Lessons 8 9 An Introduction to the Skeletal System The Skeletal System Includes Bones of the skeleton Cartilages ligaments and connective tissues 2015 Pearson Education Inc 6 1 Functions of the Skeletal System Five Primary Functions of the Skeletal System 1 Support structural support for whole body attachment for soft tissues organs 2 Storage of Minerals calcium most abundant mineral in body and Lipids yellow bone marrow energy reserves 3 Blood Cell Production occurs in red bone marrow 4 Protection skull protects brain ribs protect heart lungs vertebrae protects spinal cord 5 Leverage force of motion allows body movement when skeletal muscles contract 2015 Pearson Education Inc 6 2 Classification of Bones Bones Are classified by Shape Bone markings surface features marks Internal tissue organization spongy compact 2015 Pearson Education Inc 6 2 Classification of Bones Six Bone Shapes 1 Sutural bones 2 Irregular bones 3 Short bones 4 Flat bones 5 Long bones 6 Sesamoid bones 2015 Pearson Education Inc Figure 6 1 A Classification of Bones by Shape Sutural bone Sutures a Sutural Bones Sutural bones or Wormian bones are small flat oddly shaped bones found between the flat bones of the skull They range in size from a grain of sand to a quarter Their borders are like pieces of a jigsaw puzzle b Irregular Bones Irregular bones have complex shapes with short flat notched or ridged surfaces The vertebrae that form the spinal column the bones of the pelvis and several bones in the skull are examples of irregular bones c Short Bones Short bones are boxlike in appearance Examples of short bones include the carpal bones wrists and tarsal bones ankles Vertebra Carpal bones d Flat Bones Flat bones have thin parallel surfaces Flat bones form the roof of the skull the sternum breastbone the ribs and scapulae shoulder blades They provide protection for underlying soft tissues and offer an extensive surface area for the attachment of skeletal muscles Parietal bone Sectional view e Long Bones Humerus f Sesamoid Bones Patella Long bones are relatively long and slender They are located in the arm and forearm thigh and leg palms soles fingers and toes The femur the long bone of the thigh is the largest and heaviest bone In the body Sesamoid bones are usually small round and flat They develop inside tendons and are most often encountered near joints at the knee the hands and the feet Few individuals have sesamoid bones at every possible location but everyone has sesamoid patellae pa TEL e singular patella a small shallow dish or kneecaps 6 2 Classification of Bones 1 Sutural Bones Small irregular bones Found between the flat bones of the skull Vary in size can be as small as a grain of sand to as wide as a quarter Irregular Bones Have complex shapes Examples spinal vertebrae pelvic bones some 2 bones in the skull 2015 Pearson Education Inc Figure 6 1a A Classification of Bones by Shape Sutural bone Sutures a Sutural Bones Sutural bones or Wormian bones are small flat oddly shaped bones found between the flat bones of the skull They range in size from a grain of sand to a quarter Their borders are like pieces of a jigsaw puzzle Figure 6 1b A Classification of Bones by Shape b Irregular Bones Irregular bones have complex shapes with short flat notched or ridged surfaces The vertebrae that form the spinal column the bones of the pelvis and several bones in the skull are examples of irregular bones Vertebra 6 2 Classification of Bones 3 Short Bones Small and thick Examples ankle and wrist bones 4 Flat Bones Thin with parallel surfaces Found in the roof of skull sternum ribs and scapulae 2015 Pearson Education Inc Figure 6 1c A Classification of Bones by Shape c Short Bones Short bones are boxlike in appearance Examples of short bones include the carpal bones wrists and tarsal bones ankles Carpal bones Figure 6 1d A Classification of Bones by Shape d Flat Bones Flat bones have thin parallel surfaces Flat bones form the roof of the skull the sternum breastbone the ribs and scapulae shoulder blades They provide protection for underlying soft tissues and offer an extensive surface area for the attachment of skeletal muscles Parietal bone Sectional view 6 2 Classification of Bones 5 Long Bones Long and thin Found in arms legs hands feet fingers and toes 6 Sesamoid Bones Small and flat shaped like a sesame seed Develop inside tendons near joints of knees hands and feet Ex The patella is a sesamoid bone Vary in location and abundance 2015 Pearson Education Inc Figure 6 1e A Classification of Bones by Shape e Long Bones Humerus Long bones are relatively long and slender They are located in the arm and forearm thigh and leg palms soles fingers and toes The femur the long bone of the thigh is the largest and heaviest bone In the body Figure 6 1f A Classification of Bones by Shape f Sesamoid Bones Patella Sesamoid bones are usually small round and flat They develop inside tendons and are most often encountered near joints at the knee the hands and the feet Few individuals have sesamoid bones at every possible location but everyone has sesamoid patellae pa TEL e singular patella a small shallow dish or kneecaps 6 2 Classification of Bones Bone Markings surface features of a bone Depressions grooves tunnels along bone surface Where blood and nerves lie alongside or penetrate into bone Elevations or projections Where tendons and ligaments attach Where articulations with other bones occur 2015 Pearson Education Inc 6 2 Classification of Bones Internal tissue organization Structure of a Long Bone Diaphysis The tubular shaft of the bone A heavy wall of compact bone or dense bone A central space called medullary marrow cavity Epiphysis Wide part at each end Articulation with other bones Mostly spongy cancellous bone Covered with compact bone cortex Metaphysis Where the diaphysis and epiphysis meet 2015 Pearson Education Inc Figure 6 3a Bone Structure Spongy bone Compact bone Epiphysis Metaphysis Diaphysis shaft Medullary cavity Metaphysis Epiphysis a The structure of a representative long bone the femur in longitudinal section 6 2 Classification of Bones Structure of a Flat Bone Resembles a sandwich of spongy bone between two layers of compact bone Ex The parietal bone of the skull Within the cranium the layer of spongy bone between the compact bone is called the diplo Red bone marrow is located in the spongy bone 2015 Pearson Education Inc Figure 6 3b Bone Structure Cortex Diplo compact bone b spongy bone The structure of
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