Larry M

These are electromyograph (EMG) from a biceps muscle recordings taken during A and P I lab. Remember that electrodes are placed along the muscle and they sense the voltage change as the muscle cell membranes depolarizes with an action potential. The voltage difference (the y-axis or up and down trace) show the sum of all of the muscle cells whose membranes are depolarizing. The x-axis (or moving across the screen) is just time passing. The small voltage change was bending the elbow with no weight. The large voltage change was lifting a heavy book.

Larry M Frolich, Ph.D. ∞ Miami Dade College ∞ Wolfson Campus ∞ Natural Sciences ∞ Miami, FL 33132 ∞ Office 1504 ∞ (305) 237-7589 ∞ e-mail