The haversian canal allows capillaries and nerves to pass through the cortical bone to nourish osteocytes, osteoclasts, and osteoblasts. Both the white and the red bone marrow are contained within trabecular bone, while the periosteum is a thin, highly innervated membrane on the outside of bone.

Calcium is essential for many processes of the body, including but not limited to nerve conduction, muscle contraction, blood clotting, and bone mineralization.

In adults, hematopoietic bone marrow is generally confined to the flat bones, including the sternum, the skull, the ribs, and the pelvis. Hematopoietic bone marrow also exists in the proximal end of the femur in most adults, but is not generally found in the tibia or fibula.

Long bones are lengthened during childhood and adolescence via a process referred to as endochondral ossification. In this process, chondrocytes of the growth plate hypertrophy and eventual die, leaving cavities that are then colonized by osteoprogenitor cells. These osteoprogenitor cells then differentiate into osteoblasts, which mineralize the newly forming bone. None of the other answers are actual processes in bone formation or physiology.

The functional unit of compact bone is the osteon. The osteon is formed by concentric layers of compact bone called lamellae. These surround a central canal called the haversian canal. Trabeculae are the functional units of cancellous (spongy) bone.

Bones are made up of the following three primary tissue types:

I: Cortical bone, which is the hard exterior layer (also referred to as "compact bone);

II: Cancellous bone, which is the porous bone tissue that fills the center of bones (also referred to as "spongy bone" or "trabecular" bone tissue); and

III: Bone marrow, a hematopoietic tissue that fills spaces in trabecular bone.

Muscle attaches to bone via tendons, fibrous extensions of the sheath of the muscle body that are primarily composed of tightly packed collagen fibers. In comparison, ligaments attach bones to other bones without involvement with a muscle, such as the ligaments between the metacarpals of the wrist. Sutures are fibrous joints of the cranium, and hyaline cartilage is at the point of articulation of many bones but it is neither incorporated into muscle structure, nor does it attach to the bone with which it articulates. Rather, articular cartilage primarily serves to allow bones to glide more easily over each other during movement.

Variation in color of bone marrow cells is not related to their level of activity, calcification, or the types of blood cells they produce. Rather, "red marrow" is primarily hematopoietic cells (both red and white progenitor cells) while "yellow marrow" is primarily composed of fat cells.

The behavior of cells in the zones of endochondral ossification is as follows:

• The resting zone: normal resting chondrocytes within hyaline cartilage
• The zone of proliferation: rapid mitosis of chondrocytes
• The zone of maturation: hypertrophy of chondrocytes
• The zone of calcification: the death of chondrocytes due to lack of nutrients and inability to eliminate cellular wastes
• The zone of ossification: migration of osteoprogenitor cells into the cavities left behind by dead chondrocytes and mineralization of newly formed bone

There are five distinct zones in regions of endochondral ossification. These are the resting zone, the zone of proliferation, the zone of maturation, the zone of calcification, and the zone of ossification.