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human muscles
Question | Answer |
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what is the function of the muscular system | body movement maintenance of posture respiration production of body heat communication and constriction of organs and vessels |
Skeletal Muscle | constitutes 40% of body weight are attached to the skeletal system |
Striated Muscle | tranverse bands can be seen in muscle under microscopes |
Contractility | ability for muscles to retract with force |
Excitability | muscles responding to stimuli usually by nerves |
Extensibility | muscles can be stretched |
Elasticity | when muscles recoil to their original resting length after being stretched |
structual parts | epimysium fascia muscle fasciculi perimysium muscle cells endomysium sarcoplasm myofibril actin myofilaments troponin tropomyosin myofilaments myosin sarcomeres Z disk I band A band H zone M line sarcolemma tranverse T tubes Sarcoplasmic Reticulum |
Membrane potential | the charge difference from the outside and inside of the cell membranes |
Motor Neurons | nerve cells that carry action potentials to skeletal muscle fibers |
Muscular junction or Synapse | a junction between a neuron and a muscle fiber or effector cell |
Presynaptic Terminal | the enlarged axon terminal |
Synaptic Cleft | the space between the presynaptic terminal and the muscle fiber |
Postsynaptic terminal | muscle fiber membrane that contains many vesicles |
Acetycholinesterase | the enzyme that breaks down acetylcholine, in the synaptic cleft |
Acetycholine | ACH, functions as a neurotransmitter, inhabits a postsynaptic cell |
Neurotransmitter | a molecule released by a presynaptic cell that stimulates or inhibits a postsynaptic cell |
Sliding Filament Mechanism | the sliding of actin myofilaments past myosin myofilaments during contraction |
Cross-Bridges | when the actin myofilament binds to the heads of myosin myofilaments |
Rigor Mortis | when a person dies and the ATP is not available, so the cross bridges arent released, causing muscles to stiffen |
Muscle twitch | a contraction of an entire muscle in response to a stimulus that causes action potentials |
Threshold | level when the stimulus strength is strong enough to produce an action potential |
All or None response | when a muscle fiber contracts maximally |
contraction phase | the time when the muscle is actually contracting |
Relaxation phase | when the muscles relax |
tetanus | when muscle remains contracted between stimuli without relaxing |
Recruitment | the increase in the number of motor units being activated |
Creatine phosphate | high energy molecule that is used rapidly to maintain adequate ATP in contracting muscles |
Anaerobic Respiration | occurs in the absence of oxygen and results in breaking down of glucose to get ATP and lactic acid |
Aerobic Respiration | requires oxygen and breaks down glucose to get ATP water and carbon dioxide |
Muscle Fatigue | when ATP is used during muscle contraction faster then it can be removed |
Physiological Contraction | when muscles can't contract or relax because of extreme muscle fatigue |
Psychological Fatigue | most common type of fatigue, involves central nervous system, but person perceives that they cant contract muscle any more |
Muscle tone | refers to constant tension produced by muscles of the body over long periods of time |
slow and fast twitch fibers | differences in rod portion of myosin myofilament, slow twitch fibers have type 1 myosin and fast have either type IIa or IIx myosin |
Myoglobin | supplies richer blood, it stores oxygen temporarily and releases oxygen even when the blood flow is interrupted |
Smooth Muscle | small and spindle shaped, usually one nucleus per cell, organized to form layers and have gap junctions found in hollow organs and glands and is involuntary |
Cardiac Muscle | long straited and branching found in heart and single central intercalated disks, involuntary |
Tendon | it is what connects muscle to bone, |
Origin | AKA the head, most stationary end of the muscle |
Insertion | the end of muscle that is attached to the bone undergoing the greatest movement |
Antagonist | a muscle working in opposition to another muscle |
Synergists | muscles that work together to cause movement |
Prime Mover | the one muscle that plays the major role in accomplishing the desired movement |
Fixator | are muscles that hold one bone in place relative to the body while a usually more distal bone is moved |