Development of the Musculoskeletal System
36 Questions
0 Views

Development of the Musculoskeletal System

Created by
@ConvincingFluorite

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What condition describes the complete absence of a limb?

  • Amelia (correct)
  • Ectrodactyly
  • Phocomelia
  • Meromelia

    • Which limb defect is characterized by the partial absence of a limb?

  • Polydactyly
  • Meromelia (correct)
  • Amelia
  • Brachydactyly

    • What is the primary cause of syndactyly?

  • Insufficient apoptotic cell death between digital rays (correct)
  • Excessive proliferation of mesoderm
  • Additional sites of apoptotic cell death
  • Development of abnormal AER

    • Ectrodactyly is often referred to as which of the following?

    <p>Missing digit</p> Signup and view all the answers

    Which condition is characterized by the presence of extra digits?

    <p>Polydactyly</p> Signup and view all the answers

    What is the role of the zone of polarizing activity (ZPA) in limb development?

    <p>To produce a signal that influences digit formation</p> Signup and view all the answers

    In which week do the first digital rays appear in the developing hand and foot?

    <p>Week 6</p> Signup and view all the answers

    Which statement accurately describes limb bone differentiation?

    <p>Limb bones form in a proximal to distal fashion</p> Signup and view all the answers

    How does limb rotation differ between the upper and lower limbs?

    <p>Upper limb rotates laterally and lower limb rotates medially</p> Signup and view all the answers

    What is the primary result of the rotation of the lower limb during development?

    <p>The pattern of innervation twists into a spiral</p> Signup and view all the answers

    Which of the following describes the mechanism of digit formation from digital rays?

    <p>Apoptotic cell death stimulates the growth of separate digits</p> Signup and view all the answers

    What is the primary cause of limb defects noted in clinical correlations?

    <p>Defects in the signaling from the apical ectodermal ridge</p> Signup and view all the answers

    What is the primary signal produced by the zone of polarizing activity (ZPA)?

    <p>Sonic hedgehog (SHH)</p> Signup and view all the answers

    What is the primary origin of the posterior skull and vertebral column?

    <p>Paraxial mesoderm (somites)</p> Signup and view all the answers

    Which structure differentiates into muscle and contributes to the dermis of the back?

    <p>Dermomyotome</p> Signup and view all the answers

    From which cells does the craniofacial skeleton develop?

    <p>Neural crest cells</p> Signup and view all the answers

    What is the segmental pattern of innervation in the adult derived from?

    <p>Each somite's growth of one spinal nerve</p> Signup and view all the answers

    What is formed by the ventro-medial cells of the somite?

    <p>Sclerotome</p> Signup and view all the answers

    Which part of the somite is associated with intrinsic bones and muscles of the back?

    <p>Epimere</p> Signup and view all the answers

    Which mesodermal structure gives rise to the sternum and appendicular skeleton?

    <p>Lateral plate mesoderm</p> Signup and view all the answers

    During somite differentiation, what signals the ventro-medial cells to become mesenchymal?

    <p>Notochord and floor plate of the neural tube</p> Signup and view all the answers

    Which of the following is the correct order of development from somites?

    <p>Epithelization, sclerotome, myotome, dermomyotome</p> Signup and view all the answers

    What does the hypomere develop into?

    <p>Muscles and connective tissue of the trunk and limbs</p> Signup and view all the answers

    What is the process by which sclerotome cells organize around the neural tube?

    <p>Resegmentation</p> Signup and view all the answers

    Which part of the sclerotome fuses with the cranial half of the adjacent sclerotome?

    <p>Caudal half</p> Signup and view all the answers

    What happens to the notochord during the formation of vertebrae?

    <p>It becomes the nucleus pulposus</p> Signup and view all the answers

    What is the cause of congenital scoliosis?

    <p>One half of a vertebra does not form</p> Signup and view all the answers

    Which condition results from incomplete resegmentation of sclerotomes?

    <p>Klippel-Feil syndrome</p> Signup and view all the answers

    Which embryonic structure gives rise to all skeletal muscle?

    <p>Somites</p> Signup and view all the answers

    What are the muscles derived from epimere called?

    <p>Epaxial muscles</p> Signup and view all the answers

    What is the primary event occurring during the limb bud development at week 4?

    <p>Upper limb bud appears</p> Signup and view all the answers

    What signals the overlying ectoderm to grow during limb bud development?

    <p>Fibroblast growth factor (FGF-10)</p> Signup and view all the answers

    Which domain contains only somite-derived cells?

    <p>Primaxial domain</p> Signup and view all the answers

    What condition is characterized by a depressed sternum?

    <p>Pectus excavatum</p> Signup and view all the answers

    Which of the following correctly describes the structure of ribs?

    <p>Ribs are made up of multiple embryonic primordia</p> Signup and view all the answers

    What is the effect of Lmx-1 expression in limb development?

    <p>Establishes dorsal-ventral axis</p> Signup and view all the answers

    Study Notes

    Introduction to Musculoskeletal Development

    • Objectives: Understand cell types from somites, development of axial and appendicular skeletons, and limb development.
    • Timeline: Development occurs around Week 5 (35-38 days into gestation).

    Origin of Skeletal Tissue

    • Paraxial Mesoderm: Forms posterior skull, vertebral column, and ribs.
    • Lateral Plate Mesoderm: Gives rise to sternum and appendicular skeleton.
    • Neural Crest Cells: Contribute to craniofacial skeleton.

    Somite Structure and Function

    • Somites: Segmental structures lateral to the neural tube that differentiate into various tissues.
    • Differentiation:
      • Ventro-medial cells become mesenchymal, forming sclerotome (tendons, ligaments, bones).
      • Dorso-lateral cells form dermomyotome (muscle, dermis).

    Innervation of Somites

    • Each somite correlates with one spinal nerve, leading to segmental innervation patterns for muscles and skin.
    • Divisions:
      • Epimere: Associated with dorsal rami, forming intrinsic back structures.
      • Hypomere: Associated with ventral rami, forming muscles/connective tissues of the trunk and limbs.

    Axial Skeleton Development

    • Vertebrae Resegmentation:
      • Sclerotome cells reorganize around the neural tube before they split and fuse to form vertebrae.
      • Original notochord transforms into nucleus pulposus.
    • Clinical Correlations:
      • Congenital Scoliosis: Results from hemivertebra formation due to partial vertebra development.
      • Klippel-Feil Syndrome: Incomplete resegmentation causes fused vertebrae, leading to a short neck, low hairline, and limited neck motion.

    Formation of Ribs and Sternum

    • Ribs: Develop from sclerotomes that form thoracic vertebrae with three embryonic structures (centrum, neural arch, costal process).
    • Sternum: Unique as it originates from parietal lateral plate mesoderm.

    Appendicular Skeleton Development

    • Limbs derive from parietal lateral plate mesoderm.
    • Skeletal Muscle Development:
      • Somites are the source of all skeletal muscle; epaxial (intrinsic back) and hypaxial (other skeletal muscle) classifications based on somite origin.

    Limb Bud Formation

    • Limb Buds: Upper limbs appear in Week 4, lower limbs in Week 5, consisting of ectodermal caps and mesodermal cores.
    • Apical Ectoderm Ridge (AER): Crucial for limb growth, directing mesoderm proliferation via signaling molecules (FGF-10 and FGF-8).

    Limb Axis and Differentiation

    • Proximal/Distal Axis: AER signals distal limb formation; dorsal/ventral axis differentiation involves homeobox genes like Lmx-1.
    • Cranial/Caudal Axis: Zone of Polarizing Activity (ZPA) directs digit positioning via Sonic hedgehog (SHH) signaling, contributing to varying digit lengths.

    Limb Bone Development

    • Differentiation: Limb bones arise from proximal to distal: humerus/femur (stylopod), radius/ulna/tibia/fibula (zeugopod), and carpals/metacarpals/phalanges/tarsals/metatarsals (autopod).
    • Ossification: Bones form through endochondral ossification, starting from a cartilage template.

    Digital Formation and Limb Rotation

    • Digital Rays: Form by apoptosis in the AER; complete separation of digits typically occurs by Week 8.
    • Rotation:
      • Upper limbs rotate laterally (extensor muscles lateral).
      • Lower limbs rotate medially (extensor muscles anterior).

    Limb Innervation

    • Dermatomes: Skin regions supplied by specific spinal nerves; limb rotation modifies original innervation patterns.
    • Motor Innervation: Reflects segmental development; includes specific mappings for upper limb muscle innervation.

    Clinical Correlations in Limb Development

    • Limb Defects:
      • Amelia: Complete limb absence.
      • Meromelia: Partial limb absence.
      • Phocomelia: Absence of long limb bones.
      • Brachydactyly: Shortened digits from inadequate proliferation.
      • Syndactyly: Fused digits from insufficient apoptosis.
      • Polydactyly: Extra digits resulting from additional apoptotic site development.
      • Ectrodactyly: Missing digits leading to cleft conditions.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Development_of_the_Musculoskeletal_System_Corrected.pptx

    Description

    Explore the intricate processes involved in the development of the musculoskeletal system, including somite-derived cells and their correlation to spinal nerves. Learn about the formation of axial and appendicular skeleton components as well as limb development from bud formation to digit maturation.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser