He talks about the anatomy of the skeletal system, including the flat, short, and irregular bones, and their individual arrangements of compact and spongy bone.
The bones of the appendicular skeleton provide support and flexibility at the joints and anchor the muscles that move the limbs movement the bones of the skeletal system act as attachment points for the skeletal muscles of the body almost every skeletal muscle works by pulling two or more bones either closer together or further apart. A bone is a rigid organ that constitutes part of the vertebrate skeleton bones support and protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility bones come in a variety of shapes and sizes and have a complex internal and external structure.
A long bone has two parts: the diaphysis and the epiphysis the diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone the hollow region in the diaphysis is called the medullary cavity, which is filled with yellow marrow the walls of the diaphysis are composed of dense and hard compact bone. Anatomy of a flat bone this cross-section of a flat bone shows the spongy bone (diploë) lined on either side by a layer of compact bone bone markings the surface features of bones vary considerably, depending on the function and location in the body.
All bones contain bone marrow, which is either red or yellow red bone marrow is where red blood cells are formed yellow bone marrow is made up of fat or adipose cells each bone can have bone markings, or ways to describe the different projections and grooves in the bone.