4. Bones and Cartilages of the Human Body Figure 6.1

8. Bone Markings Table 6.1 Bulges, depressions, and holes that serve as: Sites of attachment for muscles, ligaments, and tendons Joint surfaces Conduits for blood vessels and nerves

9. Structure of Long Bone Figure 6.3 Compact bone – dense outer layer Spongy bone – honeycomb of trabeculae filled with red bone marrow

20. Stages of Endochondral Ossification Figure 6.8 Formation of bone collar around hyaline cartilage model. Hyaline cartilage Cavitation of the hyaline carti- lage within the cartilage model. Invasion of internal cavities by the periosteal bud and spongy bone formation. Formation of the medullary cavity as ossification continues; appearance of sec- ondary ossification centers in the epiphy- ses in preparation for stage 5. Ossification of the epiphyses; when completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages. Deteriorating cartilage matrix Epiphyseal blood vessel Spongy bone formation Epiphyseal plate cartilage Secondary ossificaton center Blood vessel of periosteal bud Medullary cavity Articular cartilage Spongy bone Primary ossification center Bone collar 1 2 3 4 5

27. Hormonal Control of Blood Ca Figure 6.11 PTH; calcitonin secreted Calcitonin stimulates calcium salt deposit in bone Parathyroid glands release parathyroid hormone (PTH) Thyroid gland Thyroid gland Parathyroid glands Osteoclasts degrade bone matrix and release Ca 2+ into blood Falling blood Ca 2+ levels Rising blood Ca 2+ levels Calcium homeostasis of blood: 9–11 mg/100 ml PTH Imbalance Imbalance

29. Response to Mechanical Stress Figure 6.12