The endocrine system enables the body to maintain a state of balance or equilibrium. It does so by causing adjustments in the normal cellular functions, processes and rhythms so they operate in harmony. Music is the organized rhythmic harmonic sounds that creatures consciously produce. They perceive it, appreciate it and respond to it. On the strength of these truths, the endocrine system is the music of the body. And the orchestra plays on.
The endocrine system is a symphony of glands and the hormones that produce and release into the bloodstream. The orchestra is the sum total of the activities of the endocrine system and the cells, tissues and organs it effects. And the orchestra plays on.
The theater is the body – with its skeletal frame – and walls and roof of skin, muscle, sinews, and other connective tissue in between. The price of admission is birth. The performance is continuous and non-stop – for the orchestra plays on.
The players on instruments are the endocrine glands themselves. Their music is the hormones they secrete. The maestro of this biological orchestra is the hypothalamus of the brain. Its numerous receptors are the ears sensing the musical flow. Its many transmitted electrical and hormonal cues control the production and release of hormones by the glands much like the movements of the conductor direct the actions of the players on instruments. The hormones in turn evoke responses by the cells, tissues, and oranges much like music induces emotional responses in its listeners. And the orchestra plays on.
Endocrine glands also respond to conditions within the body much like players on instruments respond to conditions within the theater. It may be applause, lack of it, lighting, temperature, etc. Positive conditions heighten the performance and negative conditions might dampen it. Similar conditions in the body which disturb the body's equilibrium cause changes in the secretion of hormones affected by those conditions. Some examples are an abnormal blood sugar level, pregnancy, fluid deficiency, mineral imbalance, etc.
The audience of this symphony is the cells, tissues and organs of the body that respond to the hormones. The emotional responses of the audience are the changes in the bodily functions and processes in response to the hormones. The ears of the audience which govern the discrimination and appreciation of the overtones and harmonics of the symphony are the receptors on the cells and tissues. For it is the stimulation of those receptors by the hormones which evoke biological responses much like the music of an orchestra provokes emotional responses in its listeners. And the orchestra plays on.
The metaphor ends though with the realization that we do not carefully produce or orchestrate the music of our nonstop silent biological symphony. Neither do we consciously service it or maintain it. But yet, the orchestra plays on.