Exam 3 Review Questions Flashcards
The morphology of specific muscles within the limb bud is determined by which of the following factors?
Surrounding connective tissue
BMPs
Apical Ectodermal ridge
Noggin
Surrounding Connective Tissue
Pre-muscles in the developing limb bud are derived from which of the following sources?
Lateral plate mesoderm
Somitic dermatomes
Somiti myotomes
Neural crest
Somiti Myotomes
Which of the following represents the principal function of the AER?
Stimulating outgrowth of the limb bud
Setting up the AP axis of the limb bud
Determining the specific characteristics of the ectodermal appendages of the limb
Determining the pattern of neural outgrowth of the limb
Stimulating outgrowth of the limb bud
If the limb disc of a salamander embryo is rotated 180 degrees, so that both the AP and the DV axes are reversed, which of the following would be observed?
The resulting limb would be completely normal with no reversal of axes.
The AP axis of the resulting limb would be reversed but not the DV axis
The DV axis of the resulting limb would be reversed but not the AP axis
Both the AP and the DV axes of the resulting limb would be reversed
The AP axis of the resulting limb would be reversed but not the DV axis
Numerous experiments have shown that retinoic acid is capable of inducing the formation of the posterior limb in vertebrates. Retinoic acid is not the actual morphogen but is capable of activating which of the following genes, which is thought to express the actual morphogen?
Sonic Hedgehog
Wnt-7 gene
Pax-3 gene
Noggin gene
Sonic Hedgehog
Pattern formation along the proximodistal axis of the limb bud is primarily determined by which of the following?
Paxa gene
Hoxd gene
Retinoic acid
Sonic Hedgehog
HoxD Gene
The presence of webbing between the toes of wading birds such as ducks and the presence of webbed fingers (syndactyly) is most likely associated with which of the following?
Overexpression of Noggin
Oligohydramnios
Reduced apoptotic activity
Amniocentesis
Reduced apoptotic activity
Which of the following experiments carried out on salamander embryos illustrates that the developing limb is a highly regulative system?
Split limb primordium into two halves and prevent them from fusing
Juxtapose two equivalent halves of a limb primordium
Remove part of a limb primordium
All of the above
All of the above
Which of the following factors functions as the initial initiator of future hindlimb development?
Hoxd
Tbx4
Shh
Gli3
Tbx4- Note that Tbx5 is for the future forelimb
In limb development, the attraction of the outgrowing nerves to peripheral organs seems to be unspecific to a very high degree. Connections between a nerve and the end organ can be made only if the two correspond to each other. These assumptions are based on which of the following experiments?
An eye was transplanted to the side of a salamander embryo after the forelimb rudiment was removed.
A salamander forelimb bud was removed and replaced by a hindlimb bud.
A salamander limb rudiment was transplanted to the flank (side) of a host salamander.
An obstacle (ex. Piece of mica) was placed between the spinal cord and the region where the hindlimb rudiment was to develop in a salamander embryo.
An eye was transplanted to the side of a salamander embryo after the forelimb rudiment was removed.
During limb development, pre-muscle cells in the somite express c-met, which is the receptor for which of the following?
Pax-3
N-cadherin
Tcf-4
Scatter Factor
Scatter Factor
In the formation of limb joints, which of the following signal molecules is responsible for inhibiting BMP in the region of the future joint cavity?
Shh
Noggin
Wnt-1
Eng-1
Noggin
Which of the following occurs when an additional limb bud is transplanted into the immediate vicinity of the host forelimb of a salamander embryo?
Neither limb bud will be supplied by any branches of the brachial plexus.
The brachial nerves will develop branches running out to the additional limb and will supply it.
The transplanted limb bud will be supplied by local nerves that would normally supply flank muscles.
Local brachial plexus nerves deviate from the normal limb bud and supply only the transplanted limb bud.
The brachial nerves will develop branches running out to the additional limb and will supply it.
The formation of clubfoot (talipes equinovarus) is associated with which of the following?
A misplaced ZPA Defective cellular migration from somites Thalidomide Oligohydramnios A neural crest defect
Oligohydramnios
Which of the following is observed when the forelimb rudiment of a salamander embryo is removed so that the limb fails to develop?
The associated spinal ganglia increases to more than 150% of their normal size.
Local nerves are not affected.
The nerves of the brachial plexus remain smaller (thinner) than they would have been if the limb were still there.
Nerves of the future brachial plexus undergo apoptosis
The nerves of the brachial plexus remain smaller (thinner) than they would have been if the limb were still there.
Which of the following are NOT derived from neural crest cells?
Postganglionic autonomic neurons
Autonomic ganglia
Sensory neuron cell bodies
Motor neuron cell bodies
Motor neuron cell bodies
Trunk Neural Crest cells utilize three migratory pathways. The earliest (first) emigrating cells follow which of the following pathways?
Ventral Path
Cranial neural crest cells from the region of the rhombomeres 6 and 7 are involved in the establishment which of the following structures?
Pharyngeal Arch 3
Neural crest cells that give rise to the leaflets of the semilunar valves, thymus, thyroid, and parathyroid glands, and the septa that divide the conus arteriosus into the aortic and pulmonary arteries arise from which of the following?
Cardiac neural crest
Which of the following neurocristopathies is characterized by pigmentation defects, white strip in the hair, deafness, and cleft palate among others?
Waardenburg Syndrome
A low concentration of which of the following factors results in placode formation, while a high concentration of the same factor results in the formation of the neural plate.
BMP
Which of the following factors is referred to as the “master gene of eye development” in Drosophila and in human eye development is necessary to induce the formation of the lens placode?
Pax-6
In the development of the retina, the nasal temporal (anterior-posterior) axis is fixed first (before the dorsoventral axis). This axis is established, in part, by gradients composed of which of the following?
Ephrins
Except for the pharyngeal arch musculature, the rest of the pharyngeal arch mesenchyme is derived from which of the following source?
Neural Crest
Except for the first pharyngeal pouch, patterning of the pharyngeal arch endoderm is heavily based on exposure to which of the following factors?
Retinoic Acid
Which of the following develops from the cartilaginous portion of the second pharyngeal arch?
Stapes
The palate forms during which of the following time periods?
6-10 weeks of development
Tendons of limb muscles arise from the lateral plate mesoderm. Limb muscles arise from which of the following sources?
Dorsal lip of myotome
Ventral buds of myotomes
Ventrolateral dermatomes
Paraxial somitomeres
Ventrolateral dermatomes
Which of these cell and tissue types arises from cranial, but not trunk, neural crest cells?
Sensory ganglia Adrenal medulla Melanocytes Schwann Cells None of these answers
None of these answers
Which of the following is a poor substrate for migrating neural crest cells?
Laminin Chondroitin sulfate Fibronectin Type IV Collagen Hyaluronic Acid
Chondroitin sulfate
Neural crest cells arise from which of the following?
Somite Dorsal non-neural ectoderm Neural plate Splanchnic mesoderm Yolk sac mesoderm
Neural plate
A 65 month old infant exhibits multiple congenital defects, including a cleft palate, deafness, ocular hypertelorism, and a white forelock but otherwise dark hair on his head. Which of the following represents the probable diagnosis?
CHARGE association Von Recklinghausen's disease Hirschsprung's disease Waardenburg syndrome None of the above
Waardenburg syndrome
Which of the following is involved in the migration of neural crest cells from neural tube?
Snail BMP-2 Mash-1 Norepinephrine Glial Growth Factor
Snail
Which is not a derivative of neural crest cells?
Sensory neurons Motor neurons Schwann cells Adrenal Medulla Dental Papilla
Motor neurons
What maintains the competence of neural cells to differentiate into autonomic neurons?
Shh Acetylcholine Mash-1 Glial Growth Factor TGF-Beta
Mash-1