Calculation
of Pulse Velocity in the
Dorsal Blood Vessel of Lumbriculus variegatus
(Phylum
Annelida; Class Oligochaeta; common name: blackworm)
CONTROLLING THE
ANIMATION:
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.
PROCEDURE:
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?
SEE RELATED LINKS: [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
