. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). ,156 MOVEMENT OF CILIA AND FLAGELLA (except fibrils 5 and 6). The resulting graph, Fig. 42b, follows a sine wave in which one complete cycle of flagellar bending occurs in each cycle of fibrillar contraction, so that the model would bend first to the right and then to the left before com- pletion of the cycle. By this means Gray was able to explain the symmetrical bending waves he found in some sea urchin sperm tails. An explanation of asymmetrical bending waves using these same assumptions is less easy unl
. The biology of cilia and flagella. Cilia and ciliary motion; Flagella (Microbiology). ,156 MOVEMENT OF CILIA AND FLAGELLA (except fibrils 5 and 6). The resulting graph, Fig. 42b, follows a sine wave in which one complete cycle of flagellar bending occurs in each cycle of fibrillar contraction, so that the model would bend first to the right and then to the left before com- pletion of the cycle. By this means Gray was able to explain the symmetrical bending waves he found in some sea urchin sperm tails. An explanation of asymmetrical bending waves using these same assumptions is less easy unless one also assumes that the ability to contract is greater on one side than the other. A small modification of Gray's theory suggested by Sleigh (1960) may provide a more satisfactory explanation of the various forms of ciliary and flagellar beating. z o w z u. TIME Fig. 43. Diagram of the course of contraction in a muscle fibre. Values from this curve were used to calculate fibrillar tensions in the construction of Fig. 44. The contraction cycle in a muscle fibre normally follows an asymmetrical course, as in Fig. 43. If we assume that the contraction in each ciliary fibril follows a curve like this rather than a sine curve, then a symmetrical bending cycle of the model would still be produced when each fibril is J cycle out of phase with its neighbours, as in Fig. 44a. If the phase difference between adjacent fibrils is greater than one-sixth, the bending cycle of the model will be asymmetrical or reduced in amplitude or both. If the phase difference is reduced to -^ cycle, the bending cycle is moderately asymmetrical (Fig. 44b), while if it is 2^4 cycle, the bending cycle is very asymmetrical (Fig. 44c).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Sleigh, Michael A. Oxford, New York, Pergamon Press
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