Muscle Contraction

Submitted by: Submitted by

Views: 3495

Words: 638

Pages: 3

Category: Philosophy and Psychology

Date Submitted: 03/12/2011 02:09 AM

Report This Essay

Exercise 1: The effects of nerve stimulation


To explore the motor and sensory effects of electrical stimuli on a student volunteer, using the nerves of the forearm.

Exercise2: Twitch response and recruitment


To measure the muscular twitch response to nerve stimulation, and to show recruitment in the twitch response as the stimulus strength increases.

Exercise3: Summation and tetanus


To demonstrate the effects of changing the interval between paired stimulus pulses, and to observe a short titanic contraction.

Results of Experiment2:

Table1: The effects of varying stimulus strength on twitch force.

Stimulus (mA) | Response (mV) |

0.0 | 0.00 |

0.5 | 0.00 |

1.0 | 0.00 |

1.5 | 0.00 |

2.0 | 0.00 |

2.5 | 0.00 |

3.0 | 0.00 |

3.5 | 0.00 |

4.0 | 0.00 |

4.5 | 2.90 |

5.0 | 5.33 |

5.5 | 6.18 |

6.0 | 17.09 |

6.5 | 31.64 |

7.0 | 38.56 |

7.5 | 52.03 |

8.0 | 55.12 |

8.5 | 53.99 |


1. Did you get a measurable twitch with a stimulus of 0mA?

No measurable twitch with a stimulus of 0mA.

2. What was the smallest current required to produce a contraction (the threshold current)?

Based on table1, the smallest current required to produce a contraction is 4.5mA.

3. What was the smallest current required to produce the maximum (largest) contraction?

From the table1, the smallest current required to produce the maximum contraction is 8.0mA

4. What happened to the number of fibers contracting as the current was raised from threshold to that required to produce a maximal contraction?

The numbers of fibers contracting have shown an increasing trend from the threshold down to the maximal contraction.

5. Why does varying the stimulus strength affect the twitch force?

This is because when varying the stimulus, the action potential is produced. Different degree of action potential caused by vary stimulus will result in different response of contraction. Hence, varying...

Related Essays

Skeletal Muscle: a Study Of Skeletal Muscle Contraction Mechanism In Fogs And The Various Factors Affecting It
response significantly. The contraction of skeletal muscle is controlled by the nervous system in the body. There is no muscle contraction below the threshold
a Study Of Muscle Contractions
individual muscle units contract as a unit, the entire muscle can contract on a graded basis due to their organization into motor units. Voluntary muscle contraction
Muscle Contractions
Muscle Contractions By: Evan Contractions, put simply, are the basic action of any muscle. A contraction is a change in a muscle by which it becomes thickened
Muscle Contraction
Reyes November 08, 2011 Dr. Dunaway Neuronal signaling in muscle contraction is triggered when an action potential reaches the neuromuscular junction