. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. -•MH 44444 15 s Figure 4. Pressure in one branchiocardiac canal, gill EMG and ECG during hyperventilation (A) and swimming, as indicated by the large amplitude gill EMG's(B). Limulus occurs as alternating bouts of ventilation and apnea. Both hyperventilation and swimming are charac- terized by a large increase in rates of gill plate movements over that observed in shallow ventilation (Knudsen, 1973). The major difference between the two behaviors is that during swimming the legs also move in phase with the gills, while durin
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. -•MH 44444 15 s Figure 4. Pressure in one branchiocardiac canal, gill EMG and ECG during hyperventilation (A) and swimming, as indicated by the large amplitude gill EMG's(B). Limulus occurs as alternating bouts of ventilation and apnea. Both hyperventilation and swimming are charac- terized by a large increase in rates of gill plate movements over that observed in shallow ventilation (Knudsen, 1973). The major difference between the two behaviors is that during swimming the legs also move in phase with the gills, while during hyperventilation leg movements are independent of gill activity. During gill cleaning, the gill plates move across the midline and flick the inner lobe of a gill plate between the book gill lamellae of the opposite side. In all the aforementioned ventilatory ac- tivities, heart rate was always positively correlated with the rate of ventilation. These respiratory and locomotor behaviors of Limulus have also been reported in earlier papers (Watson and Wyse, 1978; Watson, 1980a, b). Pressures in the branchiocardiac canals during rest, ventilation, hyperventilation, and swimming The branchiocardiac canals (BCCs), as the term im- plies, carry blood from the gills to the pericardia! cavity and heart. Five pairs of canals correspond to the five gill appendages (Fig. 1). Blood from the venous circuit passes through an extensive gill network (Lockhead, 1950; Jo- hansen and Petersen, 1975) before returning to the heart. We measured pressures in one canal, while simulta- neously recording the electrical activity of that gill's closer muscle, during rest ( no ventilatory activity oc- curring), ventilation, hyperventilation, and swimming. During rest, no pressure pulses occur in the canal, al- though the pressure may be greater than zero (Fig. 2A). As the amplitude of ventilation increases, pressure in the canal rises substantially (3-20 cm H2O), as does the am- plitude and frequen
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
