Question

What is the role of spongy bone as a tissue and the femur as a organ?

Answer 1

1. Cancellous bone makes up about 20 percent of the human skeleton, providing structural support and flexibility without the weight of compact bone. It is found in most areas of bone that are not subject to great mechanical stress. It makes up much of the enlarged ends (epiphyses) of the long bones and is the major component of the ribs, the shoulder blades, the flat bones of the skull, and a variety of short, flat bones elsewhere in the skeleton. Cancellous bone is usually surrounded by a shell of compact bone, which provides greater strength and rigidity. The open structure of cancellous bone enables it to dampen sudden stresses, as in load transmission through the joints. Varying proportions of space to bone are found in different bones according to the need for strength or flexibility. Cancellous bone also has a relatively high level of metabolic activity. It is highly vascularized and contains red bone marrow, thus facilitating RBCs and platelets production.

2. At the most basic level, the femur is classified as a bone in the skeletal system rather than an organ. However, it is sometimes classified as an organ as well because it is composed of several different tissue types and performs more functions than simply structural support.

Besides providing structural support, it has medullary cavity which contains red bone marrow, which is involved in the production of red blood cells. Over time, red bone marrow is replaced by yellow bone marrow, which helps to store fat.