Exercise 1: The Effects Of Nerve Stimulation
Exercise 1: The effects of nerve stimulation
A. Describe briefly what you have done for this section (maximum 100 words).
Basically I am the volunteer. Two students handle the system while one student helps to spread the adequate electrode cream on the volunteer’s left wrist. The system is set to continuous, frequency is 1Hz, pulse duration at 200μs and pulse current at 10mA. The stimulator is switched off to disconnect the isolated stimulator terminals. The stimulus is then switched on and the bar stimulus electrode is placed on the volunteer’s wrist. The green light indicates the current is flowing. The twitches of thumb are noted at ulnar nerve. The stimulus bar is then fixed by using adhesive tape at spotted position. No data is recorded …show more content…
Threshold can be said that the level of needed stimulation to trigger the smallest measurable contraction resulting from the excitation and contraction of the first few muscle fibers [1]. The contraction can occur due to the depolarization of the plasma membrane so called sarcolemma. The depolarization can happen if the stimulus is enough to achieve the threshold. The stimulus cannot be lower than the threshold. Only then the action potential can be initiated. The action potential will be transmitted along the plasma membrane and down the T-tubules if the stimulus is above the threshold. The increase the stimulus, the more action potential. This will result the terminal cisternae of the sarcoplasmic reticulum releasing more calcium ions (Ca2+). The role of the calcium ions is to couple up the electrical excitation to muscle fiber contraction by binding to troponin. Troponin is a globular protein complex which is attached to the actin filament and tropomyosin. The tropomyosin will be changed its shape and pulled away from the myosin-binding sites on the actin filament when more troponins present. This permits myosin to form cross bridges with actin filaments of the sarcomere and produce the movement associated with the contraction. As cross bridges formed increase, the contraction becomes stronger. As a result, more respond is triggered. The strength of contraction is the sum of the force exerted by all the motor units that are excited. Therefore, varying the stimulus strength affect the twitch
A. Describe briefly what you have done for this section (maximum 100 words).
Basically I am the volunteer. Two students handle the system while one student helps to spread the adequate electrode cream on the volunteer’s left wrist. The system is set to continuous, frequency is 1Hz, pulse duration at 200μs and pulse current at 10mA. The stimulator is switched off to disconnect the isolated stimulator terminals. The stimulus is then switched on and the bar stimulus electrode is placed on the volunteer’s wrist. The green light indicates the current is flowing. The twitches of thumb are noted at ulnar nerve. The stimulus bar is then fixed by using adhesive tape at spotted position. No data is recorded …show more content…
Threshold can be said that the level of needed stimulation to trigger the smallest measurable contraction resulting from the excitation and contraction of the first few muscle fibers [1]. The contraction can occur due to the depolarization of the plasma membrane so called sarcolemma. The depolarization can happen if the stimulus is enough to achieve the threshold. The stimulus cannot be lower than the threshold. Only then the action potential can be initiated. The action potential will be transmitted along the plasma membrane and down the T-tubules if the stimulus is above the threshold. The increase the stimulus, the more action potential. This will result the terminal cisternae of the sarcoplasmic reticulum releasing more calcium ions (Ca2+). The role of the calcium ions is to couple up the electrical excitation to muscle fiber contraction by binding to troponin. Troponin is a globular protein complex which is attached to the actin filament and tropomyosin. The tropomyosin will be changed its shape and pulled away from the myosin-binding sites on the actin filament when more troponins present. This permits myosin to form cross bridges with actin filaments of the sarcomere and produce the movement associated with the contraction. As cross bridges formed increase, the contraction becomes stronger. As a result, more respond is triggered. The strength of contraction is the sum of the force exerted by all the motor units that are excited. Therefore, varying the stimulus strength affect the twitch