The experiments conducted in the closed thorax show several examples of control mechanisms of the cardiac and circulatory functions. Accompanied by consistent monitoring of the ECG, pulse frequency and blood pressure, the following interventions are performed: 1. Simultaneous ligature of the carotids, 2. Separate electrostimulation of the vagus nerves, 3. Intravenous injection of acetylcholine (neurotransmitter), adrenaline (hormone) and Verapamil (medicament, calcium antagonist).