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)
Spongy bone looks like a sponge hence the name and contains a lot of red bone marrow (medulla ossium rubra). Red bone marrow is what produces red blood cells. Compact bones which consists of medulla ossium flava or yellow bone marrow, is made mostly of fat cells (Openstax College, 2013).
2. Explain the relationship between calcium and bones. (1 point)
Calcium is essential for maintaining necessary level of bone mass to support structures of the body. The body uses calcium for heart, blood, muscles and nerves. It can be lost through bodily process like sweating, waste, shedding of hair, skin and fingernails. The close relationship between bone and calcium is the principal processes of calcium metabolism. Bone contains about 99% of calcium in the body and can behave as an adequate buffer for maintenance of a constant level of freely moving calcium in soft tissues, extracellular fluid and blood (Openstax College, 2013).
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)
Increased blood calcium levels stimulate the secretion of calcitonin from the thyroid and active osteoblasts to build bones thereby reducing blood calcium levels to within their normal range. Decreased blood calcium levels stimulate the parathyroid glands to release PTH which activate osteoclasts which degrade bone and release calcium into the blood stream thereby raising blood calcium levels.
4. Explain specifically how osteoporosis affects the bone matrix and the normal bone remodeling cycle. (1 point)
Osteoporosis results from an imbalance in which bone reabsorption outstrips bone formation. The net loss of bone matrix renders bones weaker and more susceptible