Calculation of Pulse Velocity in the
Dorsal Blood Vessel of Lumbriculus variegatus
(Phylum Annelida; Class Oligochaeta; common name: blackworm)


Wait for the animation to load completely and play through once. To stop the animation, click on the "pause" button. To see the frame that precedes the paused frame, press the "previous" button. To see the frame that follows the paused frame, click on the "next" button. To resume the animation, click on the "play" button.

1) Wait for the full set of images to load.  This may take several seconds.
2) This animation shows the pulsation wave in the dorsal blood vessel of Lumbriculus variegatus. Four segments of the worm are shown, as viewed dorsally, at a location about mid-way along the body length.  The animation shows the progress of the pulsation wave during a five-second time interval. NOTE: Each frame advance represents 1/2 second (= 0.5 sec) of elapsed time.
3) Lay a clear transparency sheet over the animation. Use two small pieces of paper tape to secure corners of the transparency sheet to the monitor screen. Use a marking pen to make a series of dots on the sheet that track the frame-by-frame position (starting at 0 sec) of the pulse wave as it progresses from right to left. Make sure the correct elapsed time is recorded for each point of progress and make sure the distance scale is carefully recorded on the transparency sheet.
4) Use the distance and time scales to determine the velocity of the pulsation wave, expressed in units of mm/second.
5) If the pulsation wave moved at this same velocity over the entire length of a 5 centimeter-long worm, how long would it take the pulsation wave to travel the full length of the worm's body?

pulse frequency in mid-body segments]  [pulse frequency in posterior segments]  [blood vessel anatomy]

Click here to see non-interactive GIF animation 
Images were obtained by T. Sheffield.  Software for controlling interactive animations was developed by T. Drewes