The arrows indicate the flow of air in of the human body through the respiratory system organs. In the above diagram, the air at first enters through the nose, then flows through the nasal cavity, pharynx, larynx, trachea, and then into the lungs through the Bronchi.
The endocrine system gets some help from organs such as the kidney, liver, heart and gonads, which have secondary endocrine functions. The kidney, for example, secretes hormones such as erythropoietin and renin.
Hormones and glands. Hormones are chemicals secreted by glands in the body. Different hormones affect different target organs. The bloodstream transports hormones from the glands to the target organs. Move the mouse over the different glands to see what they do. Hormones regulate the functions of many cells and organs.