Skeletal System

Functions Support- framework of the body Movement- many of the muscles attach to the skeleton Protection- protects vital organs injury Mineral Reservoir- calcium, phosphorus, sodium, potassium, and other minerals stored in the bones. Hemopoiesis- following birth, red marrow produce blood cells found in circulatory system.

Skeletal Organization Axial Skeleton Skull Hyoid bone Vertebral column Thoracic cage Appendicular Skeleton Pectoral girdle Upper limbs Pelvic girdle Lower limbs

Structure of Bones Diaphysis- bone shaft (femur, tibia, ulna) Compact bone- tightly packed together tissue, is solid, strong, and resistant to bending. Medullary cavity- yellow marrow, fat storage area. Inactive in blood cell production. Endosteum- thin layer of connective tissue that lines medullary cavity.

Epiphysis- two ends of the shaft. Compact bone- outer surfaces Spongy bone- red marrow that functions in prod. red blood cells, certain white blood cells, and platelets. Red because of oxygen carrying pigment called hemoglobin.

Microscopic Parts of a Bone Haversian Canal- contains at least one blood capillary which is source for nutrients and means of waste disposal. Lacunae- small cavities or spaces that contain a cell. Osteocyte- bone cell Canaliculi- canals that link one lacuna to another.

Fractures Compound- broken bone sticks out of skin Simple- break that does not come through the skin

Types of Breaks Transverse- break occurs at a right angle Oblique- break occurs at an angle other then right. Spiral- spiral or s-shaped; caused by a twisting action Longitudinal- fracture splits bone lengthwise Greenstick- incomplete fracture in the long axis of the bone. Compression- bones are pressed together.

Depressed- fracture due to denting in a bone. Impacted- broken ends are jammed together. Comminuted- produced by severe, direct violence; three or more fragments.

Body Movements Flexion- bending parts at a joint so angle is closer together. ( bending knee) Extension- straightening parts at a joint so angle increases. (straightening knee) Dorsiflexion- bending the foot at the ankle toward the shin. Plantar flexion- bending the foot at the ankle toward the sole. (downward)

Hyperextension- excess extension of the parts at a joint, past the normal position. Abduction- moving a part away from the midline (lift arm to form right angle) Adduction- moving a part toward the midline (returning arm to the side of the body) Rotation- moving a part around an axis (head)

Circumduction- moving a part so that its end follows a circular path Circumduction- moving a part so that its end follows a circular path. (moving finger in circle w/o moving hand) Pronation- turning body part so that it is facing downward (posterior) Supination- turning a body part so that it is facing upward (anterior) Eversion- turning the foot so that the sole faces laterally. (out)

Inversion- turning the foot so that the sole faces medially (in) Retraction- moving a part backward Protraction- moving a part forward elevation- raising a part (shrugging shoulders) Depression- lowering a part (drooping shoulders)