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Types of Muscle Cells Skeletal (Voluntary, Striated) Muscle Smooth (Involuntary, Smooth) Muscle these are muscles you control; the ones you exercise. these are muscles you cannot control They work the inner parts of the body (viscera) Cardiac Muscle (Involuntary, striated) myogenic due to interconnections These muscles of the heart do not get tired. Types of Muscle Cells Smooth Muscle Cells Cardiac Muscle Cells Skeletal Muscle Cells Tissues in Skeletal Muscles 1. 2. 3. Skeletal muscle tissue Connective Tissue Components Nervous Tissue Connective Tissue Components Endomysium Perimysium Fascicles Epimysium Tendon Tendon Pictures Aponeurosis Also may be formed from the three fibrous wrappings may merge with the wrappings of another muscle. Size and Shape of Fibers Size: varies from large to small Shape: varies Broad: Latisimus dorsi Narrow: Sartorius Flat: Latisimus dorsi Bulky: Gastrocnemius Long: Sartorius Circular: Orbicularis oris Triangular: Deltoid Shape: Broad Latisimus dorsi Shape: Narrow Sartorius Shape: Flat Latisimus dorsi Shape: Bulky Gastrocnemius Shape: Long Sartorius Shape: Circular Orbicularis oris Shape: Triangular Deltoid Fiber Arrangement Arrangement of SMF within the muscle, varies. Parallel to long axis Converge to narrow attachment Oblique are slanted Pennate – “think feather pen” Bipennate Curved Parallel to long axis Horizontal: Transversus abdominis Vertical Rectus abdominis Converge to narrow attachment Pectoralis major Oblique are slanted External oblique Pennate – “think feather pen” Vastus group Bipennate “two feathered” Rectus femoris Curved Fibers are circular Orbicularus oris Attachment of Muscles-Joints Most muscles attach articulating bones across a joint. Upon contraction of the muscle, one bone remains in a fixed position and the other moves. Pelvis Femur Attachment of Muscles- Origin Origin The point of attachment that does not move during muscle contraction. Pelvis Attachment of Muscles- Insertion – the point of attachment that does move when the muscles contract. Insertion Femur Attachment of Muscles-Contraction Typically, when a muscle contracts, the insertion is moved closer to the origin. ROLE OF MUSCLES, BONES, AND JOINTS IN MOVEMENT Lever any rigid bar free to move around a fixed point called a fulcrum Lever system Rigid bar - a bone F = Fulcrum - joint L = Load: Weight – resistance P a point around which the rigid bar rotates something that is moved = Pull - Muscle contraction force producing the movement Muscle Groups Muscles work together! Some muscles in a group contract while other relax. Prime mover Antagonist Synergists Fixator muscles Prime Mover A muscle or group of muscles which directly performs a specific movement. Flexion of forearmBiceps brachii is PM Antagonist When actively contracting, they oppose the movement of the prime mover. They are relaxed when the prime mover is contracting. Flexion of forearmT. brachii is anatagonist Synergists contract at the same time as the prime movers; they complement the prime movers. Flexion of forearmbrachialis is synergist Fixator muscles usually serve to stabilize joints. They help to maintain balance and posture during the contractions of the prime movers. Naming of Muscles Location Function - named for what they do Shape - shape of the muscle Direction of fibers - orientation of fibers Number of divisions or heads - connections Points of attachment - what bones are attached to OR bone markings Size - how big is the muscle relative to other muscles Location brachialis - in the arm Function - named for what they do Adductor group move leg toward the midline Shape - shape of the muscle deltoid - triangular muscle in the shoulder Direction of fibers - orientation of fibers rectus abdominus Oblique rectus refers to up and down slanting transversus Number of divisions or heads – connections biceps brachii Points of attachment What bones are attached to OR bone markings Sternocleidomastoid Size how big is the muscle relative to other muscles Gluteus maximus – in human beings, bigger than gluteus medius and minimus.
