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CHAPTER 36 THE SKELETAL, MUSCULAR & INTEGUMENTARY SYSTEMS
CHAPTER 36. 1 THE SKELETAL SYSTEM HW: P. 925 #1 -4
THE SKELETON • 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
Structure of Bones (Fig. 36. 3) • 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
BONE DEVELOPMENT • 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?
TYPES OF JOINTS • 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.
STRUCTURE OF JOINTS • Cartilage between bones helps reduce friction • Ligaments fuse with bone membranes and connect bone to bone. • Synovial fluid allows for smooth bone movement
SKELETAL SYSTEM DISORDERS • Arthritis: inflammation of joints • Osteoporosis: severe bone loss (mostly in women)
CHAPTER 36. 2 THE MUSCULAR SYSTEM HW: P. 931 #1 -5
TYPES OF MUSCLE TISSUE (Fig. 36 -6) • Skeletal muscle cells: long, slender, multi-nucleated and striated; voluntary (aka muscle fibers); attached to bones • Smooth muscle cells: spindle-shaped, one nuclei and nonstriated; involuntary; lines organs, vessels and digestive tract • Cardiac muscle cells: striated with one or two nuclei; involuntary; only found in the heart
SKELETAL MUSCLE STRUCTURE (Fig. 36 -7) • Thin (actin) & Thick (myosin) filaments myofibrils (sarcomere) muscle fiber (cell) bundle of muscle fibers skeletal muscle
MUSCLE CONTRACTION (Fig. 36 -8) • 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
MUSCLES AND BONES • 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.
CHAPTER 36. 3 The Integumentary System P. 936 #1 -5 P. 939 #1 -10, 14, 16, 23
THE SKIN • Functions: • Protection—barrier against infection and injury (most important) • Regulates body temp. • Removes waste • Protection against UV rays
THE STRUCTURE OF SKIN (Fig. 3613) • 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 AND NAILS • 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
SKIN DISEASES http: //science. howstuffworks. com/life/3 0564 -one-step-beyond-argyriavideo. htm