) Fibroblast growth factor-2 
D) Hoxd-13 
E) Retinoic acid 
A) Sonic hedgehog 
B) Wnt-7a 
C) Fibroblast growth factor-2 
D) Hoxd-13 
E) Retinoic acid B

Question 4

What is a principal function of the apical ectodermal ridge?

Accepted Answer

A) Stimulating outgrowth of the limb bud 
B) Setting up the anteroposterior axis of the limb bud 
C) Determining the organ-specific characteristics of the ectodermal appendages of the limb 
D) Determining the pattern of neural ingrowth in the limb 
E) Attracting the subcutaneous plexus of capillaries 
A) Stimulating outgrowth of the limb bud 
B) Setting up the anteroposterior axis of the limb bud 
C) Determining the organ-specific characteristics of the ectodermal appendages of the limb 
D) Determining the pattern of neural ingrowth in the limb 
E) Attracting the subcutaneous plexus of capillaries

Question 5

Which of the following limb defects can be predicted by observing an early limb bud possessing two apical ectodermal ridges?

Accepted Answer

A) Syndactyly 
B) Radial hemimelia 
C) Diplopodia 
D) Phocomelia 
E) None of the above 
A) Syndactyly 
B) Radial hemimelia 
C) Diplopodia 
D) Phocomelia 
E) None of the above

Question 6

In the initiation of limb development,the expression and secretion of ____________ by local mesodermal cells stimulate the overlying ectoderm to secrete fibroblast growth factor-8.

Accepted Answer

A) Sonic hedgehog 
B) Fibroblast growth factor-10 
C) Bone morphogenetic protein-7 
D) Msx-1 
E) None of the above 
A) Sonic hedgehog 
B) Fibroblast growth factor-10 
C) Bone morphogenetic protein-7 
D) Msx-1 
E) None of the above

Question 7

Myoblasts migrating away from the somite toward the limb buds express _____________.

Accepted Answer

A) Pax-3 
B) Sonic hedgehog 
C) Paraxis 
D) All of the above 
E) None of the above 
A) Pax-3 
B) Sonic hedgehog 
C) Paraxis 
D) All of the above 
E) None of the above

Question 8

If the neighboring somites are removed,what would be missing from the developing limb?

Accepted Answer

A) Cartilage 
B) Skeletal muscle 
C) Bone 
D) Digits 
E) Melanocytes 
A) Cartilage 
B) Skeletal muscle 
C) Bone 
D) Digits 
E) Melanocytes

Question 9

A mutation of Hoxa-13 is characterized by ______________.

Accepted Answer

A) Diplopia 
B) Shortened phalanges 
C) Syndactyly 
D) Triphalangeal thumb 
E) Amelia 
A) Diplopia 
B) Shortened phalanges 
C) Syndactyly 
D) Triphalangeal thumb 
E) Amelia

Question 10

The skeletal musculature of the limb arises from the _________________.

Accepted Answer

A) Somatopleure of the lateral plate mesoderm 
B) Neural crest 
C) Splanchnopleure of the lateral plate mesoderm 
D) Neural tube 
E) Somites 
A) Somatopleure of the lateral plate mesoderm 
B) Neural crest 
C) Splanchnopleure of the lateral plate mesoderm 
D) Neural tube 
E) Somites

Question 11

___________,produced by the apical ectodermal ridge,stimulates outgrowth of the limb bud.

Accepted Answer

A) Sonic hedgehog 
B) Bone morphogenetic protein-7 
C) Fibroblast growth factor-4 
D) Wnt-7a 
E) None of the above 
A) Sonic hedgehog 
B) Bone morphogenetic protein-7 
C) Fibroblast growth factor-4 
D) Wnt-7a 
E) None of the above

Question 12

The apical ectodermal ridge forms at the boundary between regions expressing ________________.

Accepted Answer

A) Wnt-7a and En-1 
B) Shh and Msx-1 
C) Wnt-7a and Shh 
D) En-1 and Msx-1 
E) Wnt-7a and Msx-1 
A) Wnt-7a and En-1 
B) Shh and Msx-1 
C) Wnt-7a and Shh 
D) En-1 and Msx-1 
E) Wnt-7a and Msx-1

Question 13

Syndactyly is due to a disturbance in what embryological mechanism?

Accepted Answer

A) Induction 
B) Programmed cell death 
C) Cell migration 
D) Failure of tube formation 
E) Failure to fuse 
A) Induction 
B) Programmed cell death 
C) Cell migration 
D) Failure of tube formation 
E) Failure to fuse

Question 14

Which of the following associations of tissues contributing to the limb is incorrect?

Accepted Answer

A) Somite - myoblasts 
B) Neural crest - pigment cells 
C) Neural tube - motor axons 
D) Splanchnopleure of the lateral plate - skeleton 
E) Neural crest - sensory axons and Schwann cells 
A) Somite - myoblasts 
B) Neural crest - pigment cells 
C) Neural tube - motor axons 
D) Splanchnopleure of the lateral plate - skeleton 
E) Neural crest - sensory axons and Schwann cells

Question 15

The connective tissue of the limb arises from ______________.

Accepted Answer

A) Paraxial mesoderm 
B) Intermediate mesoderm 
C) Somatic mesoderm 
D) Lateral mesoderm 
E) Neural crest 
A) Paraxial mesoderm 
B) Intermediate mesoderm 
C) Somatic mesoderm 
D) Lateral mesoderm 
E) Neural crest

Question 16

In the developing limb,the sonic hedgehog gene product is produced in the ______________.

Accepted Answer

A) Zone of polarizing activity 
B) Region of interdigital cell death 
C) Common muscle mass 
D) Apical ectodermal ridge 
E) Progress zone 
A) Zone of polarizing activity 
B) Region of interdigital cell death 
C) Common muscle mass 
D) Apical ectodermal ridge 
E) Progress zone

Question 17

Sonic hedgehog is a morphogenetically active protein secreted by the _____________.

Accepted Answer

A) Apical ectodermal ridge 
B) Nonridge ectoderm 
C) Zone of polarizing activity 
D) Limb cartilage 
E) Neural crest 
A) Apical ectodermal ridge 
B) Nonridge ectoderm 
C) Zone of polarizing activity 
D) Limb cartilage 
E) Neural crest

Syndactyly is due to abnormal patterns of _______________.

Which anomaly is due to the absence of programmed cell death?

Which molecule is involved in fixation of the dorsoventral axis of the limb bud?

What is a principal function of the apical ectodermal ridge?

Which of the following limb defects can be predicted by observing an early limb bud possessing two apical ectodermal ridges?

In the initiation of limb development,the expression and secretion of ____________ by local mesodermal cells stimulate the overlying ectoderm to secrete fibroblast growth factor-8.

Myoblasts migrating away from the somite toward the limb buds express _____________.

If the neighboring somites are removed,what would be missing from the developing limb?

A mutation of Hoxa-13 is characterized by ______________.

The skeletal musculature of the limb arises from the _________________.

___________,produced by the apical ectodermal ridge,stimulates outgrowth of the limb bud.

The apical ectodermal ridge forms at the boundary between regions expressing ________________.

Syndactyly is due to a disturbance in what embryological mechanism?

Which of the following associations of tissues contributing to the limb is incorrect?

The connective tissue of the limb arises from ______________.

In the developing limb,the sonic hedgehog gene product is produced in the ______________.

Sonic hedgehog is a morphogenetically active protein secreted by the _____________.

Getting Ready for Pregnancy

Transport of Gametes and Fertilization

Cleavage and Implantation

Molecular Basis for Embryonic Development

Formation of Germ Layers and Early Derivatives

Establishment of the Basic Embryonic Body Plan

Placenta and Extraembryonic Membranes

Developmental Disorders: Causes, mechanisms, and Patterns

Integumentary, skeletal, and Muscular Systems

Nervous System

Neural Crest

Sense Organs

Head and Neck

Digestive and Respiratory Systems and Body Cavities

Urogenital System

Cardiovascular System

Fetal Period and Birth

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Exam 10: Limb Development

Syndactyly is due to abnormal patterns of _______________.

Which anomaly is due to the absence of programmed cell death?

Which molecule is involved in fixation of the dorsoventral axis of the limb bud?

What is a principal function of the apical ectodermal ridge?

Which of the following limb defects can be predicted by observing an early limb bud possessing two apical ectodermal ridges?

In the initiation of limb development,the expression and secretion of ____________ by local mesodermal cells stimulate the overlying ectoderm to secrete fibroblast growth factor-8.

Myoblasts migrating away from the somite toward the limb buds express _____________.

If the neighboring somites are removed,what would be missing from the developing limb?

A mutation of Hoxa-13 is characterized by ______________.

The skeletal musculature of the limb arises from the _________________.

___________,produced by the apical ectodermal ridge,stimulates outgrowth of the limb bud.

The apical ectodermal ridge forms at the boundary between regions expressing ________________.

Syndactyly is due to a disturbance in what embryological mechanism?

Which of the following associations of tissues contributing to the limb is incorrect?

The connective tissue of the limb arises from ______________.

In the developing limb,the sonic hedgehog gene product is produced in the ______________.

Sonic hedgehog is a morphogenetically active protein secreted by the _____________.

Getting Ready for Pregnancy

Transport of Gametes and Fertilization

Cleavage and Implantation

Molecular Basis for Embryonic Development

Formation of Germ Layers and Early Derivatives

Establishment of the Basic Embryonic Body Plan

Placenta and Extraembryonic Membranes

Developmental Disorders: Causes, mechanisms, and Patterns

Integumentary, skeletal, and Muscular Systems

Nervous System

Neural Crest

Sense Organs

Head and Neck

Digestive and Respiratory Systems and Body Cavities

Urogenital System

Cardiovascular System

Fetal Period and Birth

Filters