Lumbriculus variegatus (blackworm)
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This is a dorsal view showing four posterior segments of a worm. Note the elapsed time (in seconds) and distance scale on the image.
1) Wait for the animation
images to load completely. Then, observe several cycles of the pulsation
2) Identify the dorsal blood vessel, as well as the lateral blood vessels that connect to it [see other images of blood vessels]
3) Describe what happens to the dorsal blood vessel and the lateral vessels in a segment when a pulsation wave moves through that segment.
4) In what direction do the pulsation waves move in relation to the worm's head and tail ends?
5) Refer to the time scale and note how much time elapses from beginning of one pulsation wave until the beginning of the next wave. Use this time to calculate the frequency of pulsation waves in units of waves/minute. Compare this frequency to the pulsation frequency in mid-body segments [See pulsation wave in mid-body segments]
Related link: [Determine pulse velocity]
Images obtained by T. Sheffield