Biology 347 - General Physiology Lab - Stark and Kumar - Fall 2004
Quiz 2 - Postquiz on Electrophysiology and Neuro Interactive Physiology and Prequiz on Muscle Lab, 9/16/04

1. Last year, I added the force transducer to a lab that originally used only the hand dynanometer for the muscle lab. Why?

The force transducer can record small finger twitches based on stimulation of one of the muscles, if you could not achieve a forceful squeeze based on stimulation of the nerve.

2. The synch-out with delay from the stimulator could be used to put the voltage that was generated right in the same place on the oscilloscope face each sweep. How does the PowerLab recording system make this unnecessary?

On the power lab you can obtain the entire record then select and zoom anything you want.

3. If somebody is in contact with a live wire and is being electrocuted, why should you use the back of your hand and not your palm to try to knock the connection apart?

You might not be able to let go. Everybody should know this already! Here this question is presented in the context of a lab where electrical stimulation is supposed to elicit a hand squeeze.

4. What ion, critical to muscle contraction, binds troponin, pulling tropomyosin off of myosin's binding site on actin?


5. (Fill in the blank) An action potential in the spinal motor neuron goes to the _neuromuscular_

_junction_ of all the muscle fibers (cells) in the motor unit (all the striated muscle cells innervated by one spinal motor neuron).

6. What two electrical components are used in the circuits of high- and low-pass filters to give them the property of having a time constant?

resistor and capacitor

7. In the monosynaptic reflex as typified by the knee jerk, where is the stretch receptor?

the muscle spindle, with its receptor, is in the muscle

8. Suppose you are stimulating the nerve to the gastrocnemius muscle in the frog nerve muscle preparation. What would BoTox do to the response?

Since it blocks vesicle release, it would prevent the response

9. Why might a glass micropipette distort the shape of a fast action potential unless a negative capacity feedback electrometer is used?

because it is a low pass filter

10. How is it that we can see the heart's electrical activity by gripping two electrodes hooked to a polygraph?

Lots of cells depolarizing and repolarizing at once, Skin is the only substantial resistance between the heart and the electrode

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