Expt 4

|2006 - 2007 |EXPERIMENT 4 |Page 1 |

EXPERIMENT 4

Muscle

Introduction

In this experiment, you will explore how muscles work. You will electrically stimulate the nerves in the forearm to demonstrate recruitment, and will also examine the grip force.

Guillaume DuChenne (de Boulogne) (1806-1875) was the pioneer of human muscle stimulation.

[pic]

Figure 1. DuChenne's original equipment for stimulating human muscles.

Learning Objectives

By the end of today's laboratory you will be able to:

• Demonstrate the effects of electrical stimuli using the nerves of the forearm.

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

• Calibrate a hand dynamometer with respect to a volunteer's maximal grip strength.

|ENT 111/4 Human System | | |

|2006 - 2007 |EXPERIMENT 4 |Page 2 |

[pic]

Figure 2. The equipment set up

Equipment Setup

Caution!

Some exercises involve application of electrical shocks to muscle through electrodes placed on the skin.

People who have cardiac pacemakers or who suffer from neurological or cardiac disorders should not volunteer for such exercises.

If the volunteer feels major discomfort during the exercises, discontinue the exercise immediately and consult your instructor.

Procedure

1. Make sure the PowerLab is connected and turned on.

2. Connect the Finger Pulse Transducer to the BNC socket on Input 1 of the PowerLab.

3. Place the Finger Pulse Transducer diaphragm-side up on the top of...