Muscle Contractions By: Evan Contractions‚ put simply‚ are the basic action of any muscle. A contraction is a change in a muscle by which it becomes thickened and shortened after the brain sends signals to nerve cells telling them do contract a specific muscle or muscles. Surprisingly‚ a contraction is a complex human action and reaction‚ yet it is such a breeze to understand the basic meaning of the word. Throughout this essay I will give you extensive details about the process of muscle contractions
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We have three types of muscles in our bodies‚ skeletal‚ smooth and cardiac. Each type of muscle performs different functions in our bodies. Some of the characteristics of our muscles are that they respond to stimuli‚ they are able to shorten in length‚ they stretch when they are pulled and they tend to return to their original shape after contracting or extending them. Muscle contractions occur when our nervous system sends a signal via the neuromuscular junctions the signal arrives at the end bulb
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Q1 Muscle contraction can be understood as the consequence of a process of transmission of action potentials from one neuron to another. A chemical called acetylcholine is the neurotransmitter released from the presynaptic neuron. As the postsynaptic cells on the muscle cell membrane receive the acetylcholine‚ the channels for the cations sodium and potassium are opened. These cations produce a net depolarization of the cell membrane and this electrical signal travels along the muscle fibers. Through
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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 obtained
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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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The muscle physiology of skeletal muscle was observed by using electrical‚ physical‚ and neural stimulations of an isolated gastrocnemius muscle from Rana pipiens. The gastrocnemius receives signals from the action potentials of the sciatic nerve. The muscle contraction is caused by the binding of a neurotransmitter once the action potential reaches the neuromuscular junction. Stimulation of the muscle and the sciatic nerve allows for recording and measuring of these properties. We observed twitch
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1. Discuss the relationship between distribution of muscle fiber type and performance. How might exercise training modify or change a person’s fiber-type distribution? Skeletal muscles contain multiple fiber types that are distinguished by their different myosin ATPase speed‚ and the development of their SR. The two main fiber types are type I and type II fibers. Type II fibers have a faster ATPase and a more developed SR than type I fibers. Type II fibers are also part of a larger motor unit‚
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Microscopic Anatomy and Organization of Skeletal Muscle Skeletal Muscle Cells and Their Packaging into Muscles 1. Use the items in the key to correctly identify the structures described below. g; perimysium c; fascicle Key: a. b. c. endomysium epimysium fascicle fiber myofibril myofilament perimysium sarcolemma sarcomere sarcoplasm tendon 1. 2. 3. 4. 5. 6. 7. connective tissue ensheathing a bundle of muscle cells bundle of muscle cells contractile unit of muscle i; sarcomere d; fiber a; endomysium
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S E 2 Skeletal Muscle Physiology O B J E C T I V E S 1. To define these terms used in describing muscle physiology: multiple motor unit summation‚ maximal stimulus‚ treppe‚ wave summation‚ and tetanus. 2. To identify two ways that the mode of stimulation can affect muscle force production. 3. To plot a graph relating stimulus strength and twitch force to illustrate graded muscle response. 4. To explain how slow‚ smooth‚ sustained contraction is possible in a skeletal muscle. 5. To graphically
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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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