Are humans tetrapods?
Two types of body components: • Visceral body components are derived from or associated with the gut or coelom. These include the digestive tract and other organs of the body cavity, as well as muscles, nerves, and skeletal parts. • Somatic body components are elements of the outer body; the integument, body wall, and their derivatives. The Cuticle is the outermost layer of the epidermis, composed of sloughed dead cells and cell secretions that cover the living cells of the epidermis. Bone development: Ossification is the gradual transition from a soft template to bone. • Endochondral bone – is dense and has a system of Haversian canals through which blood vessels can pass. These three stages are the way most bones in the body are formed: • Fibrous connective tissue develops first. • Cartilage forms from the fibrous tissue. • Finally, a bone matryx replaces the cartilage. • Intermembranous bone – develops between two layers of fibrous connective tissue without the cartilage stage. The
