BIO 240 Dr. Gilley Lecture 13Outline of Last LectureI. Skeletal SystemA. FunctionsB. 4 main cell typesC. Bone TissueD. Bone MorphologyOutline of Current Lecture E. Long Bone AnatomyF. Growth PlatesG. Patterns of OssificationCurrent LectureI. Skeletal SystemA. FunctionsB. 4 main cell typesC. Bone TissueD. Bone Morphology1. Flat bones  Include all of the skull bones, sternum, scapula, and ribs.Is mostly spongy bone internally with a thin sheath of compact bone making up the outside2. Short bones  Include the wrist bones (carpals), ankle bones (tarsals), and the patella. Cube shaped; are about as wide as they are tall. There is a greater compilation of compact bone with less spongy bone on the inside, making them a little bit stronger. 3. Long bones  Include the femur, tibia, Humerus, radius, ulna, metacarpals, and metatarsals.4. Irregular bones Include the coxal bones and vertebrae.E. Long Bone Anatomy1. Articular cartilage  Hyaline cartilage on the ends of all long bones. 2. Epiphysis  The ends of the long bones. (Mostly spongy bone). Spongy bone with red marrow. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Red marrow Hemopoietic3. Diaphysis  The shaft of the long bone. (Mostly compact bone).a. Medullary cavity  Contains yellow marrow.b. Yellow marrow  For fat storage for energy. 4. Periosteum  Connective tissue wrapping on top of the bone. Made up of two layers. The superficial outer layer is the fibrous layer, which is dense regular connective tissue. The fibrous layer is continuous overjoints. The deep inner layer is the osteogenic layer, which contains osteoprogenitors, osteoblasts, and osteoclasts. (These three cells are the ones involved in bone production and shaping). The osteogenic layer is not continuous, it just covers one bone. 5. Endosteum  The lining of the medullary cavity. Is the functional equivalent to the osteogenic layer; contains osteoprogenitors, osteoblasts, and osteoclasts.F. Growth Plates1. Epiphyseal Plates  A band of hyaline cartilage at the junction of the diaphysis and epiphysis that allows for growth of long bones. Plate is present in juveniles, becomes epiphyseal line in adults after growth is complete. The long bones grow up until about 16- 18 years of age, when the epiphyseal plates ossify into epiphyseal lines. 2. Zone of resting cartilage  Area of the epiphyseal plate that becomesthe epiphyseal line.3. Zone of mitotic cartilage  Also called proliferation; cells below the resting cartilage that are making more cells and extending the epiphyseal plate downward. 4. Zone of hypertrophy  Cells below the zone of mitotic cartilage where the cells have stopped undergoing mitosis but the cells are enlarging. 5. Zone of calcified matrix  Cells below the zone of hypertrophy. Is invaded by osteoprogenitors, osteoblasts, and osteoclasts. Area where the cartilage is turned to bone. G. Patterns of Ossification1. Intramembranous Ossification  Starts with mesenchyme (prototype cartilage). Forms most of our flat bones. 2. Endochondrial Ossification  Starts with hyaline cartilage. Forms longand short bones. a. Primary ossification center  The middle of the long bone (diaphysis). This is what gets formed first; by endochondrial ossification.b. Secondary ossification center  The epiphysis of long bones. This is what is formed second, after the diaphysis, by endochondrial ossification.3. Combo of intramembranous and endochondrial  Starts with both mesenchyme and hyaline cartilage. Forms some flat bones and irregular