It is widely believed that blood is the life-sustaining medium. Blood has three primary functions in our bodies: transportation, protection, and regulation.
Blood transports good stuff (oxygen, nutrients, etc.) into to each cell of the body, and it transports not-so-good stuff (carbon dioxide, waste materials, etc.) out.
Blood also serves as the lead element of the "homeland security" system of the body. It carries around a host of "first responders" that initiate the protective response of the body when unhealthy invaders are at the door.
Blood also plays a regulatory role, serving as the bridge medium between and among all the integrated systems that make up our bodies (respiratory, digestive, muscular, etc.). It helps keep the interface among/between those systems functional and smoothly operating.
The best leaders I know are superb communicators. They effectively use varying types of communications methodologies as a sort of "blood" of the organization.
Those wise leaders know full well that the health of the organizational "blood" - communications - is the upstream determinate of the health of the organization.