home *** CD-ROM | disk | FTP | other *** search
/ Eyewitness: Encyclopedia of Science / Mac_DorlingKindersley_EyewitnessEncyclopediaOfScience.iso / mac / LISC / RENV / RENV000X.DIB (.png) < prev    next >
Bitmap Image  |  1995-06-29  |  52.8 KB  |  336x363  |  8-bit (33 colors)  |  [TEXT/LMAN]
   ocr: REFLEX ACTIONS RGANISMS need to respond instantly to certain situations without . having to think. This quick, automatic response to a stimulus 1S calleda reflex action. Ina a reflex action the stimulus always causes the same, short-lived response. For example, ifan animal steps on something sharp,n messages from the pain receptors in its foot travel to its spinal cord (the cluster of nervous tissue in a vertebrate's back) and go - out again quickly to the muscles in the leg. These muscles almostinstantly pull the foot away from the sharp object. Other reflex actions include the retreat of a w ...