Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 25% by answering 1 out of 4 questions correctly. 1. During a single twitch of a skeletal muscle Your answer : a. calcium is not released from the sarcoplasmic reticulum. Correct answer: b. maximal force is never achieved. 2. When a skeletal muscle is repetitively stimulated‚ twitches can overlap each other and result in a stronger muscle contraction
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MANY PROCESSES MUST TAKE place within the skeletal muscle fibres in order for muscle contraction to occur. The cross bridge cycle‚ process by which the muscle length is shortened as myosin heads‚ extending from the myosin filaments‚ interact cyclically in a rowing motion with the actin filament (Rayment et al. 1993)‚ is one of the crucial mechanical events required. The mechanism is initiated when an ATP molecule is bound to a myosin head. An enzyme within the head. known as ATPase‚ hydrolyzes the
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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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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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Lab Report Assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions‚ diagrams if needed‚ and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor
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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 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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Title: Muscle twitch response and recruitment‚ summation and tetanus Exercise 1: The effects of nerve stimulation Objectives: 1. To explore the motor and sensory effects of electrical stimuli on a student volunteer‚ using the nerves of the forearm. 2. To examine the position where a largest muscular twich response with the lowest pulse current can be generated. This position is kept constant to determine results in exercises 2 and 3. Procedure: Refer to Human Biology Practical Manual
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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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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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