. The Biological bulletin. Biology; Zoology; Marine biology. Blood pressure Dorsal aorta Figure 4. Blood pressure record from the dorsal aorta showing sustained gill contraction. Time marks, 2 seconds. aorta and connected with a Statham or Sanborn pressure transducer. Another incision in the branchial region exposed the systemic and portal hearts. Sometimes the gills themselves were dissected free in order to follow their movements closely. The pressures in the ventricle of the systemic heart and in the portal heart were recorded via cannulas (gauge 26) to the pressure transducers. Care was ta
. The Biological bulletin. Biology; Zoology; Marine biology. Blood pressure Dorsal aorta Figure 4. Blood pressure record from the dorsal aorta showing sustained gill contraction. Time marks, 2 seconds. aorta and connected with a Statham or Sanborn pressure transducer. Another incision in the branchial region exposed the systemic and portal hearts. Sometimes the gills themselves were dissected free in order to follow their movements closely. The pressures in the ventricle of the systemic heart and in the portal heart were recorded via cannulas (gauge 26) to the pressure transducers. Care was taken not to alter the horizontal position of the animals during the experiments and temperature changes in the lucite box were avoided. All recordings were made on a Sanborn 4-channel recorder. Results The systemic heart showed a frequency different from that of the portal heart. Both the systemic and portal hearts increased their frequency as a result of in- creased venous return brought about by digital manipulation of the great veins. The blood pressure recorded in the dorsal aorta showed a pattern like that demonstrated in Figure 2. The smaller oscillations are transmissions of the systemic heart beat through the gill capillaries. The larger paired pressure pulses were the result of active contractions of the gill musculature. These contractions most often came in pairs separated by variable times. The frequency of the gill contractions varied greatly, with average values of 8-10 per minute. Likewise, the absolute values of blood pressures in the dorsal aorta, as well as the rate of the systemic heart, showed great individual variations. The heart rates showed mm Hg i. Blood pressure Portal heart iinnHHiiimiHH Figure 5. Blood pressure record from the portal heart. Time marks, 1 Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectb, booksubjectzoology
