Case Study 3

Module 04 Case Study: Bone Tissue

Part I— “Marissa” Questions

1. Describe bone tissue and the role each component plays in bone physiology and remodeling. What is the difference between compact and spongy bone? (2 points) Bone tissue is found throughout the body and there are four types of bone tissue. These include osteocytes, osteoblasts, osteoclasts, and osteogenic. The osteoblasts is the bone cell responsible for creating new bone. Osteocytes are the cells that maintain mineral concentration of the matrix through secretion of enzymes. The osteogenic cells are the only bone cells able to divide. They are undifferentiated with high mitotic activity. Osteoclasts are the bone cells responsible for bone resorption or breakdown and are continuously breaking down old bone while osteoblasts are forming new bone. The balance between osteoblasts and osteoclasts is responsible for the reshaping of bone. Company bone is denser than spongy bone. It is found under the periosteum and in the diaphysis of long bone, where it provides support and protection. Compact bone can withstand compressive forces whereas spongy bone has open spaces and supports shifts in weight distribution. The spaces provide balance to the compact bone by making the bones lighter. The spaces in spongy bone also contain red marrow. Spongy bone contains osteocytes in the lacunae.

2. Explain the relationship between calcium and bones. (1 point) calcium makes the bones more dense and stronger

3. Explain how the body controls calcium levels in the bones and blood. Be sure to describe the roles of parathyroid hormone (PTH) and calcitonin in detail. (2 points) The parathyroid hormone (PTH), secreted by the parathyroid glands, is responsible for regulating blood calcium levels; it is released whenever blood calcium levels are low. Calcitonin, a hormone produced by the thyroid, acts in opposition to PTH by inhibiting osteoclasts, stimulating osteoblasts, and increasing excretion of calcium into...