Joints develop alongside the bones they connect. Their formation begins in the embryo, where mesenchyme gives rise to bone, cartilage, and connective tissue. This lesson explains how skull joints and limb synovial joints form through different developmental pathways.
Mesenchyme is embryonic tissue that can develop into bones, cartilages, and connective tissues. In the skull, the route taken by developing bones depends on their location.
All flashcards
What is mesenchyme?
Embryonic tissue that can develop into bones, cartilage, and connective tissues.
How does intramembranous ossification form bone?
Mesenchymal cells differentiate into bone-producing cells, which form bone directly without first making a cartilage model.
What are fontanelles, and what do they become?
Fontanelles are initially wide, connective tissue-filled gaps between developing skull bones. As the bones grow, the gaps narrow into fibrous connective tissue joints called sutures.
What occurs in the joint interzone during synovial joint development?
The interzone forms between adjacent cartilage models. Cells at its center die to create the joint cavity, while surrounding mesenchyme contributes to the articular capsule and supporting ligaments.
Which cartilage remains after birth, and what are its roles?
Hyaline cartilage remains at the epiphyseal plates to permit bone lengthening during childhood and adolescence, and as articular cartilage covering bone surfaces at synovial joints.
Quiz questions
How do the bones forming the top and sides of the skull develop?Answer: They form directly from mesenchyme through intramembranous ossification.
When do limb buds first appear on the sides of the embryo?Answer: Near the end of the fourth week.
What begins to form within growing limb buds from about the sixth week?Answer: Hyaline cartilage models of future bones.
At approximately what point in embryonic development does ossification of limb cartilage models begin?Answer: Around the twelfth week.
What does mesenchyme around a developing synovial joint cavity contribute to?Answer: The articular capsule and supporting ligaments.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.