Cardiopulmonary System

The cardiopulmonary system includes the heart and blood vessels, the lymphatic system, nose, nasopharynx, trachea, bronchi and lungs.  These interdependent systems are responsible for picking up and carrying oxygen to the cells of the body and transporting and discarding carbon dioxide.

Marine mammals are the deep diving athletes of the oceans with some species diving miles under the surface and staying submerged without breathing for up to two hours! How do they do this? Marine mammals have lots of physiological tricks and the cardiopulmonary system is central to their diving ability. Marine mammals as a group have increased blood volume, increased number of red blood cells, increased hemoglobin, and increased myoglobin in their muscles. All of these elements help them store extra oxygen in their bodies which can be used during a dive. Most marine mammals also undergo lung collapse during a dive which prevents most gas exchange from occurring at depth.

Detailed annotated images of the cardiopulmonary system in a California Sea Lion are shown below.  CLICK on an image to see an enlarged view.