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Reflect back on the Muscle Fatigue investigation we did earlier in this Activity. Choose one of your classmate’s interpretation to one of these questions: What happened to your energy & ability to pinch the clothespin as you progressed through each trial? Why?  What might cause one to be able to get more squeezes, in other words, to have less fatigue? Explain in terms of biological concepts. Suggest how the amount of ATP produced cause your muscle cells to be less efficient. When did this change in the amount of ATP produced occur in this investigation? How could you tell? Your muscles would probably recover enough after 10 minutes to operate at the original efficiency. Explain why.  Show how specific details from the steps of cellular respiration add details to answer this question.

Muscle Contraction In an experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with one muscle fibre is observed in this experiment. One end of the muscle fibre is attached to a mass. The following data were obtained from the experiment. Analyze the data and answer the following questions. Number of Trials Strength of Stimulus (mV) Mass Lifted by Muscle Contraction (g) 1 20 2 40 3 60 50 4 80 50 100 Not Tested 120 50 *note that the voltage applied is positive in order to raise potential from resting to threshold Identify the manipulated, responding and controlled variables in the experiment described above. Strength of Stimulus Number of Muscle Fibre Stimulated Mass Lifted by Muscle Contraction

* The figure below is called the It shows the amount of tension generated by a muscle and the force of contraction depends on how stretched or contracted it was before it was stimulated. * 100 80 (d) 60 (e) Normal /range 40 (a) 20 1.2 μm 1.6 μm 2.1 μm 2.2 um 2.6μm 3.6 μη Decreased length Increased length Optimal resting length Tension (percent of maximum)

Muscle Contraction In an experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with one muscle fibre is observed in this experiment. One end of the muscle fibre is attached to a mass. The following data were obtained from the experiment.  Number of Trials  Strength of Stimulus (mV)  Mass Lifted by Muscle Contraction (g)  1  20  0  2  40  0  3  60  50  4  80  50  5  100  Not Tested  6  120  50 *note that the voltage applied is positive in order to raise potential from resting to threshold Identify the manipulated, responding and controlled variables in the experiment described above. Strength of Stimulus   Number of Muscle Fibre Stimulated   Mass Lifted by Muscle Contraction

Fatigue is not well understood. Some factors that have been proposed to explain the fall in force duringfatigue include: changes in the 'sense of effort', loss of 'central drive', failure of neuromuscular propagation, reduction in calcium release in excitation- contraction coupling, metabolic changes in the muscle, and reduction in muscle blood flow owing to compression of blood vessels. 1. Do your experiments help to decide which factors are important?

What are the two types of muscle movement categories? Give an example for both. E. Describe Swammerdam's experiment and Galvani's experiment with frog legs. What did they tell us about muscl contraction? 3. What is the sliding-filament model for muscle contraction? Describe the role of actin and myosin of sarcomeres in the model (be specific). 4. Describe how an action potential triggers muscle contraction. Know the specific molecules involved. 5. Describe the structural and functional differences between smooth, cardiac and skeletal muscles. What are the three types of skeletal muscle fibers and how do they differ in structure and function? Next « Previous MacBook Pro

Human Anatomy & Physiology I (BIO168) Sequence of Events for Muscle Contraction Practice Worksheet   See if you can place the events that occur during muscle contraction and relaxation in their proper order.  Insert numbers in the paces provided to order the events in the proper sequence.    _____   A.  An electrical impulse travels over the sarcolemma and inward along the T-tubules, causing sacs in the sarcoplasmic reticulum to release calcium. ____   B.  The release of ACh stops and acetylcholinesterase breaks down any remaining ACh. _____   C.  Troponin and tropomyosin prevent the myosin heads from grasping the thin  filament, and the muscle fiber relaxes. _____   D.  An electrical impulse causes small vesicles at the end of a motor neuron to release the neurotransmitter acetylcholine (ACh). _____   E.  Calcium binds with the troponin on the actin filament, exposing attachment points. _____   F.  ACh diffuses across the synaptic cleft, where it stimulates receptors in the…

We move a lot and do not even realize how intricate these movements may be from gross motor to fine motor manipulations. Briefly explain the steps involved in a single muscle contraction beginning at the neuromuscular junction through one complete contraction and relaxation for the sliding filament theory. Don’t forget to include all the major proteins (actin, myosin, troponin and tropomyosin) involved as well as calcium and ATP.

First, explain how resting membrane potential is established in terms of ion concentration and electric charge. Next, explain the process of neural signal transmission from an alpha motor neuron to the muscle fiber. Do this by explaining how an AP is generated (ions and membrane proteins) at the neuron, how the signal is propagated, what happens at the axon terminal, what happens at the motor endplate, and explain all the molecular events that occur to cause muscle contraction.

Drug X blocks ATP regeneration from ADP and phosphate. How will muscle cells respond to this drug?a. by absorbing ATP from the bloodstreamb. by using ADP as an energy sourcec. by using glycogen as an energy sourced. none of the above

Define the all-or-none principle. The same student remarked that at 180 mV stimulus, it is expected that 100 g mass is lifted by the muscle fibre. Do you agree or disagree? Why or why not?

a.  Define the all-or-none principle. b.  The same student remarked that at 180 mV stimulus, it is expected that 100 g mass is lifted by the muscle fibre. Do you agree or disagree? Why or why not?

Conflicting Claims About the Effect of Exercise on the Rate of Clothespin Squeezing Student A claims that a person will be able to squeeze a clothespin more times in a minute if the person exercises first. Student A suggests that exercising produces a faster pulse rate, which indicates that the blood is getting to the muscles faster. Student B claims that a person will be able to squeeze the clothespin more times in a minute if the person does not exercise first. Student B suggests that exercise takes energy away from the muscles, and a person who has been resting will have more energy. Which of the two students do you agree with? How could you find out for sure which claim is correct ?

If you were able to control fatigue in the muscle cell experimentally such that you only exposed the muscle to high levels of Pi and no other metabolites, what would you observe? A decline in force without much change in velocity A decline in velocity without much change in force A muscle operating below Lo A decline in both force and velocity An increased affinity of Ca2+ for troponin

96. An investigator is studying the contraction and relaxation of vascular smooth muscle in an experimental animal model. Which of the following describes the most likely order of events during this process? 0000000 200602 H) Myosin Light Chain Phosphorylation 1 2 2 3 3 4 4 Binding of Calcium to Calmodulin 3 1 4 2 4 2 3 Myosin Light Chain Dephosphorylation 2 3 4 3 4 2 1 2 Calcium Entry Into the Cell 4 2 3 1 1 1 3 1

2. We discussed how muscle spindles allow for precision of movement as a muscle lengthens, and particular muscles which require more precise movements will contain more spindles. In addition to this precision control over muscle length, there are other differences between muscles which enable more precision in how much force is generated. Consider the two graphs below which depict force generated by two different muscles as additional motor units are recruited. Force Muscle A Load Force Muscle B Load a) Describe why the first steps for a low force contraction in both muscles are smaller than the later ones in the context of motor units and force production.

In your conclusions discuss what else EMG analysis could be used for in rehabilitation as well ashow the concepts of fatigue and myoelectric thresholds should be incorporated into FES system design.

What false about Henneman's size principle? Select one: a. The relative change in force remains relatively constant b. Minimizes the amount of fatigue C. Motor units are recruited from smallest to largest d. Low force recruited first e. Fast twitch recruited first

Know the Sliding Filament Theory & neurological events leading up to contraction. (i.e. from the impulse to relaxation).  Can you outline how an electrical signal is transmitted from the neuron to the muscle?  What is meant by the term “excitation-contraction coupling?”

In an experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with one muscle fibre is observed in this experiment. One end of the muscle fibre is attached to a mass. The following data were obtained from the experiment.  Number of Trials  Strength of Stimulus (mV)  Mass Lifted by Muscle Contraction (g)  1  20  0  2  40  0  3  60  50  4  80  50  5  100  Not Tested  6  120  50 Is the threshold potential for this muscle fibre exactly 50 mV. Do you agree or disagree? Explain.

Part B Matching Choose the appropriate words or phrases from column "B" that match the terms in column "A." Words or phrases in column "B" may only be used once. Column B Column A 13. Elasticity A. Every one fires B. Binds muscle fibres together 14. Neuromuscular junction C. Muscle's ability to stretch 15. Myosin D. Attaches to troponin 16. Perimysium E. Has a "head and tail" 17. Neurotransmitter Sarcolemma F. Acetylcholine 18. G. muscle membrane 19. Calcium H. Where nerve contacts muscle 20. All-or-none-principle

Now in your own words, EXPLAIN (1) howa neural impulse is transferred to a muscle cell this is the process of “muscle excitation"), and (2) how the electrical impulse travels into he T-tubules and causes calcium to be released from the sarcoplasmic retículum (this is the process of “excitation-contraction coupling"): OMADidoinos reticulum 5. se mo S1e hosph erah anism

3.4. About human skeletal muscle contraction, what are the correct statements? PHYSIOLOGY_basic (OJO) A muscle fiber is made by the parallel apposition of sarcomers. Generation of force relies on the formation of cross-bridges between actin and myosin filaments. In the process of contraction, adenosine triphosphate (ATP) is required both to drive the actin-myosin association-dissociation cycle and to recycle calcium back to the endoplasmic reticulum. Each muscle fiber is innervated by one neuron only. T tubules are plasma membrane invaginations of the sarcolemma that allow excitation-contraction coupling.

1. What are the two types of muscle movement categories? Give an example for both. 2. Describe Swammerdam's experiment and Galvani's experiment with frog legs. What did they tell us abc ard contraction? 3. What is the sliding-filament model for muscle contraction? Describe the role of actin and myosin of sarcc the model (be specific). 4. Describe how an action potential triggers muscle contraction. Know the specific molecules involved. 5. Describe the structural and functional differences between smooth, cardiac and skeletal muscles. What are ardings ine E- three types of skeletal muscle fibers and how do they differ in structure and function? Library arly Alert « Previous Next MacBook Pro

Determine the isoelectric point of myofibrillar proteins here in this experimental data

How does the activation of vertebrate skeletal muscle differ from the activation of arthropod muscle fibers?   comments : please give me answer precise and best of your knowledge. thanks