22. What is the primary function of the periosteum? A. Cushioning joints B. Covering articular surfaces C. Nourishing bones D. Producing red blood cells E. Storing fat 23. The term "cranial"is synonymous with which directional term? A. Inferior B. Superior C. Anterior D. Posterior E. Lateral 24.Which bone type is characterized by its ability to reduce friction and protect tendons? A. Long Bones B. Short Bones C. Flat Bones D. Irregular Bones E. Sesamoid Bones 25. The thoracic cavity is separated from the abdominopelvic cavity by which structure? A. Peritoneum B. Pleura C. Diaphragm D Rib Cage E. Mediastinum 26. Which movement involves turning the palm of the hand downward? A. Supination B . Pronation C. Rotation D. Circumduction E. Protraction 27. What is the primary function of osteoclasts in bone remodeling? A. Bone formation B. Bone resorption C. Calcium storage D. Hematopoiesis E. Cartilage development

## Step1<br />The primary function of the periosteum is to nourish the bone. It is a membrane that covers the outer surface of all bones, except for the joints of long bones. The periosteum consists of an outer fibrous layer and an inner osteogenic layer. The osteogenic layer contains osteoblasts and osteoclasts, which are responsible for bone formation and resorption, respectively. The periosteum also serves as an attachment point for tendons and ligaments.<br /><br />## Step2<br />The term "cranial" is synonymous with the directional term "superior". In anatomical terminology, "superior" refers to a position above or higher than another part of the body. The cranium is the part of the skull that encloses the brain, so "cranial" pertains to the head or brain.<br /><br />## Step3<br />Sesamoid bones are characterized by their ability to reduce friction and protect tendons. The most well-known sesamoid bone is the patella (kneecap). Sesamoid bones are typically small, round, and embedded in tendons. They are formed in response to strain and are found in locations where a tendon passes over a joint.<br /><br />## Step4<br />The thoracic cavity is separated from the abdominopelvic cavity by the diaphragm. The diaphragm is a dome-shaped muscle that plays a crucial role in respiration. It contracts and relaxes to allow air into the lungs and expel it out. The diaphragm is the primary muscle responsible for breathing and separates the thoracic cavity from the abdominopelvic cavity.<br /><br />## Step5<br />The movement that involves turning the palm of the hand downward is called pronation. In anatomical terms, pronation refers to the rotation of the forearm or foot so that the palm or sole is turned downward or posteriorly. It is the opposite of supination, which is the rotation of the forearm or foot so that the palm or sole is turned upward or anteriorly.<br /><br />## Step6<br />The primary function of osteoclasts in bone remodeling is bone resorption. Osteoclasts are large, multinucleated cells that are responsible for the breakdown and resorption of bone tissue. They secrete acids and enzymes that dissolve the mineral matrix and collagen fibers of the bone. This process is essential for the maintenance, repair, and remodeling of bones. Osteoclasts work in conjunction with osteoblasts, which are responsible for bone formation.