Muscle Conduction Lab Report

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Purpose: The purpose of this experiment is to demonstrate neuromuscular conduction through analyzing nerve and muscle action potentials and its electrical properties (EMG and muscle force). In this lab, relative strength and electrical activity will be determined in the dominant and non-dominant forearm muscles of both subjects. Grip strength of the subjects will be measured by using a hand dynamometer and recorded EMGs. The Achilles tendon reflex will also be studied in this experiment, assessing evidence of conduction times and nerve velocities in the coordination of the motor activity. Hypothesis: Introduction/Background: A myofibril or muscle fiber is made up of thick and thin filaments. Myosin makes up the thicker filament and the…show more content…
The bodies of these motor neurons are located in the ventral horn of the gray matter of the spinal cord. These motor neurons and muscle fibers combine to form a motor unit and once innervated, groups of motor units coordinate to perform a muscle contraction. “Although each skeletal muscle is innervated by one motor neuron, each motor neuron innervates more than one muscle fiber….” The motor unit must reach a threshold in order for an action potential to occur and once fired the muscle fibers contract to its maximum and in unison verify the of “all or none” principle. The size and function of the muscle determine how many muscle fibers a single motor neuron will innervate. Larger muscles have hundreds of muscle fibers in a single motor unit whilst a smaller muscle used for fine movement (ex. Eye) is innervated by a lot of…show more content…
The space, which lies between the presynaptic and postsynaptic terminals, is known as the synaptic cleft. The synaptic cleft contains a thin layer of connective tissue in which extracellular fluids diffuse to off send signals. Synaptic conduction involves the release of acetylcholine to transmit neural information to muscle fibers in a response of a contraction. Presynaptic terminals contain high levels of acetylcholine synaptic vesicles that fuse with the terminals to deposit the Ach into the synaptic cleft. The time for the release of acetylcholine accounts for the synaptic delay of approximately 0.3seconds. After acetylcholine diffuses and binds to receptors, the concentration of membrane permeability increases allowing positive ions to diffuse with facilitation. Once permeable, Na+ ions will diffuse into the fiber, depolarizing the membrane and will eventually assist the end plate potential to attain threshold and if the threshold is great muscle will contract. Choline and acetate are hydrolyzed in the basal lamina by the enzyme acetyl-cholinesterase. The process of hydrolysis interchangeably happens before or after acetylcholine has bounded to
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