The hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell.
In response to stress and changes in our biological clocks, such as day and night cycles and jet lag, hormones enter the blood and travel to the brain and other organs.
In the brain, hormones alter the production of gene products that participate in synaptic neurotransmission as well as affect the structure of brain cells.
As a result, the circuitry of the brain and its capacity for neurotransmission are changed over a course of hours to days. In this way, the brain adjusts its performance and control of behavior in response to a changing environment.
Endocrine glands are the organs responsible for producing and secreting hormones. Negative feedback in the endocrine system is the homeostatic mechanism that shuts off the stimulus that causes hormone release so that hormone secretion ends.
There are eight major endocrine glands, each performing a different function: the pituitary gland, the thyroid, the thymus gland, the adrenal gland, the ovaries (female) and testes (male), the pancreatic islets, and the pineal gland.
The endocrine system works with the nervous system and the immune system to help the body cope with different events and stresses.
To learn more, visit the following links:
https://www.betterhealth.vic.gov.au
http://www.brainfacts.org
http://www.pbs.org