Skeletal Muscle Lab Introduction: Motor neurons and muscle fibers are the building blocks of motor units and where they intersect is called the neuromuscular junciton. The region where the flattened end of a motor neuron transmits neural impulses to a muscle is the motor end-plate. The end plate potentials depolarizes skeletal muscle fibers caused by neurotransmitters binding to the postsynaptic membrane in the neuromuscular junction. The process of contraction of the muscle cell is called excitation-contraction
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2017 Motor Unit Recruitment and Muscle Fatigue Lab Introduction Human skeletal muscles are made up of hundreds of cylindrically-shaped cells called myofibers‚ and they are bound together by connective tissue. These muscles are stimulated to contract by somatic motor nerves‚ or motor neurons‚ that carry signals in the form of nerve impulses from the brain or spinal cord‚ to the skeletal muscles. Although a motor neuron can innervate several fibers‚ each muscle fiber can only be innervated by one
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Stimulus-Dependent Lab A motor unit is a motor neuron and the muscle fiber it controls. A whole muscle is made up of hundreds of motor units that are handled by different motor neurons that react at different levels of stimulation. The electric shock acts as an action potential by changing the membrane permeability allowing the sodium and potassium ions to pass through. At different levels of stimulation the motor neurons stimulate a motor unit and the more stimulation the more motor units become
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Lab 3 – Skeletal Muscle Physiology Introduction Skeletal muscles are composed of hundreds to thousands of individual cells‚ each doing their share of work in the production of force. As their name suggests‚ skeletal muscles move the skeleton. Skeletal muscles are remarkable machines; while allowing us the manual dexterity to create magnificent works of art‚ they are also capable of generating the brute force needed to lift a 100-lb. sack of concrete. When a skeletal muscle from an experimental
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Lab 6: Amphibian Muscle Contraction Results: For this experiment‚ Isometric contractions of the gastrocnemius muscle of a frog were analyzed and from this data the latent period‚ twitch‚ motor unit summation‚ tetanus‚ fatigue & mechanical summation were measured. The data was used to quantify the effect of passive tension on the twitch force‚ effect of stimulus intensity on the twitch force‚ effect of stimulus frequency on contractile force of xenopus gastrocnemius muscle. The threshold voltage
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Repeat this procedure for 10‚ 15‚ and 20 g added to the weight hanger. 6. To determine the force‚ F‚ needed to displace the spring‚ measure each of the slotted masses‚ individually‚ then convert the sum of the added masses to a weight in dynes (see lab manual for conversion). 7. The extension of the spring‚ x‚ is found by subtracting the vertical scale reading in each case from the equilibrium position reading. 8. Plot a graph with the added weight‚ F‚ on the vertical axis and the extension
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Laboratory – Muscle Physiology A. MUSCLE TONUS Observations‚ Report and Conclusion: A. Define muscle tonus and give its importance * Muscle tonus refers to a state of slight muscular contraction maintained by synchronous impulses of low frequency‚ discharged by the spinal motor neurons. * Reflex in nature. * Muscle tonus is a small amount of tension in the muscle due to weak‚ involuntary contractions of its motor units. Muscle tonus is important in a sense that it governs the
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Background Information Muscles in the human body can be classified into three different types- cardiac‚ smooth and skeletal muscles. The skeletal muscles are the muscles that can be controlled voluntarily‚ in things such walking and picking things up. The skeletal muscles are made up of bundles of muscle fibres (which are also known as myofibrils‚ as can be seen below). Each of the muscle fibres contain many sarcomeres‚ which is the most basic form of striated muscle tissue- they consist of two
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Abstract The purpose of this experiment was to use the muscle tension and the electrical activity in the dominant and non-dominant forearm muscle‚ the flexor digitorum superficialis‚ to analyze the determinants of muscle tension and fatigue‚ and the reasons as to why differences may occur between the dominant and non-dominant arm. The generation of tension in a muscle is determined by the major type of motor unit being recruited‚ as well as the rate in which action potentials are being fired. A subject
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muscle contraction Introduction For a skeletal muscle fiber to contract‚ a stimulus must be applied to it. The stimulus is delivered by a nerve cell‚ or neuron. A neuron has a threadlike process called and axon that my run 91 cm or more to a muscle. A bundle of such fibers from man different neurons composes a nerve. A neuron that stimulates muscle tissue is called a motor neuron. The motor neuron branches into terminal structures called telodendria that come into close approximation with
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