myofibrils are composed of two types of even tinier structure‚ the myofilaments. The thick myofilaments called myosin filaments consist mainly of the protein myosin. The actin filaments consist of the protein actin. Myosin and actin filaments are arranged lengthwise in the muscle fibers so that they overlap. During muscle contaction‚ the actin filaments are pulled inward between the myosin filaments. As that occurs; a nerve cell that stimulates a muscle releases a compound known as acetylcholine.
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unit of contraction with actin and myosin and z-lines on each side. Calcium binds to the troponin protein‚ located on the actin filament. This allows tropomyosin to move‚ exposing the myosin head binding sites on actin. When the myosin heads bind to actin‚ this is known as the cross bridge. ADP and Pi molecules are released‚ causing myosin to pull on actin. This movement is known as the power stroke. To stop the contraction‚ ATP binds to the myosin head‚ and myosin detaches from actin‚ stopping the
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happens to muscle force production at extremes of length (too short or too long). (Hint: Think about sarcomere structure and actin and myosin interactions) Muscle too short: _Muscle force produced is reduced and they lose their strength as they cannot contract.___ Muscle too long: _Muscle force production is reduced because of insufficient overlap of actin and myosin. There isn’t maximal cross bridge formation.___ Terms 6. Select the LETTER of the condition from column B that most correctly
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The Muscular System: Neuromuscular Junction 1. What insulates each muscle cell? __________endomysium_______________ 2. Synaptic vesicles in the axon terminal of a motor neuron contain what neurotransmitter? __________acetylcholine_______________ 3. An action potential in the axon terminal of a motor neuron opens what type of ion channels? ____________Voltage-gated Calcium_____________ 4. By what means of membrane transport does the neurotransmitter leave the axon
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Kleinert Name ____Brittany Ciupka_________ Case Studies – Unit #3 – 15 points (part of Exam #3 score) This assignment is due Monday‚ November 5th by midnight. -2 points will be deducted for each day it is late. Reminder : assignment must be submitted via Blackboard. It will not be accepted via e-mail or hard copy. Please let me know if you need a tutorial on how to submit via Blackboard. A 17-year-old male was working vigorously on a summer construction crew building a new section
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Chaper 11 1. Define responsiveness‚ conductivity‚ contractility‚ extensibility‚ and elasticity. State why each of these properties is necessary for muscle function. a. Responsiveness- is a property of all living cells- Muscle and nerve cells have developed this property to the highest degree. When stimulated by chemical signals‚ stretch‚ and other stimuli‚ muscle cells respond with electrical changes across the plasma membrane. b. Conductivity- Stimulation of a muscle cell produces
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myofibril‚ myofilaments; Small(+) Endomysium: Thin connective tissue investing each muscle cell. Epimysium: Connective tissue ensheathing the entire muscle. Fascicle: A discrete bundle of muscle cells. Fiber: A muscle cell. Myofilament: Actin- or myosin- containing structure. Perimysium: Connective tissue surrounding a fascicle. Sarcolemma: Plasma membrane of the muscle cell. Sarcomere: Contractile unit of a muscle. Tendon: Cordlike extension of connective tissue beyond the muscle‚ serving to
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I. Types of Muscles a. Skeletal i. Striated ii. Uses intracellular calcium to contact iii. Big cylindrical cells iv. Multi-nucleated v. Voluntary vi. Location: attached to the bone vii. Used for locomotion b. Cardiac i. Involuntary ii. Uni-nucleated iii. Striated iv. Location: walls of heart v. Used to propel blood vi. Uses extracellular calcium c. Smooth i. Involuntary ii. Location: Walls of hallow organs iii. Non-striated iv. Uses extracellular calcium v. Spindle shaped cells
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Lab 4: Skeletal Muscle Function Exercise 5: The Length-Tension Relationship Materials and Methods In this experiment I used a frog anesthetized with ms222. The frog’s skin is cut and removed from both the legs‚ the Achilles tendon is cut and the tendon and calf muscle are removed from the lower legs. The femur muscle is also cut. Attached to the legs are femur clamps which are connected to the transducer arm‚ stimulation electrodes are then positioned against the muscle. I plugged the output
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Dennervation hypersensitivity damage to the ANS increases the effector response to stimulation Ganglia a cluster of nerve cell bodies that lie outside the CNS Mass activation Divergence-Preganglionic fibers branch to synapse with numerous postganglionic fibers (up‚ down‚ level) Convergence-Postganglionic fibers receive input from numerous preganglionic fibers Sympathetic system is activated as a unit Sympathoadrenal System the closely related functioning adrenal medulla and sympathetic nervous
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