Dorsal Blood Vessel Pulsations (mid-body)
Lumbriculus variegatus (blackworm)


This is a dorsal view showing two mid-body 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 wave.

2) Identify the dorsal blood vessel [see other images of blood vessels in Lumbriculus]

3) Describe what happens to the dorsal blood vessel, and the red blood that is within it, when a pulsation wave moves through a 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 posterior segments [see pulsation wave in posterior segments]

Related link: [Determine pulse velocity]

Images obtained by T. Sheffield