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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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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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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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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of the bullfrog that was removed at the hip joint through careful dissection of the muscle away from the tibo-fibula bone while leaving the it attached to the knee and heel. The muscle was consistently moistened by Ringer’s solution throughout the entire experiment. The Achilles tendon was removed at the heel of the frog. The tibiofibular bone was cut below the knee and the femur below the knee (Frog Skeletal Muscle Experiement). The baseline value of the force transducer was set to zero. This zeroing
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isolated frog muscle could be made to contract when the sciatic nerve was irritated with a metal object‚ conducted the first muscle experiments between 1661 and 1665. Later‚ between 1737-1798 Luigi Galvani determined that frog muscle responded to electrical currents. The kymograph‚ which was invented in the late 1840’s lead to the revolution of experimental physiology because it enabled muscle contractions to be analyzed and recorded. The muscle cell or fiber is the basic unit of a muscle. The frog gastrocnemius
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REVIEW SHEET NAME_____________________ LAB 6: Skeletal Muscle Physiology Electrical Stimulation 1. Complete the following statements by filling in your answers on the appropriate lines below. A motor unit consists of a (a) and all the (b) it innervates. Whole muscle contraction is a(n) (c) response. In order for muscles to work in a practical sense‚ (d) is the method used to produce a slow‚ steady increase in muscle force. When we see the slightest evidence
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Purpose: The purpose of this lab is to test what substances are necessary for muscle contraction. Hypothesis: Based off the frog muscle immersed separately in Solution A of ATP and distilled water solution‚ Solution B of ATP with KCl in distilled water and MgCl2 in distilled water and solution C of KCl and MgCl2 in distilled water‚ I hypothesize that solution B of ATP with KCl in distilled water and MgCl2 in distilled water will cause the muscle to contract. Introduction: This lab consisted of discovering
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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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