REFERENCES 293 



10-2: Two platinum electrodes placed 3.0 cm apart on a nerve fiber detect the "wave 

 of negativity "of a transmitted impulse 0.37 milliseconds apart. Calculate the 

 speed of transmission in meters/sec, yards/sec, and miles per hour. Compare 

 this with the speed of sound in air (1090 feet/sec); of light through a vacuum 

 (186,000 miles/sec); of a signal along a telephone cable (1000 miles/ sec); of 

 the fastest thrown baseball (88 miles/hr); of the fastest sprinter (100 

 yds/ 10 sec). 



10-3: During the testing of a reflex at the sole of the foot, the signal must travel up 

 the leg to the spinal column and an order be transmitted back before the re- 

 sponse can occur. If the distance is 3 ft each way, how long should the interval 

 between stimulus and response be? 



10-4: Good rules-of-thumb to remember are: (a) the speed of shortening of a striated 

 muscle can reach a maximum value y max of about ten times its length per sec- 

 ond; and (b) it can exert a force which can reach a maximum F max of about 

 42 lb per sq in. of cross-sectional area of the muscle. 



Assuming the model of Figure 10-5, the force-velocity curve of Figure 10-10, 

 and the above data, calculate values of velocity with which three different 

 weight forces can be lifted, at v/v max equal to 0.1, 0.5, and 0.9. 



REFERENCES 



1. Keynes, R. D., "The Nerve Impulse and the Squid," Scientific American, 199, 



No. 6, p. 83(1958). 



2. Podolsky. R. D., "The Mechanism of Muscular Contraction," Amer. J. Medicine, 



30,708(1961). 



3. Huxley, H. E., "The Contraction of Muscle," Scientific Amer., 199, No. 5. p. 66 



(1958). 



4. Szent-Gyorgyi, A., "Mechanochemical Contraction in Muscle," in "Enzymes: 



Units of Biological Structure and Function," O. H. Gaebler, Ed., Academic 

 Press, New York, N. Y., 1956. 



5. Morales, M. F., et ai, "The Mechanism of Muscle Contraction," Physiol. Rev., 



35,475(1955). 



6. Hodgkin, A. L. and Keynes, R. D., "Active Transport of Cations in Giant Axons 



from Sepia and Loligo," J. Physiol., 128,28 (1955). 



7. Nachmansohn, D., "Chemical Factors Controlling Movements during Nerve Ac- 



tivity, from The Method of Isotopic Tracers Applied to the Study of Active Ion 

 Transport," Pergamon Press, New York, N. Y., 1959. 



8. Penfield, W., "The Interpretive Cortex," Science, 129, 1719 (1959). 



9. Walter, W. G., "The Living Brain," Penguin Books, Harmondsworth, England, 



1961. 



10. Shedlovsky, T., Ed., "Electrochemistry in Biology and Medicine,"John Wiley & 



Sons, Inc., New York, N, Y., 1955: review papers by B. K. Bagchi, H. H. 

 Jasper, K. S. Cole, and others. 



11. Hodgkin, A. L., "Ionic Movements and Electrical Activity in Giant Nerve 



Fibers," Proc. Roy. Soc, B., 148, 1 (1958); a fine review lecture. 



12. Szent-Gyorgyi, A., "Chemistry of Muscular Contraction," 3rd ed., Academic 



Press, Inc„ New York, N. Y., 1960. 



