Lab Exam Notes #1, 2022 Update (PDF)

# Overview of the Skeleton: Classification and structure of Bones and Cartilage The Skeleton is made up of two tissues, the Bone and Cartilage. The embryo consists of mostly hyaline cartilage and the adult of mostly bone. Cartilage is found only in the bridge of the nose, larynx, the trachea, the j...

# Overview of the Skeleton: Classification and structure of Bones and Cartilage The Skeleton is made up of two tissues, the Bone and Cartilage. The embryo consists of mostly hyaline cartilage and the adult of mostly bone. Cartilage is found only in the bridge of the nose, larynx, the trachea, the joints and some in the ribcage and the ear. ## Functions of the Skeleton: 1. Support 2. Protection 3. Lever system for movement 4. Storage 5. Production of blood cells ## Subdivisions of the skeleton: - **The Axial Skeleton** is found at the center of gravity, the torso. It consists of the Skull, the Sternum, and the Vertebral Column. - **The Appendicular Skeleton** consists of the limbs and the Pelvic and Pectoral girdles. ## Bone Markings: Bone Markings are areas on the surfaces of the bones where ligaments, etc. attach, where joints are formed, and where nerves and blood vessels pass. There are two types of bone markings, projections, and depressions or cavities. ## Bone Markings list (know table 9.1) - **Tuberosity:** a large rounded projection. - **Crest:** a narrow ridge of bone; usually prominent. - **Trochanter:** a very large, blunt, irregularly shaped process (only seen in the femur). - **Line:** a narrow ridge of bone; less prominent than a crest. - **Tubercle:** a small rounded projection or process. - **Epicondyle:** a raised area on or above a condyle. - **Spine:** a sharp, slender, often pointed projection. - **Process:** any bony prominence. - **Head:** a bony expansion carried on a narrow neck. - **Facet:** smooth nearly flat articular surface. - **Condyle:** a rounded articular projection. - **Ramus:** an arm-like bar of bone. - **Groove:** a furrow. - **Fissure:** a narrow slit-like opening. - **Foramen:** a round or oval opening through a bone. - **Notch:** an indentation at the edge of a structure. - **Meatust:** a canal-like passageway. - **Sinus:** a bone cavity, filled with air and lined with mucous membrane. - **Fossa:** shallow basin-like depression in a bone, often serving as an articular surface. # Classification of bones There are 206 bones in the human body. ## Types of bones 1. **Compact bone:** which is smooth looking and homogeneous. 2. **Spongy bones:** which consists of small trabeculae, bars of bones, and space. ## Subtypes of bones 1. **Long bones:** such as the femur, which are longer than wide, have a shaft and heads at the end. These bones are mostly compact bone. 2. **Short bones:** such as the tarsals, which are cube shaped, contain more spongy bone than compact bone. 3. **Flat bones:** such as the bones of the skull, consist of two layers of thin compact bone with spongy bone in between. Many of these bones are curved. 4. **Irregular bones:** such as the vertebrae, which are unusually shaped. ## Other subtypes of bones: 1. **Sesamoid bones:** which are found inside of tendons, ex. the patella. 2. **Wormian/Sutural bones:** which are small bones found between the cranial bones. # Anatomy of a long bone ## The Shaft or Diaphysis This is found on the long axis, consisting mostly of compact bone. ## The Periosteum This is a fibrous membrane covering that surrounds the outside of the bone. Sharpey’s fibers from the periosteum plunge into the bone allowing blood vessels and nerves to enter the bone. **Osteoblasts** are bone forming cells and are found in the periosteum. **Osteoclasts** are bone destroying cells and are found in the endosteum, the inner surface lining of the shaft. ## The Epiphysis This is found at the end of long bones, and consists of mostly spongy bone and a thin layer of compact bone. ## The Articular cartilage This is made of hyaline cartilage and covers the epiphyseal surface of the long bone instead of periosteum. It is a smooth surface that prevents friction at the joints.. ## The Epiphyseal plate This is an area of hyaline cartilage that allows for growth in growing animals. ## The Epiphyseal line This is a remnant of plate of bone growth. ## The Central Cavity of the shaft This is also called the Medullary cavity and stores fat. In infants the cavity stores red marrow, in adults the red