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Published byRegina Jennings Modified over 9 years ago
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Movement Posture Stabilize joints Generate heat
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Compare all three muscle types. Look at: Location/number of nuclei Associated structures What controls the muscle contraction? You should be able to answer the “Practice” questions on page 301when finished.
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Muscle (wrapped in fascia, epimysium) Fascicles (bundles of muscle fibers, wrapped in perimysium) Muscle Fibers (cells, wrapped in endomysium) Myofibrils Filaments
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Skeletal muscle fiber = single muscle cell Multinucleated Striated Myofibrils: myosin (thick filaments) and actin (thin filaments) Myosin and actin alternate forming striations (light and dark areas)
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Sarcomeres – pattern of actin/myosin alternating throughout muscle fiber Contractile unit of muscle Sarcolemma – cell membrane of muscle cells Sarcoplasm – cytoplasm of muscle cells
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http://www.youtube.com/watch?v=EdHz KYDxrKc http://www.youtube.com/watch?v=EdHz KYDxrKc
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Muscle Epimysium Endomysium Perimysium Fascicle Muscle fiber/cell Myofibrils Sarcolemma Sarcoplasm
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Actin Myosin Z line I band A band H zone Sarcomere Sarcoplasmic Reticulum
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Myosin: composed of many myosin fibers Heads and tails Forms cross-bridge with actin Heads of myosin come in contact with actin during muscle contraction Actin: double strands twisted into a helix Troponin – wraps around actin Tropomyosin – contact point for myosin
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Troponin Tropomyosin Thin filament
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Heads Tails Thick filament
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Corresponds with the endoplasmic reticulum in other cells Cisternae Enlarged portions of SR on either side of the T tubule Transverse tubules (T tubules) Extends into sarcoplasm, contains extracellular fluid
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T tubule Sarcoplasmic reticulum Sarcomere Myosin Actin Sarcolemma Mitochondria Myofibril
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Occurs when thin and thick filaments slide past one another Shortens sarcomeres/whole muscle cell Stimulated by neurons
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Motor neurons control skeletal muscle Neuromuscular junction: where nerve cell synapses with the muscle Motor end plate: specialized part of muscle to receive neural signals (higher amount of mitochondria, nuclei/SR)
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One motor neuron can innervate many muscle cells Motor unit: neuron AND the muscle(s) it controls
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Separation between the neuron and the muscle Nerve fiber releases synaptic vesicles containing neurotransmitters into the synaptic cleft
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Acetylcholine (ACh) Increases membrane permeability to sodium Sodium influx causes muscle impulse which transmits the contraction along the muscle Through the sarcoplasmic reticulum, cisternae, T tubules
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Sarcomeres shorten through movement of actin and myosin sliding past one another, not shortening themselves H zone, A bands narrow Z lines come closer together Needs ATP (energy), Ca 2+
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http://www.youtube.com/watch?v=Vlchs 4omFDM http://www.youtube.com/watch?v=Vlchs 4omFDM
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Summarize the contraction cycle in your textbooks (pg. 292) Summarize relaxation What enzyme is needed? What does this enzyme do? When ACh breaks down, what happens?
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Cellular respiration is critical in muscle contraction Myoglobin stores oxygen in muscle cells Gives muscle the reddish/brown color Similar to what other molecule?
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Lactic acid threshold Muscle forms lactic acid in absence of oxygen Anaerobic respiration
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Loss of ability to contract Caused by: decrease in blood flow, ion imbalances, accumulation of lactic acid in muscle tissue Cramps: sustained contraction of muscle Changes in extracellular matrix of muscle causes extended contraction
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Muscle is a major source of body heat Blood transfers heat throughout body
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Use your textbook to compare and contrast fast twitch and slow twitch muscles Give some examples for the ideal muscle types for different activities Use human and animals in your answer.
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http://www.youtube.com/watch?v=bUnzl kZGkvM http://www.youtube.com/watch?v=bUnzl kZGkvM
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http://www.gwc.maricopa.edu/class/bio 201/head/head1b.htm http://www.gwc.maricopa.edu/class/bio 201/head/head1b.htm Muscles of facial expression Muscles of mastication
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Epicranius Frontalis Temporalis Orbicularis occuli Orbicularis oris Buccinator
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Masseter – elevates mandible Temporalis – elevates mandible
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Sternocleidomastoid – pulls head to one side, flexes neck, elevates sternum
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Trapezius – rotates scapula, pull scapula (raise, medial, downward) Rhomboid major – connects scapula with vertebrae Rhomboid minor – smaller than rhomboid major, connects scapula with vertebrae Levator scapulae – elevates scapula
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Levator scapulae Trapezius Rhomboid major and minor (external oblique) (Latissimus dorsi) (Deltoid)
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We need to get into the muscle actions: Flexor – flexion – bend at joint so angle between two parts gets closer together Extensor – extension – straightening joint so angle between two parts increases Abductors – abduction – movement away from the midline Adductors – adduction – movement toward the midline Rotators – movement around an axis
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Posterior: http://www.gwc.maricopa.edu/class/bio 201/muscle/musc14.htm http://www.gwc.maricopa.edu/class/bio 201/muscle/musc14.htm Anterior: http://www.gwc.maricopa.edu/class/bio 201/muscle/musc13.htm http://www.gwc.maricopa.edu/class/bio 201/muscle/musc13.htm
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Posterior Shoulder: http://www.gwc.maricopa.edu/class/bio 201/muscle/arm/shldrp.htm http://www.gwc.maricopa.edu/class/bio 201/muscle/arm/shldrp.htm Anterior Shoulder: http://www.gwc.maricopa.edu/class/bio 201/muscle/arm/shldra.htm http://www.gwc.maricopa.edu/class/bio 201/muscle/arm/shldra.htm
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Coracobrachialis Scapula to middle of humerus Flexes and adducts arm Pectoralis major Thick muscle of upper chest Flexes, adducts, rotates arm medially
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Teres major Scapula to the humerus Adduct and rotate arm medially Latissiums dorsi From middle of the back, around the side of your body and into the armpit Extend, adduct, rotate arm medially Pull shoulder downward
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Deltoid Thick, triangular muscle that covers the shoulder joint Connects clavicle and scapula to the lateral side of the humerus Abducts arm
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Subscapularis Anterior surface of scapula Connects scapula and humerus Rotate arm medially Teres minor Scapula to humerus Rotates arm laterally
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Biceps brachii Triceps brachii
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Extensor carpi radialis longus Extensor carpi radialis brevis Both extend wrist, abduct hand
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Extensor carpi ulnaris Extends wrist, adducts hand Extensor digitorum Extends fingers Flexor carpi radialis – flexes wrist, abducts hand Flexor carpi ulnaris – flexes wrist, adducts hand
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Rectus abdominus – creates “6-pack” External oblique – outermost layer, wraps around to the back of the body Transversus abdominus – between external and internal oblique Internal oblique – within external oblique Linea alba: band of tough connective tissue down medial line of abdomen
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Deltoid Pectoralis major Biceps brachii Rectus abdominus Transversus abdominus Internal oblique External oblique
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Gluteus maximus Gluteus medius Gluteus minimus
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Tensor fasciae latae Connects ilium to lateral portion of thigh
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http://www.gwc.maricopa.edu/class/bio 201/muscle/leg1.htm http://www.gwc.maricopa.edu/class/bio 201/muscle/leg1.htm
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Hamstring muscles: Biceps femoris (most lateral) Semitendonosis (middle) Semimembranosus (most medial)
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Sartorius – hip to most distal, medial portion of the femur (medial portion of knee)
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Quadriceps femoris group: Rectus femoris Vastus lateralis Vastus medialis Patellar tendon
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Tibialis anterior Gastrocnemius Soleus
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