THE SKELETAL, MUSCULAR & INTEGUMENTARY SYSTEMS THE SKELETAL SYSTEM HW: P. 925 #1-4 Functions: Supports the body Protects internal organs Enables movement Stores mineral reserves Site for blood cell formation Axial: skull, vertebrae and rib cage Appendicular: bones of upper and lower limbs Bones: solid network of living cells and protein fibers surrounded by deposits of calcium salts Periosteum: tough layer of connective tissue that surrounds the bone Compact Bone: dense bone Haversian Canals: tube network for vessels and nerves Spongy Bone: lattice network of bone; adds support without mass Bone Marrow: soft tissue inside bone; yellow = fat; red = blood cell formation Ossification: cartilage replaced by bone Osteocytes: mature bone cells Osteoblasts: produce bone (blast off) Osteoclasts: break down bone Where can you find cartilage in your body? Joints: where bones attach; allow for movement without damage Types of joints: Immovable: no movement (i.e. skull bones) Slightly movable: small, restricted movements (i.e. vertebrae) Freely movable: movement in one or more directions Ball-and-socket: most movement (i.e. shoulder) Hinge: back-and-forth motion (i.e. knee, elbow) Pivot: bones rotate (i.e. forearm) Saddle: bones slide (i.e. thumb) Cartilage between bones helps reduce friction Ligaments fuse with bone membranes and connect bone to bone. Synovial fluid allows for smooth bone movement Arthritis: inflammation of joints Osteoporosis: severe bone loss (mostly in women) THE MUSCULAR SYSTEM HW: P. 931 #1-5 Skeletal muscle cells: long, slender, multi-nucleated and striated; voluntary (aka muscle fibers); attached to bones Smooth muscle cells: spindle-shaped, one nuclei and non-striated; involuntary; lines organs, vessels and digestive tract Cardiac muscle cells: striated with one or two nuclei; involuntary; only found in the heart Thin (actin) & Thick (myosin) filaments myofibrils (sarcomere) muscle fiber (cell) bundle of muscle fibers skeletal muscle Thick filaments: myosin protein Thin filaments: actin protein (thin and tin) Filaments arranged into a sarcomere (from Z to Z line) Sliding filament model: A muscle contracts when the thin filaments slide over the thick filaments. Energy for contraction supplied by ATP Neuromuscular junction: synapse between neuron and muscle cell Acetlycholine: neurotransmitter that binds to muscle fibers and causes calcium to release Calcium is KEY to muscle contractions (allows myosin to bind to actin) More muscle cells stimulated = stronger contraction Tendons connect muscles to bone. Muscles contract and tendons pull on bones, function like levers around a fixed point (joint) Regular exercise is important in maintaining muscular strength and flexibility. The Integumentary System P. 936 #1-5 P. 939 #1-10, 14, 16, 23 Functions: Protectionbarrier against infection and injury (most important) Regulates body temp. Removes waste Protection against UV rays Two layers: Epidermis: outer layer; dead and living cells (inner cells divide constantly) Keratin: tough, fibrous protein Melanocytes: cells that make melanin (brown skin pigment) Dermis: inner layer; contains vessels, nerves, glands, etc Hair: protection from UV rays; insulation from cold; traps dirt and other particles; grow from hair follicles (pockets in the dermis) Nails: made of keratin; grow from the nail root; protects tips of fingers and toes 64-one-step-beyond-argyria-video.htm