The Skeletal Systems The 206 Bones In Your Body

Functions of Skeletal System Supports bodySupports body Protects internal organsProtects internal organs –i.e. skull protects brain Provides for movementProvides for movement –Bones=Levers Stores Mineral reservesStores Mineral reserves –Important to body reserves Provide site for blood cell formationProvide site for blood cell formation –Produced in soft marrow tissue that fills internal cavities

Different Parts of Skeletal System Axial SkeletonAxial Skeleton –Supports central axis of body –i.e. skull, vertebrae column, rib cage Skull Vertebrae Column Rib Cage

Different Parts (cont.) Appendicular SkeletonAppendicular Skeleton –Arms –Legs –Pelvis –Shoulder Lower Extremities (Thigh, Leg, Foot, Patella) Upper Extremities (Arm, Forearm, Hand) Shoulder Girdle (Clavicle, Scapula) Pelvic Girdle (Coxal—Hip bones)

Structure of Bones Solid network of living cells and protein fibers that are surrounded by deposits of calcium saltsSolid network of living cells and protein fibers that are surrounded by deposits of calcium salts Surrounded by periosteumSurrounded by periosteum –Blood vessels that pass through carry oxygen and nutrients Beneath is Haversain canalBeneath is Haversain canal –Contains blood vessels and nerves –Runs through compact bone Less dense tissue is spongy boneLess dense tissue is spongy bone –Outside of compact bone

Bone Cells OsteocytesOsteocytes –Mature bone cells –Embedded in bone matrix OsteoclastsOsteoclasts –Break down bone OsteoblastsOsteoblasts –Produce Bone

Bone Marrow Within bones are a soft tissue called bone marrow.Within bones are a soft tissue called bone marrow. –Yellow marrow: made up of fat cells –Red marrow: Produce red blood cells, some kinds of white blood cells, and cell fragments called platelets

Development of Bones CartilageCartilage –Skeleton of an embryo and composed almost entirely of a connective tissue –Must rely on diffusion of nutrients from tiny blood vessels in surrounding tissues Cartilage is replaced by bone during the process of bone formation called ossificationCartilage is replaced by bone during the process of bone formation called ossification

Joints A place where one bone attaches to another boneA place where one bone attaches to another bone Immovable JointsImmovable Joints –No movement –Interlocked and held by connective tissue or fused Slightly Movable JointsSlightly Movable Joints –Permit a small amount of restricted movement –Separated from each other Fixed Joint Slightly Movable (Joints between adjacent vertebrae)

Movable Joints Freely Movable JointsFreely Movable Joints –Permit movement in one or more directions Most common typeMost common type –Ball-and-Socket Joint permit movement in many directions –Hinge joints permit back- and-forth motion –Pivot joints rotate around another –Saddle joints one bone to slide in two directions

Structure of Joints  Surrounded by a fibrous joint capsule—helps hold the bones together while still allowing to move One layer forms strips of tough connective tissue called ligamentsOne layer forms strips of tough connective tissue called ligaments –Attached to the membranes that surround bones Cells in other layer of joint capsule produce substance called synovial fluidCells in other layer of joint capsule produce substance called synovial fluid –Forms a thin film on cartilage that covers bony surfaces that form the joint

Osteoporosis Bones lose densityBones lose density –Density = Strength Bones become fragileBones become fragile –Can cause breaks in hips, wrist, and spine.

How Osteoporosis Occurs Bones become fragile due toBones become fragile due to –Aging –Low intake of calcium –Family History –Cigarette smoking –Low estrogen levels –Vitamin D deficiency.

Osteoporosis Consequences Can cause bones to break.Can cause bones to break. –Leads to major disability –Many breaks in the spine can occur more than once. Decreased quality of life and disability.Decreased quality of life and disability.

Osteoporosis Symptoms Osteoporosis is especially hard to diagnose because there are few symptoms.Osteoporosis is especially hard to diagnose because there are few symptoms. The only way to tell is if there is chronic back pain, which could suggest a fracture of the spine.The only way to tell is if there is chronic back pain, which could suggest a fracture of the spine. If a fracture occurs during normal activity, you may want to check if you have osteporosis.If a fracture occurs during normal activity, you may want to check if you have osteporosis.

Prevention of Osteoporosis Drink more milk with vitamin D.Drink more milk with vitamin D. Certain medications can help fortify bones.Certain medications can help fortify bones. Exercise, although not strenuous.Exercise, although not strenuous. Not smoking.Not smoking. Also, there are vitamins that can help provide calcium and vitamin D.Also, there are vitamins that can help provide calcium and vitamin D.