ChatGPT Generated
No description yet. This curated deck is ready for daily study.
Card preview (24)
What are the three divisions of intraembryonic mesoderm?
• Paraxial mesoderm • Intermediate mesoderm • Lateral plate mesoderm These divisions play crucial roles in the development of various structures in the embryo.
What structure forms in the midline where mesoderm does NOT develop?
The notochord The notochord is essential for the development of the neural tube.
What is the role of the notochord?
Stimulates neural tube formation The notochord is a key signaling center during early embryonic development.
When do somites begin forming?
End of the 3rd week Somites are segmented structures that give rise to various tissues.
How many pairs of somites initially form?
40 pairs These somites will differentiate into various structures in the body.
Somites divide into which two regions?
• Ventromedial → Sclerotome (SHH mediated) • Dorsolateral → Dermomyotome (Wnt mediated) This division is crucial for the development of the vertebral column and muscles.
What does the sclerotome form?
Vertebrae, ribs, axial skeleton The sclerotome is responsible for forming the bony structures of the spine.
What does the dermatome form?
Dermis of the skin The dermatome contributes to the skin’s connective tissue.
What does the myotome form?
Skeletal muscles The myotome is responsible for the development of voluntary muscles.
What signaling molecule induces sclerotome differentiation?
Sonic Hedgehog (SHH) SHH is crucial for the patterning of the somites.
What is resegmentation?
Fusion of caudal half of one somite with cranial half of the next to form a vertebra This process is important for the proper alignment of vertebrae.
Why are there 8 cervical nerves but 7 cervical vertebrae?
Due to resegmentation; C1 cranial half fuses with occipital bone This anatomical feature is important for understanding spinal nerve distribution.
What forms the nucleus pulposus?
Notochord remnants The nucleus pulposus is the inner core of intervertebral discs.
What forms the annulus fibrosus?
Somite (somitocele) cells The annulus fibrosus is the outer ring of intervertebral discs.
Remnants of the notochord can form what tumor?
Chordoma Chordomas are rare tumors that can occur along the spine.
What are the two types of ossification?
• Endochondral • Intramembranous These processes are essential for bone development.
Endochondral ossification requires what first?
Cartilage model This model serves as a precursor for bone formation.
Intramembranous ossification forms bone directly from what?
Mesenchyme This type of ossification is responsible for forming flat bones.
Which bones form by intramembranous ossification?
• Skull vault • Face bones • Clavicle These bones develop directly from mesenchymal tissue.
Which gene is essential for bone formation?
Runx2 Runx2 is a key transcription factor in osteoblast differentiation.
The skull is divided into what two major parts?
• Neurocranium • Viscerocranium These parts serve different functions in protecting the brain and supporting facial structures.
What cells contribute to the viscerocranium?
Neural crest cells Neural crest cells are crucial for the development of facial structures.
What are fontanelles?
Wide connective tissue regions where sutures meet Fontanelles allow for growth and flexibility of the skull during birth.
When does the posterior fontanelle close?
1–2 months This closure is part of normal cranial development.