Cardiovascular responses during buccal and thoracic respiration in the lizard, Sauromalus obesus

Abstract

1. 1. The lizard Sauromalus obesus usually respires by thoracic movements but can ventilate and inflate its lungs by buccal movements. 2. 2. When the lungs were inflated intratracheal, intra-abdominal, carotid and sciatic vein pressures all rose above pre-inflation levels, but intrathoracic and vena cava pressures rose only moderately, or dropped below pre-inflation levels. 3. 3. Jugular pressure during the deglutitory pauses of inflation usually showed no increase. Heart rate usually increased. 4. 4. The data show little or no reason to suspect appreciable circulatory impairment resulting from the high intrapulmonary pressures of inflation.