BIOL 129 Lecture Notes - Lecture 4: Intramembranous Ossification, Endochondral Ossification, Pelvic Inlet
Document Summary
Ossification: formation of bone, there are two types (1) intramembranous: within a membrane . Embryonic connective tissue transforms into highly vascular membrane of soft tissue. Development of cranial bones in skull (2) endochondral: within cartilage . Bone arises from cartilage model in roughly the shape of bone to come. * clavicles, mandibles, and facial bones form by a combination of the two methods. Growth occurs at epiphyseal plate: zone of cartilage in metaphysis (between epiphysis and diaphysis) Cartilage cells (chondrocytes) are produced on epiphyseal side and pushed towards diaphysis. Cartilage is replaced by bone on diaphyseal side of plate. Cartilage cells stop dividing and bone replaces cartilage. Resting zone: anchors growth plate to bone on epiphysis. During childhood: hgh (human growth hormone) produced by pituitary gland and thyroxine produced by the thyroid gland. Estrogen in females and androgens in males stimulate osteoblasts (this happens first in females)
