Neuromuscular Embryology: Mesoderm Development and Gastrulation

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What is the primary function of the notochord during embryonic development?

To signal other developmental processes (correct)

To contribute to the formation of the gonads and kidneys

To form the spinal cord

To give rise to the somites

Which germ layer gives rise to the blood, heart, kidneys, gonads, bones, muscles, and connective tissues?

Ectoderm

Endoderm

All three germ layers contribute to these tissues

Mesoderm (correct)

What is the process by which the mesoderm is formed during gastrulation?

Delamination of cells from the ectoderm

Invagination and ingression of cells from the top layer (correct)

Differentiation of cells within the existing mesoderm

Evagination of cells from the endoderm

What is the significance of the somites in embryonic development?

They give rise to the skeletal muscles, cartilage, tendons, and dermis of the back Signup and view all the answers

How are the somites formed during embryonic development?

They are formed from the mesoderm in a cranio-caudal direction Signup and view all the answers

What is the significance of the neural tube formation during embryonic development?

It gives rise to the spinal cord Signup and view all the answers

Which germ layer is responsible for the formation of the ectoderm and endoderm during gastrulation?

The primitive streak Signup and view all the answers

What is the role of the intermediate mesoderm in embryonic development?

It contributes to the formation of the gonads and kidneys Signup and view all the answers

How does the fate of the mesoderm cells depend on their location within the primitive streak?

The fate of the mesoderm cells is determined by where they migrate through the primitive streak Signup and view all the answers

What is the primary function of the ectoderm during embryonic development?

To form the neural tube and spinal cord Signup and view all the answers

What is the primary role of the sclerotome during vertebral development?

To form the vertebral bodies and neural arches Signup and view all the answers

How do the vertebrae develop from the sclerotome?

The caudal part of one sclerotome and the cranial portion of the next sclerotome form each vertebral body Signup and view all the answers

What is the role of the notochord during vertebral development?

The notochord forms the intervertebral discs Signup and view all the answers

What is the role of the myotomes during vertebral development?

The myotomes form the muscle attachments to the vertebrae Signup and view all the answers

What is the process by which the vertebrae form from the sclerotome?

Chondrification of the sclerotome mesenchyme Signup and view all the answers

What is the significance of the somites being 'synchronous with neurulation'?

The somites and neural tube develop at the same time Signup and view all the answers

What is the significance of the fact that 'when a somite has been transplanted it differentiates according to its original position'?

The somite cells have a fixed fate based on their position of origin Signup and view all the answers

What is the role of the ectoderm in the differentiation of the somites?

The ectoderm sends out 'gross factor signals' that the somite cells respond to Signup and view all the answers

What is the significance of the fact that 'somites appear every 90 minutes and look identical'?

The somites form at a regular, synchronized pace Signup and view all the answers

What is the significance of the fact that 'somites contain multipotent cells'?

The somite cells require signals from surrounding tissues to differentiate Signup and view all the answers

What is the primary role of the apical ectodermal ridge (AER) in limb bud development?

It signals for proximal-distal elongation of the limb bud Signup and view all the answers

What is the primary function of the progress zone in limb bud development?

It promotes proximal-distal elongation of the limb bud through cell proliferation Signup and view all the answers

Which signaling molecule is responsible for specifying digit identities along the anterior-posterior axis of the limb bud?

Sonic hedgehog (Shh) Signup and view all the answers

What is the primary cause of polydactyly (extra digits) in humans and animals?

Increased levels of Sonic hedgehog (Shh) signaling Signup and view all the answers

What is the primary mechanism responsible for the formation of joints and separation of digits during limb development?

Apoptosis (programmed cell death) Signup and view all the answers

What is the primary process responsible for the majority of fetal skeletal growth, including the development of vertebrae, ribs, and limbs?

Endochondral ossification Signup and view all the answers

What are the primary sources of signals that induce the formation of dorsal or ventral cell types in the developing spinal cord?

The notochord and floor plate for ventral cell types, and the roof plate for dorsal cell types Signup and view all the answers

What is the primary function of the alar and basal plates in the developing spinal cord?

They give rise to the dorsal and ventral horns of the spinal cord, respectively Signup and view all the answers

Which of the following statements is true regarding the dorsal-ventral patterning of the limb bud?

The ectoderm determines the dorsal-ventral patterning, and peeling off the ectoderm can lead to the formation of upside-down hands Signup and view all the answers

What is the primary cause of nail patella syndrome, a condition characterized by hypoplastic nails and the absence of patellae?

Mutations in regulatory genes controlling dorsal-ventral patterning Signup and view all the answers