FROG MUSCLE PHYSIOLOGY 2) What was the smallest voltage required to produce max contraction? What proportion of the muscle fibers in the muscle do you think were contracting to produce this maximal response? Muscle fibers act in response to isolated stimuli in an all or none fashion. However‚ a muscle organ‚ such as the gastrocnemius muscle‚ is composed of many individual muscle fibers. It is known that all of the fibers in a muscle do not have the same threshold and that a stimulus applied to
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Results A left gastrocnemius muscle of a frog (L=3.2cm in situ) was used in experiment 1 and 2‚ while a right gastrocnemius muscle of a frog (L=3.4cm in situ) was used in experiment 3. The sciatic nerve of the frog was placed over the stimulatory electrodes covered with a piece of a Kimwipe moistened with Ringer’s solution. The relationship between muscle length‚ force production and velocity of contraction was studied. Force transduced calibration In order to get a more accurate data from force
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order for a muscle to contract requires a nerve impulse to arrive at the neurotransmitter junction. This then causes a release of acetylcholine (ACh) from the presynaptic terminal. By binding with its receptors on the membrane of the muscle fiber‚ which opens sodium channels generating an action potential that spreads through the length of the fiber‚ stimulating release of calcium from the sarcoplasmic reticulum. Calcium is what activates the contractile mechanism‚ causing the muscle fiber to shorten
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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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efficiency * Muscle fiber type * Higher efficiency in muscles with greater
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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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Unit 2: Physiology Lab Skeletal Muscle Physiology Student Name: Lab Summary Worksheet Directions: Read the following directions before starting the lab. Before starting each lab Activity‚ read the Overview and Introduction. This information will help you understand what you are doing in the lab. You do not have to pdf your lab – the only thing that you will submit for grading is this lab report. You will have to answer the Stop and Think Questions that are embedded in the lab instructions
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Lab 6 Biomechanics of Frog Skeletal Muscle I. Purpose This exercise is designed to demonstrate some mechanical and physiological properties of skeletal muscle using the gastrocnemius muscle of a frog. II. Performance Objectives At the end of this exercise the student should be able to: 1. Define minimal (threshold)‚ subminimal‚ maximal‚ and supramaximal stimulus. 2. Explain what is meant by a “graded” response. 3. Draw a diagram of the setup used in this lab exercise. 4. Calculate the
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Effects of Electrical Stimuli and Injected Reagents on Frog Hearts Melissa Higdon Section 05‚ Group 01 November 19‚ 2013 Introduction: The heart is a very complex muscle for all species. It is responsible for sending oxygenated blood throughout the body as well as sending deoxygenated blood to the lungs‚ and continuously circulate this way for as long as we are alive. Many things can be effected‚ for example how fast the heart beats or how much
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Skeletal Muscle Physiology: Frogs & Human Subjects (1‚ 2‚ 5-8‚ 10-12‚ 14-16) 1. There is a greatr concentration of Na+ f ; there is a greater concentration of K+ e . When the stimulus is delivered‚ the ermeability of the membrane at that point is changed; and c ‚ initiating the depolarization of the membrane. Almost as soon as the depolarization wave has begun‚ a repolarization wave follows it across the membrane. This occurs as b . Repolarization restores the h of the resting cell membrane
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