ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The heart rate ofAnabas is about 40 beats/min when breathing water and air. Tachycardia occurs as the fish takes an air breath and the rate declines as the breath holding continues but water breathing stops. Bradycardia is observed during this later phase. By the time the next air breath is taken, the heart rate has dropped to 15–30 beats/min. The heart rate of a fish breathing normoxic water but prevented from surfacing is about 42/min. Bradycardia occurs in hypoxic water under similar conditions. Tachycardia is observed in active fish when breathing hypercarbic water and air. On exposure to air bradycardia is found in resting fish but tachycardia occurs during activity. In air,Anabas usually repeats a breath when the heart rate drops to 15–25 beats/min. Tachycardia occurs immediately following an air breath. Heart rate then returns over a period of 3–6 mins to the normal resting level of 30 beats/min. The gas composition of the suprabranchial chambers has been measured and its relationship with the occurrence of an air breath, tachycardia and bradycardia is described. The experimental results are discussed in relation to the anatomy of the blood supply to the respiratory organs. The possible role of respiratory gases and pH in the control of breathing and perfusion is also discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00697607
