Function of the Skeleton System Provides the body with physical support Protection – vital organs Movement - bones = levers joints = fulcrum Storage of minerals (Calcium and Phosphorus) Blood formation (Hemopoiesis)
Classification of Bones Two main divisions Axial = skull, vertebral, and rib cage Appendicular = bones of upper and lower limbs, and the girdles that attach them to the axial
Bone types Long bones- Short bones- Short bones- Flat bones Flat bones One Fish One Fish Two Fish Two Fish Irregular bones- Irregular bones- Sesamoid (Seed like) Sesamoid (Seed like) Find these bones on our skeletons, Yossarian and Cassandra Find these bones on our skeletons, Yossarian and Cassandra
Bone Structure Bones are organs!!! They contain nervous tissue, connective tissue, epithelial tissues in their blood vessels and Osseous tissue or bone tissue which is the main tissue found in bones. – What major class of tissue is osseous tissue?
Bone Composition Spongy and Compact Bone Compact = external layer, the dense outer layer that appears smooth and solid. Spongy = internal part of the bone, a honeycomb of small needle-like or flat pieces called trabeculae – filled with red or yellow bone marrow
Yellow Marrow Found in a central tubular cavity in the long shaft of the bone. This cavity is called the Medullary Cavity. Fatty and delicious
Red Marrow Found in the trabecular cavities of spongy bone. Site of Hemopoiesis – In infants, the medullary cavity and all areas of spongy bone contain red marrow. – In adults, the medullary cavity extends into the ends of bones, and thus there is less red marrow tissue. Found in ends of large long bones, flat bones such as the sternum, and some irregular bones such as the hip.
Long Bone Structure Diaphysis = the long axis of the bone. Made of a relatively thick collar of compact bone, that surrounds the medullary cavity.
Epiphyses = the ends of the bone. Compact bone surrounds the exterior and spongy bone is in the interior. – The joint surface is covered with articular (hyaline) cartilage. Epiphyseal Line = line between the diaphysis and the epiphysis.
Membranes in Long Bone Periosteum = a white double membrane surrounding the entire bone except the joint surface.
Periosteum cont. Richly supplied with nerve fibers, lymphatic vessels, and blood vessels. These enter the diaphysis through a nutrient foramen.
Endosteum Membrane covering internal bone surfaces such as the trabeculae of spongy bone..