Heart rates and amplitudes were measured for both intact
animals (in situ) and isolated hearts (in vitro) of the Dungeness crab,
Cancer magister, exposed to low levels in oxygen. Recordings were
also made of gill ventilation rate by measuring the frequency of
scaphognathite (gill bailer) beats.
Both the in vitro heart and the in situ heart beat showed a
marked decrease in amplitude and frequency under hypoxic stress.
Upon the return of oxygen to the environment, the recovery of the
hearts of the intact animals showed very short latent periods while the
recovery of the isolated hearts was very slow.
The response of the scaphognathites to hypoxia was biphasic.
Upon the initial decrease in oxygen concentration, they showed an
increase in beating frequency; with continued lowering of the oxygen
concentration, the rate fell off considerably.
In analysing the results it was concluded that such a decrease in
heart rate could be adaptive in that it could result in a lowered energy
demand at low oxygen concentrations. The rapid recovery of the in
situ hearts may indicate the presence of a receptor for oxygen. / Graduation date: 1970
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37246 |
| Date | 04 May 1970 |
| Creators | Stiffler, Daniel Francis |
| Contributors | Pritchard, Austin W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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