Test: Skeletal System - 1 - MCAT MCQ

Osteoclasts are large, multinucleated cells that are responsible for bone resorption. They break down and remove old or damaged bone tissue, allowing for the remodeling and renewal of bone. Osteoblasts, on the other hand, are responsible for bone formation, while osteocytes are mature bone cells that help maintain bone tissue.

Ball and socket joints, such as the hip and shoulder joints, allow for the greatest range of motion among the different types of joints. These joints are formed by the rounded end of one bone fitting into a cup-like socket of another bone. The spherical shape of the joint allows for movement in multiple directions, including flexion, extension, abduction, adduction, and rotation.

The femur is the long bone in the thigh and is part of the appendicular skeleton, which includes the bones of the limbs. The axial skeleton, on the other hand, consists of the skull, vertebral column, rib cage, and sternum. It forms the central axis of the body and provides support and protection for the vital organs.

Red bone marrow is responsible for the production of red blood cells, white blood cells, and platelets. Red blood cells, or erythrocytes, are important for oxygen transport in the body. White blood cells, or leukocytes, are involved in immune responses and defense against infections. Platelets are responsible for blood clotting. Red bone marrow is found in the spongy or cancellous bone of certain bones, such as the sternum, ribs, vertebrae, and pelvis.

The skeletal system has several functions, including protection of internal organs, support for the body, storage of minerals (such as calcium and phosphorus), production of blood cells, and assistance in movement through muscle attachment. However, hormone production is not a direct function of the skeletal system. Hormones are produced by various endocrine glands located throughout the body.

Long bones, such as the femur and humerus, are characterized by their elongated shape and dense, compact structure. They consist of a shaft (diaphysis) and two ends (epiphyses) and are primarily involved in support, movement, and hematopoiesis (production of blood cells). Short bones, like the bones of the wrist and ankle, have a more cuboidal shape, while flat bones, such as the skull and ribs, are thin and flat. Irregular bones have complex shapes and do not fit into any of the other categories.

Cartilage is a flexible and resilient connective tissue that provides cushioning and support in the skeletal system. It acts as a shock absorber, reducing friction between bones and protecting them from damage during movement. Cartilage also allows for smooth joint articulation and flexibility in certain structures, such as the nose, ears, and the ends of long bones.

The maxilla is a facial bone and is not part of the cranium. The cranium, or skull, is composed of several bones that enclose and protect the brain. These include the occipital bone, frontal bone, temporal bones, parietal bones, sphenoid bone, and ethmoid bone. The maxilla is located in the upper jaw and forms the central part of the facial skeleton.

Synovial fluid is a viscous fluid that is found in the synovial joints. Its primary function is to lubricate the joint surfaces, reducing friction and allowing for smooth movement between the bones. It also helps nourish the articular cartilage and provides a shock-absorbing cushion during joint compression.

Calcium is the main mineral component of bone tissue. It provides strength and rigidity to the bones, making them hard and resistant to deformation. Calcium is stored in the bone matrix and is constantly being deposited and resorbed to maintain the balance of calcium levels in the body. Sodium, potassium, and iron are important minerals for various physiological functions but are not the primary components of bone tissue.