LABORATORIO DE SIMULACIÓN (Physioex 9.0).Ejercicio Nº 2: FISIOLOGÍA DEL MÚSCULO ESQUELÉTICO-ACTIVIDADES DEL 1 AL 7. ALUMNO: ANTHONY HUAMÁN ALAYO COD: 20120353 CURSO: FISIOLOGÍA DE ANIMALES DE GRANJA-LABORATORIO GRUPO: A CICLO: 2015-I Exercise 2: Skeletal Muscle Physiology: Activity 1: The Muscle Twitch and the Latent Period Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1. Skeletal muscles are connected to bones by You correctly answered: b. tendons. 2. Skeletal muscles are composed of hundreds to thousands of individual cells called You correctly answered: c. fibers. 3. The term motor unit refers to You correctly answered: c. one motor neuron and all of the skeletal muscle fibers it innervates. 4. The motor neuron and muscle fiber intersect at what is called You correctly answered: d. the neuromuscular junction. 5. A twitch is You correctly answered: a. one contractile response to a single action potential. 04/18/15 page 1 Experiment Results Predict Question: Predict Question: Will changes to the stimulus voltage alter the duration of the latent period? Your answer : b. No, changing the stimulus voltage will not change the latent period duration. Stop & Think Questions: What is the period of time that elapses between the generation of an action potential and the start of muscle tension development in a muscle fiber? You correctly answered: c. the latent period What occurs during the latent period of these isometric contractions? You correctly answered: b. All the steps of excitation-contraction coupling occur. Experiment Data: Voltage 0.0 3.0 4.0 6.0 8.0 10.0 Length 75 75 75 75 75 75 Active Force 0.00 1.04 1.32 1.65 1.81 1.82 Passive Force 0.00 0.00 0.00 0.00 0.00 0.00 04/18/15 page 2 Total Force 0.00 1.04 1.32 1.65 1.81 1.82 Latent Period ----0.40 ---------- 04/18/15 page 3 04/18/15 page 4 or muscle tension. An action potential in a motor neuron triggers the release of which neurotransmitter? You correctly answered: b.Post-lab Quiz Results You scored 100% by answering 7 out of 7 questions correctly. mounted skeletal muscle induces the development of muscle force. an individual skeletal muscle cell. Which of the following statements concerning this observation is true? You correctly answered: c. hyperpolarization phase 5. The electrical stimulus mimics acetylcholine release at a neuromuscular junction 04/18/15 page 5 . one contractile response to a single action potential. an EPP (end-plate potential). the contraction phase: the time between the end of the latent period and peak muscle tension 7. Which of the following correctly matches the twitch phase with its definition? You correctly answered: d. A sufficiently strong electrical stimulus applied to an isolated. The graded depolarization in the skeletal muscle fiber that is elicited in response to one action potential from the motor neuron is called You correctly answered: c. 1. acetylcholine 2. The term skeletal muscle fiber refers to You correctly answered: a. 4. 6. A skeletal muscle twitch is You correctly answered: a. Which of the following is not a phase of a skeletal muscle twitch? You correctly answered: b. 3. El efecto neto de este acoplamiento es la vinculación de la concentración de calcio libre en el citosol. 3. -Periodo de latencia: Es el tiempo que transcurre entre la generación de un potencial de acción en la célula muscular y el comienzo de la contracción del músculo. con el fin de conseguir una respuesta de movimiento. inicia una contracción breve. -Estimulo eléctrico: Es la aplicación de electricidad en muy poco o reducidos voltaje. La acetilcolina se una a la proteína receptora postsinaptica. su regulación puede ser voluntaria y está controlada por el sistema nervioso somático. músculos. El potencial de acción que se inicia en la placa motora. denominada contracción fasica. 04/18/15 page 6 . tienen muchos núcleos dispuestos periféricamente pudiendo considerarse un sincitio.Review Sheet Results 1. and latent period. nervios. cuyo origen es la fusión de mioblastos. En la placa motora. En el músculo esquelético esta despolarización permite la entrada de calcio. puede generar un PA en la fibra muscular postsinaptica. Your answer: Definiciones: -Fibra muscular esquelética: Son células musculares estriadas. -Contracción del musculo esquelético: Es la fase que comienza al final del período de latencia y termina cuando el músculo alcanza la máxima tensión. un solo potencial de acción (PA) de la motoneurona. en partes del cuerpo. Your answer: Acoplamiento entre excitación y contracción: La llegada de un potencial de acción a los terminales de los axones motores causan la liberación de acetilcolina en la moto-neurona. 2. se propaga en ambas direcciones. y en el músculo liso activa un mensajero secundario que se une a receptores en el retículo endoplasmático y así éste libera el calcio necesario para la contracción muscular. motor unit. Describe the process of excitation-contraction coupling in skeletal muscle fibers. skeletal muscle twitch. What is the role of acetylcholine in a skeletal muscle contraction? Your answer: La acetilcolina es un neurotransmisor. excitando así toda la membrana de la fibra muscular y poniendo en marcha la secuencia de acontecimientos que conducen a la contracción. electrical stimulus. intracelularmente se producen cambios químicos (incluyendo la liberación de calcio desde el retículo sarcoplásmico) que conducen a la contracción. Durante este periodo de latencia se produce el acoplamiento excitación-contracción. -Unidad motora: Es la que emite el impulso que en último término hace que la fibra muscular se contraiga lo que quiere decir que conduce los impulsos del cerebro y la médula espinal hacia los efectores (músculos). Aunque no se genera ninguna fuerza durante el período de latencia. con un PA de la membrana plasmática de la fibra muscular. Define the terms skeletal muscle fiber. transcurren varios milisegundos entre el instante en que se inicia el PA y el comienzo de la contracción. lo que hace a esta sinapsis cuantitativamente distinta de muchas sinapsis entre neuronas. siempre que se propaga un PA en una fibra muscular. abriendo los canales iónicos de la fibra muscular. cuando se libera en la unión neuromuscular produce una despolarización del músculo. porque el estimulo ya llego al umbral que se nesecitaba para abrir los canales ionicos. La fase de relajación Es el período de tiempo desde la tensión máxima hasta el final de la contracción del músculo. desplazará el potencial de membrana hacia la despolarizacion. Aunque no se genera ninguna fuerza durante el período de latencia. Período de latencia Es el tiempo que transcurre entre la generación de un potencial de acción en la célula muscular y el comienzo de la contracción del músculo. Describe the three phases of a skeletal muscle twitch. 2.4. 6. do sodium ions start to move into or out of the cell to bring about the membrane depolarization? Your answer: la sustitución de algunos de sodio por potasio en el liquido extracelular que baña una celula excitable. Your answer: son 3 fases: 1. 04/18/15 page 7 . fase de contracción Comienza al final del período de latencia y termina cuando el músculo alcanza la máxima tensión . intracelularmente se producen cambios químicos (incluyendo la liberación de calcio desde el retículo sarcoplásmico) que conducen a la contracción. 3. At the threshold stimulus. Does the duration of the latent period change with different stimulus voltages? How well did the results compare with your prediction? Your answer: el periodo de latencia no cambia con un incremento de voltaje porque. 5. A single action potential propagating down a motor axon results in You correctly answered: d. 4. the cellular events involved in excitation-contraction coupling occur. 04/19/15 page 1 . During the latent period for an isometric contraction You correctly answered: c. motor neurons. 2. In resting skeletal muscle. a single action potential and a single contractile event in the muscle fibers it innervates. the sarcoplasmic reticulum. Skeletal muscle fibers are innervated (stimulated) by You correctly answered: c. 1. calcium is stored in You correctly answered: c. 3.Exercise 2: Skeletal Muscle Physiology: Activity 2: The Effect of Stimulus Voltage on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 66 0. 0.0 volt up to 10 volts.00 0.0 6.74 1.0 2.8 volts 12.5 4.82 1. What is the lowest stimulus voltage that induces active force in the skeletal muscle? You correctly answered: b.70 1.0 0.81 1.5 3.65 1.82 1.82 1.00 0.00 page 2 Total Force 0.59 1. what will happen to the amount of active force generated with each stimulus? Your answer : c.19 1.82 1.5 8.00 0. The active force will first increase and then plateau at some maximal value as the stimulus voltage increases.5 6.82 1.32 1.5 9. Stop & Think Questions: What do you see in the active force display when the stimulus voltage is set to 0.0 Length 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 Active Force 0.5 10.00 0.00 0.0.00 0.0 8.5 7.00 0.Experiment Results Predict Question: Predict Question: As the stimulus voltage is increased from 1.00 0. Enter the threshold voltage for this experiment in the field below and then click Submit to record your answer in the lab report You answered: 0. Enter the maximal voltage for this experiment in the field below and then click Submit to record your answer in the lab report.00 0.87 1.00 0.8 1.00 0.00 0.00 0.00 0.74 1.00 g.04 1.43 0.51 1. You answered: 10 volts Experiment Data: Voltage 0.78 1. threshold voltage 6.32 1.66 0.00 0.0 5.00 0.5 5.2 0.87 1.04 1.00 0.00 0.0 7.0 4.82 .70 1.43 0.42 1.59 1.00 0. there was no activation of skeletal muscle fibers by this stimulus.42 1.02 0.0 1.78 1.82 1.15 0. and why does this observation make sense? You correctly answered: a.0 3.00 0.81 1.02 0.65 1.00 0.15 0.19 1.82 04/19/15 Passive Force 0.00 0.0 9.00 0.5 2.00 0.00 0.51 1. 04/19/15 page 3 . 04/19/15 page 4 . 04/19/15 page 5 . 04/19/15 page 6 . 04/19/15 page 7 . 04/19/15 page 8 . 04/19/15 page 9 . 04/19/15 page 10 . You correctly answered: d. threshold voltage 4.Post-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 3. Motor unit recruitment refers to You correctly answered: a. they were all successfully recruited). Why was a maximal voltage observed in this experiment? You correctly answered: b. maximal voltage 5. 1. activation of cross bridge cycling via increased intracellular calcium levels. the ________ is the amount of stimulus required to successfully recruit all the muscle fibers into developing active force. The ________ is the minimal stimulus needed to cause a depolarization of the muscle plasma membrane (sarcolemma). By definition. You correctly answered: c. all the muscle fibers contained in this muscle are depolarized and they all develop active force (that is. Active tension (or force) in a skeletal muscle fiber results from You correctly answered: a. At the maximal voltage. 04/19/15 page 11 . an increase in the number of active muscle fibers to increase the force developed in a muscle. 2. más fibras musculares se activan y por tanto mayor será la fuerza producida por el músculo. se aumento el voltaje hasta 10. what happened to the muscle force generated with stronger electrical stimulations and why did this change occur? How well did the results compare with your prediction? Your answer: Si se incrementa el voltaje del estímulo por encima del umbral. a partir de ahi. también aumenta la cantidad de fuerza producida por el músculo entero.5. 3.82. 2. La máxima fuerza en el músculo entero se produce cuando todas sus fibras musculares han sido activadas por un estímulo suficientemente grande (denominado voltaje máximo). Este resultado se produce porque. 04/19/15 page 12 . todas las fibras musculares se activaron generando una fuerza de 1.8 hasta 8. de ahi en adelante. What happened in the isolated skeletal muscle when the maximal voltage was applied? Your answer: cuando se aplico la tension maxima 8.5. Describe the effect of increasing stimulus voltage on isolated skeletal muscle. cuanto mayor es el estímulo que recibe un músculo.Review Sheet Results 1. How is this change in whole-muscle force achieved in vivo? Your answer: en el experimento se logra aumentando el estimulo de voltaje desde 0.0 pero la fuerza generada ya no aumento debido a que todas las fibras musculares ya estaban activadas. Specifically. La estimulación con voltajes superiores al voltaje máximo no aumentarán la fuerza de contracción ya que todas las fibras musculares han sido activadas. los estimulos que se dan a pesar de ser más fuertes no logran resultado debido a que ya no hay más fibras celulares que activar. wave summation. During a single twitch of a skeletal muscle You correctly answered: b. Wave summation increases the force produced in the muscle. twitches can overlap each other and result in a stronger muscle contraction than a stand-alone twitch. maximal force is never achieved. Another way to increase the force produced by a muscle is to You correctly answered: d. When a skeletal muscle is repetitively stimulated.Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. Wave summation is achieved by You correctly answered: a. increase the number of activated motor units. increasing the stimulus frequency (the rate of stimulus delivery to the muscle). 4. This phenomenon is known as You correctly answered: c. 04/19/15 page 1 . 1. 2. 3. 83 4.83 1. do you think you will need to increase the stimulus voltage? Your answer : a. As the stimulus frequency increased.45 4.83 1.5 8.Experiment Results Predict Question: Predict Question 1: As the stimulus frequency increases. Yes.64 5. Yes.5 8.45 4. Predict Question 2: In order to produce sustained muscle contractions with an active force value of 5.00 0. yes Stop & Think Questions: Was there any change in the force generated by the muscle during the second stimulated twitch? You correctly answered: c.5 8.83 1.00 0. As the stimulus frequency increases. Is the total muscle force generated by the higher frequency stimulation greater than the force generated in previous stimulations? You correctly answered: a. it is greater than the previous stimulations.00 0.5 Length 75 75 75 75 75 75 Stimulus Single Multiple Multiple Multiple Multiple Multiple 04/19/15 Active Force 1. Does the force generated by the muscle change with each additional stimulus? You correctly answered: b.83 4.00 Total Force 1.5 10 8.00 0. and a limiting maximum value was observed. the muscle force generated by each successive stimulus will first increase and then decrease as the stimulus frequency becomes very high. what will happen to the muscle force generated with each successive stimulus? Will there be a limit to this response? Your answer : d.72 page 2 Passive Force 0. the second twitch generated more muscle force. Experiment Data: Voltage 8.83 1.2 grams.00 0.72 .64 5. the muscle tension generated by each successive stimulus also increased. 04/19/15 page 3 . 04/19/15 page 4 . Wave summation is achieved by You correctly answered: a. 04/19/15 page 5 . treppe. wave summation. 4. 1. the result is known as You correctly answered: c. In this experiment the isolated skeletal muscle was repetitively stimulated such that individual twitches overlapped with each other and resulted in a stronger muscle contraction than a standalone twitch.Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. This phenomenon is known as You correctly answered: c. Which of the following is not one of the ways that the body can increase the force produced by a skeletal muscle? You correctly answered: d. 3. increasing the rate of stimulus delivery (frequency) to the muscle. application of higher voltages to the whole muscle 2. When a muscle receives a stimulus frequency that causes non-overlapping twitches to follow each other closely in time such that the peak tension of each twitch rises in a stepwise fashion up to a plateau value. de tal manera que los estímulos lleguen uno tras otro separados por un período de tiempo corto. Compare and contrast frequency-dependent wave summation with motor unit recruitment (previously observed by increasing the stimulus voltage). did you have to increase the stimulus voltage above 8.5 5. To achieve an active force of 5. How are they similar? How was each achieved in the experiment? Explain how each is achieved in vivo. What is the difference between stimulus intensity and stimulus frequency? Your answer: la intensidad de estimulo es la accion que se ejerce sobre el musculo (puede ser quimico o electrico) para hacer que este se contraiga por un periodo determinado. Are these results called treppe or wave summation? Your answer: incrementando la frtecuencia de estimulos.5 (voltaje maximo) si dio oportunidad para que el musculo se reñlaje y siga con el efecto.2 g. por ejemplo al aumentar el voltaje a 10.Cuando un músculo esquelético es estimulado repetidaente. 2.2 g? How well did the results compare with your prediction? Your answer: sí. Este fenómeno se conoce como sumación. Your answer: la frecuencia depende de la la sumacion de impulsos que se pueda dar. In this experiment you observed the effect of stimulating the isolated skeletal muscle multiple times in a short period with complete relaxation between the stimuli. se logro aumentar la fuerza del musculo. How did the frequency of stimulation affect the amount of force generated by the isolated skeletal muscle when the frequency of stimulation was increased such that the muscle twitches did not fully relax between subsequent stimuli? Are these results called treppe or wave summation? How well did the results compare with your prediction? Your answer: al incrementar la frecuencia de estimulos sedio lo que conocemos como "efecto escalera"es decir . estos generaran una fuerza segun sea la frecuanecia. Describe the force of contraction with each subsequent stimulus. en cambio con un voltaje de 8. pero otra variable a tener en cuenta es la intensidad del voltaje para el efecto escalera. los resultados variaban porque la frecuencia de estimulos habia variado. elevando la frecuencia de las estimulaciones pero usando el voltaje maximo de 8. 3. 04/19/15 page 6 . 4. mientras que la frecuencia de estimulo es aplicar la misma accion( puede ser mayor o menor a la inicial) pero en un perido de tiempo establecido. how did you achieve an active force of 5.Review Sheet Results 1. cada contracción produce una fuerza ligeramente mayor que la anterior siempre y cuando el músculo se pueda relajar completamente entre estímulos relativamente próximos. las contracciones pueden superponerse entre sí y dar lugar a una contracción muscular más fuerte. por eso hablamos de frecuencia de estimulo. aun cuando en diferentes experimentos el voltaje era el mismo. este voltaje no dia oportunidad para que el musculo se relaje y continue eficientemente el efecto. es decir en periodos más cortos se obetenia una mayor fuerza generada por parte del musculo.5 volts? If not. Which of the following distinguishes a state of unfused tetanus from a state of complete (fused) tetanus? You correctly answered: d. maximal tetanic tension. 1.Exercise 2: Skeletal Muscle Physiology: Activity 4: Tetanus in Isolated Skeletal Muscle Lab Report Pre-lab Quiz Results You scored 100% by answering 3 out of 3 questions correctly. 04/19/15 page 1 . the muscle has reached its You correctly answered: a. When the stimulus frequency reaches a value beyond which no further increases in force are generated by the muscle. 3. the rate that stimulating voltage pulses are applied to an isolated whole skeletal muscle. 2. Muscle tension increases and decreases during a state of unfused tetanus. Stimulus frequency refers to You correctly answered: b. 88 5.00 0.12 5.95 5.95 5.5 8.00 0.5 Length 75 75 75 75 75 75 75 75 Stimuli/sec 50 130 140 142 144 146 148 150 04/19/15 Active Force 5. unfused tetanus develops How does the trace at 130 stimuli/sec compare with the trace at 50 stimuli/sec? You correctly answered: b.94 5. the muscle tension generated by each successive stimulus will increase.5 8. There will be a limit to this increase.12 5.88 5.00 0.5 8. Experiment Data: Voltage 8. Fused tetanus develops at this greater stimulus frequency.95 5.5 8.94 5. Maximal tetanic tension develops with these very high stimulation frequencies.00 0.95 5.94 5. what will happen to the muscle tension and twitch appearance with each successive stimulus? Will there be a limit to this response? Your answer : b.00 Total Force 5.95 .00 0.5 8.5 8.00 0.91 5. Stop & Think Questions: What begins to happen at around 80 msec? You correctly answered: c.00 0. As the stimulus frequency increases.95 page 2 Passive Force 0.Experiment Results Predict Question: Predict Question: As the stimulus frequency increases further.91 5.94 5. How do the traces with 146–150 stimuli per second compare with the trace at 130 stimuli per second? You correctly answered: d.5 8. 04/19/15 page 3 . 04/19/15 page 4 . 04/19/15 page 5 . 04/19/15 page 6 . Muscle tension increases and decreases between different values for an unfused tetanus. When the stimulus frequency reaches a value beyond which no further increases in force are generated by the muscle. maximal tetanic tension. sustained muscle tension due to very frequent stimuli. the muscle has reached its You correctly answered: a. Which of the following distinguishes a state of unfused tetanus from a state of complete (fused) tetanus? You correctly answered: d. 2.Post-lab Quiz Results You scored 100% by answering 3 out of 3 questions correctly. The term tetanus refers to You correctly answered: b. 3. 1. 91 y 146 genro una fuerza de 5.95. a 140 fue de 5. decimos que el músculo ha alcanzado su máxima tensión tetánica. a 140 estímulos / seg. at 140 stimuli/sec. Cuando la frecuencia de estimulación alcanza un valor más allá del cual no aumenta la fuerza generada por el músculo. 2. Indicate what type of force was developed by the isolated skeletal muscle in this activity at the following stimulus frequencies: at 50 stimuli/sec. pero hasta un tope ya que se da el estado de tetanos completos. y por encima de 146 estímulos / seg a un estimulo de 50 la fuersa generada fue de 5. este estado es conocido como tétanos completos (tétanos fusionados). 3. las contracciones comenzarán a unirse de tal manera que los picos y valles de cada contracción no se distinguirán unos de otros. Beyond what stimulus frequency is there no further increase in the peak force? What is the muscle tension called at this frequency? Your answer: Cuando la frecuencia de estimulación alcanza un valor más allá del cual no aumenta la fuerza generada por el músculo. How well did the results compare with your prediction? Your answer: Si se aplican estímulos incluso a mayor frecuencia. podemos observar que conforme aumenta el estimulo por segundo aumenta la fuerza generada.12. decimos que el músculo ha alcanzado su máxima tensión tetánica.Review Sheet Results 1. and above 146 stimuli/sec. Your answer: indicar qué tipo de fuerza fue desarrollado por el músculo esquelético aislado en esta actividad en las siguientes frecuencias de estímulo : a 50 estímulos / seg. Describe how increasing the stimulus frequency affected the force developed by the isolated whole skeletal muscle in this activity. 04/19/15 page 7 . When the stimulus frequency reaches a value beyond which no further increase of skeletal muscle force can occur. maximal tetanic tension. fatigue. repetitive stimulation is called You correctly answered: c. 1. A decline in a muscle's ability to maintain a constant level of force. 2. complete (fused) tetanus. after prolonged. buildup of Ca2+ in the muscle fibers 04/19/15 page 1 . 3.Exercise 2: Skeletal Muscle Physiology: Activity 5: Fatigue in Isolated Skeletal Muscle Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. the muscle is in a state known as You correctly answered: d. When skeletal muscle twitches fuse so that the peaks and valleys of each twitch become indistinguishable from each other. Which of the following is not thought to be a contributing factor to the development of fatigue? You correctly answered: a. or tension. 4. the muscle has reached its You correctly answered: c. 5 8.86 5. More than one of these answers could be correct. Stop & Think Questions: Why does the stimulated muscle force begin to decrease over time despite the maintained stimuli? (Note that a decrease in maximal force indicates muscle fatigue is developing. what will happen to the length of time that the muscle is able to sustain maximal developed tension when the stimulator is turned on again? Your answer : b.86 5.40 .86 5. Intracellular concentrations of ADP and Pi declined during the rest period. Why did the length of the intervening rest period affect the length of time the skeletal muscle can maintain maximum tension once the stimulator is turned on again? You correctly answered: c.5 8. Experiment Data: Voltage Stimuli/sec Rest Period (sec) Active Force (g) 8.) You correctly answered: d. The length of the rest period will proportionately increase the length of time for sustained muscle tension.5 8.20 5.Experiment Results Predict Question: Predict Question: If the stimulator is briefly turned off for defined periods of time.86 04/19/15 page 2 Sustained Maximal Force (sec) 10 10 0.5 120 120 120 120 0 0 8 21 5. 04/19/15 page 3 . the number of active cross bridges begins to decline although the rate of stimulus delivery (frequency) remains constant. The term tetanus refers to You correctly answered: b. 1.Post-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. repetitive stimulation is called You correctly answered: c. or tension. 04/19/15 page 4 . If an intervening rest period is imposed on active skeletal muscle You correctly answered: c. A decline in a muscle's ability to maintain a constant level of force. 4. sustained muscle tension due to repetitive stimuli. During fatigue You correctly answered: c. force is created by the You correctly answered: c. 2. the development of fatigue will be delayed. 3. after prolonged. power stroke of the myosin heads. fatigue. 5. During cross bridge cycling in skeletal muscle. When a skeletal muscle fatigues. ADP y Pj en los músculos. List a few ways that humans could delay the onset of fatigue when they are vigorously using their skeletal muscles. -adecuarse a entrenamientos si el ejercicio es para periodos cortos o largos.Review Sheet Results 1. -Trabajando la respiración. what happens to the contractile force over time? Your answer: Una disminución en la capacidad del músculo para mantener una fuerza de contracción constante tras una estimulación repetida y prolongada. Your answer: -Dandole un periodo adecuado de descanso a los musculos. What are some proposed causes of skeletal muscle fatigue? Your answer: Una de las causas de la fatiga en los ejercicios de alta intensidad. the muscle will produce more force for a longer time period if the stimulator is briefly turned off than if the stimuli were allowed to continue without interruption. 3. es la acumulación de ácido láctico. 04/19/15 page 5 . para poder llevar oxigeno a la sangre. Explain why this might occur. el musculo al ser estimulado no logra mantener la energia que genera como en el primer periodo. Thus. Turning the stimulator off allows a small measure of muscle recovery. How well did the results compare with your prediction? Your answer: cuando el periodo de descanso se acorta. 4. 2. tetanic force 5. 04/19/15 page 1 . The force that results from muscles being stretched is You correctly answered: a. Active force You correctly answered: b. 2. Passive force in skeletal muscle is largely caused by You correctly answered: c. When you generate the isometric length-tension curve. 4. but it remains at a fixed length. During an isometric contraction You correctly answered: d. 3. 1.Exercise 2: Skeletal Muscle Physiology: Activity 6: The Skeletal Muscle Length-Tension Relationship Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. which of the following forces will not be indicated on your screen? You correctly answered: c. the protein titin. the skeletal muscle is generating force. passive force. is determined by the amount of myosin bound to actin. 5 8.55 1.82 1.00 0.00 0.5 8.21 0.73 0. Why does this occur? You correctly answered: d.75 1.5 8.5 8.00 0. Stop & Think Questions: Note the dip in total force at a muscle length of 90 mm.00 0.25 1.21 0.82 1.5 8.5 8.75 Total Force 1.73 0.5 8. active force has decreased in value and passive force has not yet increased to a significant value.5 8.00 0.46 1.5 Length 75 70 65 60 55 50 80 90 100 Active Force 1.11 1.75 1.02 0. Total force can increase or decrease depending upon the starting resting length.11 04/19/15 page 2 Passive Force 0.77 1.Experiment Results Predict Question: Predict Question: As the resting length of the muscle is changed. At this muscle length.75 1.55 1. what will happen to the amount of total force the muscle generates during the stimulated twitch? Your answer : c.11 1.21 0.00 0.86 . Experiment Data: Voltage 8. 04/19/15 page 3 . 04/19/15 page 4 . 04/19/15 page 5 . 04/19/15 page 6 . 04/19/15 page 7 . 04/19/15 page 8 . 4. the fiber is at its resting length. Maximal active tension will be produced in a skeletal muscle fiber when You correctly answered: a. 04/19/15 page 9 . will utilize ATP hydrolysis to drive the cross bridge cycle. In skeletal muscle.Post-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1. 2. active force stimulated through a range of muscle lengths You correctly answered: b. When a skeletal muscle is stimulated and generates force but remains at a fixed length You correctly answered: d. Which protein is mostly responsible for the development of passive force in a muscle? You correctly answered: d. Which if the following is not depicted in a typical skeletal muscle isometric length-tension curve? You correctly answered: a. the muscle is contracting isometrically. time 5. titin 3. explain why active force varies with changes in the muscle's resting length. If you were curling a 7-kg dumbbell. 5. 2. 4.86 por cada gramo. when would your bicep muscles be contracting isometrically? Your answer: en base a los experimentos la fuerza generada sera de 1.Review Sheet Results 1. recordemos que la fuerza total es la suma de la fuerza pasiva y la fuerza activa. a medida que aumenta la longitus del musculo la fuerza activa que genera va aumentando complementandose con la fuerza pasiva. osea se generara 13020 unidades de fuerza. Durante la contracción isométrica elmúsculo se mantiene con una longitud fija (isométrico significa “misma longitud”. What happens to the amount of total force the muscle generates during the stimulated twitch? How well did the results compare with your prediction? Your answer: a un mismo estimulo (voltaje). Based on the unique arrangement of myosin and actin in skeletal muscle sarcomeres. Your answer: Como podemos observar en los experimentos. el músculo se contrae isométricamente. 04/19/15 page 10 . What skeletal muscle lengths generated passive force? (Provide a range. 3. es en base a la longitud del musculo. la fuerza total que se da. What is the key variable in an isometric contraction of a skeletal muscle? Your answer: la clave para que se de una concentracion isometrica es que el músculo intente soportar una carga que es igual a la fuerza que él genera.) Your answer: longitudes mayor o igual a 80. the length of the muscle changes. force generated by the muscle is greater than the weight of the attached load. 04/19/15 page 1 . 5. when muscle tension exceeds the load. An isotonic contraction of a muscle is one in which You correctly answered: a. Muscle shortening velocity You correctly answered: a.Exercise 2: Skeletal Muscle Physiology: Activity 7: Isotonic Contractions and the Load-Velocity Relationship Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. cross bridges cycle and. 3. During an isotonic concentric contraction. the You correctly answered: b. the latent period increases with heavier loads. 2. 1. During the latent period for an isotonic concentric contraction You correctly answered: c. decreases with heavier loads. 4. During an isotonic concentric contraction You correctly answered: b. muscle shortening occurs. 5 8.00 page 2 Distance Lifted (mm) 4.0 . isometric Experiment Data: Voltage Length Weight 8. The latent period will increase.Experiment Results Predict Question: Predict Question: As the load on the muscle increases. the shortening velocity.0 0.0 2. Stop & Think Questions: What kind of contraction did you observe when you attached the 2.5 8.00 0.5 1.5 0.5 75 75 75 75 0.00 30. the shortening velocity will decrease.057 0. what will happen to the latent period.000 04/19/15 Twitch Duration (msec) 78.0 Velocity (mm/msec) 0.0 gram weight to the skeletal muscle and stimulated a contraction? You correctly answered: c.00 49. and the contraction duration will decrease. the distance will decrease. the distance that the weight moves.022 0.0 1.5 2.100 0. and the contraction duration? Your answer : b.5 8. 04/19/15 page 3 . 04/19/15 page 4 . An isotonic contraction of a muscle is one in which You correctly answered: a.5-g weight 3. the length of the muscle changes. 04/19/15 page 5 .Post-lab Quiz Results You scored 100% by answering 6 out of 6 questions correctly. Which of the weights induced the longest latent period of the muscle contraction? You correctly answered: c. Which weight did the muscle contraction move the greatest distance? You correctly answered: a. 0. 1. When lifting a heavy load You correctly answered: d.5-g weight 4. the muscle shortening velocity is decreased in comparison with lighter loads. Which of the weights allowed the longest duration of muscle contraction? You correctly answered: a.5-g weight 5. 0. Which of the weights allowed the fastest muscle shortening velocity? You correctly answered: a.5-g weight 2. 6. 0. 1. Explain why the latent period became longer as the load became heavier in the experiment. How well did the results compare with your prediction? Your answer: a velocidad se acorta porque aumenta el peso que es levantado. Simultaneously. Your answer: las musculos que levantaran 10 repeticiones de 10kg comparadas con las de 5 kg. tendran una menor velocidad y una mayor concentracion isotonica. the muscle is maximally stimulated by 8. 3.5-g weight is attached to the end of the isolated whole skeletal muscle used in these experiments. pero si el peso es superior al de la capacidad de fuerza que puede ejercer el musculo. Describe how the shortening distance changed as the load became heavier in this experiment. Explain why the shortening velocity became slower as the load became heavier in this experiment. 2. este no podra ser levantado. when would your muscles be contracting isotonically? Your answer: si el bicep participa en el levantamiento de 7 kg. el músculo se acorta y esto hace que el peso se mueve. porque esta en una condicion isotonica. 4. Will the muscle generate force? Will the muscle change length? What is the name for this type of contraction? Your answer: El musculo genera más fuerza cuando un peso acorta su longitud isotonica. Describe what would happen in the following experiment: A 2. If you were using your bicep muscles to curl a 7-kg dumbbell. 5.Review Sheet Results 1. Explain why it would take you longer to perform 10 repetitions lifting a 10-kg weight than it would to perform the same number of repetitions with a 5-kg weight. How well did the results compare with your prediction? Your answer: El período de latencia aumenta a medida que aumenta el peso de la carga. 6.5 volts and the platform supporting the weight is removed. el objeto se levantara a una velocidad menor. 04/19/15 page 6 . How well did the results compare with your prediction? Your answer: a medida que el peso aumenta la distancia de acortamiento disminuye . Cuando la fuerza generada por el músculo supera el peso de a carga.
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