CIRCULATORY- ENDOCRINE 

- Hormones travel through the circulatory system.

- Organs that secrete hormones usually have big blood streams around, so that they could secrete those hormones on the blood and then the blood transports them to their target. The heart is myogenic (auto regulated), but sometimes hormones can affect it, like adrenalin.

- When you suffer from the thyroid (located on the upper part of the trachea. Image), you might be either tall or small because of growth hormones do not get to their target or get there in large amounts. This is only one example of the thyroid problem. As this gland is one the biggest in the endocrine system, it affects many other things.