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Amplitude distributions of the spider heartpulse in response to gravitational stimuliThe arachnid Nuctenea sclopetaria (Clerck) which possesses a neurogenic heart, measuring the heartbeat is under efferent control through a dorsal nerve arising from a brain center is discussed. It was shown that the heartrate of this spider is also modulated by an afferent input associated with small increments of gravity. A compressive force on the order of 40 micron is sufficient to elicit a threshold change in heart rate for a typical (100mg) spider. This obtains in a hyper-Gz field less than 1.001. The functional relationship between gravity and heartrate is logarithmic between the absolute threshold and at least 1.5 Gz. A model was proposed in which equilibrium and movement are maintained by changes in blood pressure. It is concluded that the arachnid equilibrium system is like a weight detector which employs a hydraulic compensatory mechanism.
Document ID
19840010773
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Finck, A.
(Temple Univ. Philadelphia, PA, United States)
Date Acquired
August 12, 2013
Publication Date
February 1, 1984
Publication Information
Publication: NASA. Washington NASA Space Biol. Program
Subject Category
Life Sciences (General)
Accession Number
84N18841
Funding Number(s)
CONTRACT_GRANT: NAGW-242
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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