Also see user session. In telecommunication, a session is a series of interactions between two communication end points that occur during the span of a single connection.
The path of blood through the heart begins with the right atrium receiving blood, which has circulated through most of the body. This blood is relatively low in oxygen because most of it has already been delivered to different organs and tissues.
Blood is transported through the whole body by a continuum of blood vessels. Arteries are blood vessels that transport blood away from the heart, and veins transport the blood back to the heart. Capillaries carry blood to tissue cells and are the exchange sites of nutrients, gases, wastes, etc.