| A | B |
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| What is the purpose of the skeletal system? | Supports the body, protects internal organs,Provides for movement,Stores mineral reserves,Provides a site for blood cell formation |
| Structure of Bones | Bones are a solid network of living cells and protein fibers that are surrounded by deposits of calcium salts |
| Axial skeleton – | supports the central axis of the body and consists of the skull, the vertebral column, and the rib cage |
| Appendicular skeleton – | the bones of the arms and legs as well as the pelvis and shoulders. |
| Bones are | a solid network of living cells and protein fibers that are surrounded by deposits of calcium salts. |
| Periosteum – | tough layer of connective tissue that surrounds and protects the bone. |
| Haversian cannals – | a network of tubes that run through the bone they contain blood vessels and nerves |
| Compact bone – | thick, very dense layer of bone. |
| Spongy bone – | looks like a sponge, found in the ends of long bones and in the middle part of short flat bones. The latticework of spongy bone helps add strength to bone with out adding mass |
| Bone marrow – | , site of blood cell production, made up primarily of fat cells and red marrow produces red blood cells, some white blood cells and platelets,soft tissue |
| Cartilage – | a type of flexible, cushy connective tissue. Found between bones.Cells are scattered in network of protein fibers (collagen and elastin), Does not contain blood vessels, Dense and fibrous despite extreme flexibility |
| Ossification – | Process of bone formation, cartilage is replaced by bone. |
| Osteoblasts – | cells that create bone. |
| Osteocytes – | maintain the cellular activities of bone. |
| Osteoclasts – | break down bone. |
| A joint is | a place where one bone attaches to another bone. |
| Immovable joint– | allows no movement. Ex. The skull, coccyx |
| Slightly movable joint– | permit a small amount of restricted movement. Ex. The two bones of the lower leg and the vertebrae |
| Freely movable joint– | permit movement in one or more directions. Ex. Shoulder, knee. |
| Ball-and-Socket – | moves just as its name suggests. Ex. The shoulder, the hip |
| Hinge joint – | moves like the hinge on a door. Ex. Knee and elbow |
| Pivot joint – | allows for rotation. Ex. Head/neck and the elbow/radius |
| Saddle joint – | bones glide/slide past one another. Ex. Wrist and ankle bones. |
| Sinovial Fluid – | forms a thin film within the bone surfaces of a joint |
| Bursae – | small sacs of sinovial fluid |
| arthritis- | Inflammation of joints |
| Ligaments – | hold bones together |
| Synovial Fluid – | forms a thin film within the bone surfaces of a joint |
| Skeletal Muscle | Striated – bandlike/stripelike appearance, Voluntary Muscle, Move Bones, Found in: Arms, legs,Any muscle you have control over |
| Smooth Muscle | Not striated – no bandlike/stripelike appearance, Involuntary muscle,Not connected to bones, Found in:Digestive organs (stomach, intestines), Blood vessels |
| Cardiac Muscle | Straited – bandlike/stripelike appearance, Involuntary, Found in:Heart only |
| Muscle Contraction | Striations in skeletal muscle cells are formed by an alternating pattern of thick and thin filaments, A muscle contracts when the thin filaments (actin) in the muscle fiber slide over the thick filaments |
| Myosin – | thick filament |
| Actin – | thin filaments |
| Control of Muscle Contraction | Motor neurons connect the CNS to skeletal muscle cells., Impulses from motor neurons control the contraction of skeletal muscle fibers. |
| Neuromuscular Junction – | point of contact between a motor neuron and a skeletal muscle cell |
