Veins and arteries are the passageways blood uses to travel throughout the body.
heart
Esophogus
the passage way of blood is the vessel
the esophagus, of course
The tricuspid valve serves as a one way gate. It allows the blood to only travel in one direction from the right atrium to the right ventricle.
Hormones travel In the blood because they need to travel in the body.
Blood cells travel to and from the pump called the heart by way of the blood vessels called the arteries and veins.
It serves as a passage way for food travelling from the oral cavity to the esophagus and for air travelling from the nasal cavity to larynex
The trachea is the passage way for air to travel from the larynx to the lungs.
What is the passage way into the cell?
All the cells require oxygen, and so the way of them getting it is via the blood.
Messages to them usually travel by way of the blood.