Natsu with Lisanna, watching over their Dragon Egg. One day, Natsu found an egg in the forest east of Magnolia. Thinking it to be a Dragon Egg, Natsu took it to the guild and asked Makarov to make it hatch, but Makarov and Erza told him that he was the only one that could make the egg hatch; through love and care.
1 As a Decompression Chamberâ This is a hyperbaric chamber used by surface-supplied divers (commercial divers mostly) to make their decompression stops.  As Recompression chamberâ A hyperbaric chamber is used to treat or prevent patients suffering from decompression sickness.
The heart pumps blood in a two-step process. The atria pump blood into the ventricles and then the ventricles pump blood out of the heart. Chambers of the heart fill with blood during a relaxation phase (diastole) and eject blood during a contraction phase (systole). Atrial systole precedes ventricular systole.