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The Human Body Plan Skeletal & Muscular Systems The Body Tissues I. The Body Tissues: tissues are a group of similar cells: (we’ll talk about a few) muscle (msl) tissue are cells that contract. 3 types of msl tissue: skeletal, cardiac (heart), & smooth Nervous tissue: cells that receive & transmit messages in the form of electrical impulses called neurons; makes up the brain & spinal cord. Connective tissue: cells that bind, support, & protect structures; eg: bones, tendons, ligaments, organ wall fibers, blood, & others. II. Skeletal System (see h.o. of skeleton) The Skeleton = endoskeleton, has 2 major divisions: 1. Axial: skull, ribs, & spinal cord 2. Appendicular: the limbs A. Functions: provides support & form, Surface for msl attachment, Protect vital organs, Store minerals, Red marrow produces blood cells. B. Bone Structure: • the periosteum covers bone, attaches muscles, where vessels enters the bone • Hard compact bone:on the outside; gives bone strength • Spongy Bone: outer ends of the bone, porous, gives bone strength • marrow (bld forming tissue) on the inside: red & yellow marrow • Haversian canals : channels in the bone that supply blood vessels Osteocytes: bone cells arranged around Haversian canals Injury & repair: fracture: crack or break; if circulation is maintained & periosteum survives healing occurs C. Bone Development: Ossification: becoming bone. Bones may be formed from: – Cartilage: some remains permanent – Membrane layers: form flat bones – Sutures: newborn skulls – irregular seams • Bone elongation: occurs @ the ends of long bones @ end plates composed of cartilage cells • growth continues until all cartilage in the epiphyseal plate is replaced. II. Joints: place where 2 bones meet. A. Types synovial Joints: synovial joints are those in which the articulating bones are separated by a fluid containing joint cavity 1. Fixed: no movement; eg: skull 2. Partially Movable (semi movable): limited movement; eg: vertebrae ribs sternum 3. Movable Joints a) Ball & Socket: rotates; eg: hip & shoulder c) Angular: wrist & ankle d) Gliding: eg: hand & foot bones, vertebrae e) Pivot: eg: head neck; rotation of forearm g. saddle: a saddle joint allows movement back and forth and up and down, but does not allow for rotation like a ball and socket joint. B. Ligaments: connect bone-bone, can stretch. Lined w/cartilage lubricated by secretions. The knee & shoulder have cushions called bursae (bursitis) Arthritis: painful, swollen joints. 1. Rheumatoid Arthritis: immune system begins to attack body tissues; joints become inflamed, swollen, stiff, & deformed. 2. Osteoarthritis: degenerative joint disease; bone rub against bone • III. The Muscular System A. 3 Types 1. Skeletal: aka as striated & voluntary msl; has/many nuclei. The body contain about 656 msls. 2. Smooth: no striation: smooth & involuntary. Visceral; in the walls of blood vessels, G-I tract. One nuclei/cell. 3. Cardiac: heart msl; striated BUT involuntary Muscles are responsible for all movement of the body B. Muscular Structure 1.Requires constant supply of O2 & nutrients 2.Motor unit: initiates msl contraction. Involves muscle fibers & nerve cells 3.Msl fibers: consists of myofibrils – thread-like thick & thin protein filaments; thin=actin, thick= myosin Msl Contraction: when a muscle contracts its working; the actin & myosin filament slide pass each other shortening. Requires ATP. If a msl is NOT working, it’s not contracting, it’s longer. • • • • C. Characteristics of Muscle: Skeletal and smooth muscle are elongated. Muscle cell = muscle fiber Contraction of a muscle is due to movement of microfilaments (protein fibers) All muscles share some terminology a. Prefixes myo and mys refer to muscle b. Prefix sarco refers to flesh D. Shapes of Muscles: Triangular- shoulder, neck Spindle- arms, legs Flat- diaphragm, forehead Circular- mouth, anus E. Skeletal Muscle: most are attached by tendons to bones. Cells have more than one nucleus (multinucleated) Striated- have stripes, banding, Voluntary- subject to conscious control Tendons are mostly made of collagen fibers Found in the limbs Produce movement, maintain posture, generate heat, stabilize joints F. Cellular Structure of Skeletal Muscle: Each cell (fibre) is long and cylindrical. Muscle fibres are multi-nucleated, typically 50-60mm in diameter, and up to 10cm long. The contractile elements of skeletal muscle cells are myofibrils. G. Skeletal muscle – Summary Voluntary movement of skeletal parts Spans joints and attached to skeleton Multi-nucleated, striated, cylindrical fibres H. Muscle Control Type of muscle Nervous control Type of control Example Skeletal Skeletal Controlled by CNS Voluntary Lifting a glass Regulated by ANS Involuntary Heart beating Controlled by ANS Involuntary Peristalsis Cardiac Smooth 1. Types of Responses: 2. Twitcha. A single brief contraction b. Not a normal muscle function 3. Tetanus a. One contraction immediately followed by another b. Muscle never completely returns to a relaxed state c. Effects are compounded I. Where Does the Energy Come From? Energy is stored in the muscles in the form of ATP. ATP comes from the breakdown of glucose during Cellular Respiration. This all happens in the Mitochondria of the cell.When a muscle is fatigued (tired) it is unable to contract because of lack of Oxygen J. Exercise and Muscles • Isotonic- muscles shorten and movement occurs ( most normal exercise) • Isometric- tension in muscles increases, no movement occurs (pushing one hand against the other) K. Msl & Bone Movement: 1. Tendon: connect msl to bone. a. Origin: point where msl attaches to a stationary bone. Eg: biceps msl to shoulder b. Insertion: point where msl attaches to moving bone. Eg. biceps tendon to radius. L. Muscle Actions: • Flexors: msls that bend a joint (biceps) • Extensors: msls that extend a joint (triceps) Terms: Hyperextension: When a joint is extended past the anatomical position the movement is called hyperextension. Abduction: move toward the body’s center Abduction: move away from the body’s center Circumduction: the circular motion of a limb Rotation: motion moves a structure in a rotational motion along a longitudinal axis such as turning your neck to look at either side. Inversion- turn sole of foot medially Eversion- turn sole of foot laterally Pronation- palm facing down Supination- palm facing up Opposition- thumb touches tips of fingers on the same hand M. Msl Fatigue: msl converts glycogen to glucose for ATP prodxn (nrg); msl fatigue is the inability of msls to contract due to lack of ATP N. Exercise: strengthens muscles & helps prevent injuries; not just skeletal msl but heart msl, joints, & ligament **** I. A. B. C. D. E. F. G. H. I. J. K. The Skeletal Muscles: There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this section we will only study a sample of the major muscles. Trapezius: Extend Head, Adduct, Elevate or Depress Scapula Latissimus dorsi: Extend, Adduct & Rotate Arm Medially Deltoids: Delts. The deltoid covers the shoulder and has the shape of a delta. Pectoralis major: “pecs”; flexes, adducts & rotates medially Biceps brachii: “bis, guns” flexor: flexes elbow Triceps: “tris”; extensor: extends the elbow Rectus abdominus: “abs, 6 pack” flexes abdomen External oblique: compresses abdomen Forearm msls: Flexor Capri: flexes wrist Extensor Capri: extends wrist Flexor digitorum: flexes fingers Extensor digitorum: extends fingers Pronator: pronates palm Supinator: supinates palm Gluteus maximus: “glutes” Quadraceps: “quads” great extensor of the knee/foreleg Vastus lateralis Vastus intermedius L. M. Vastus medius Rectus femoris (tear drop) Biceps femoris: flexor: extends thigh & flexes lower leg Gastrocnemius: plantar: flexes foot & lower leg