What we’re talking about when we talk about hormones

Mood swings. Cravings. Exhaustion. Fluid retention. These are just a few of the symptoms around menstruation and pregnancy that can lead to the feeling or label of ‘hormonal.’ But hormones aren’t only associated with our reproductive system, they’re essential for almost every bodily function.

The human body is a beautiful, but complex, system so it makes sense that it would need an especially elegant communication system. That’s where hormones come in. Hormones are integral to our body’s production of energy, the maintenance of its internal environment, and reproduction because they are responsible for communication between organs and systems. Our hormones work closely with signals from the nervous system to regulate the body’s essential functions. Each hormone has a very specific message or set of messages, that, when needed, travels through the bloodstream from one organ to another and stimulates or inhibits actions that keep our bodies running properly. Some hormones are meant to circulate constantly in the body, though levels may change depending on the need, and some are only released in response to extreme circumstances.

endocrine system

The main sites of hormone production and action are in the glands of the endocrine system. These include the hypothalamus, pituitary, and pineal glands in the head, the thyroid and parathyroid glands in the neck, the thymus in the chest, and the pancreas, adrenal glands, ovaries, and testes in the abdomen. Many other organs, such as the heart, kidneys, and gastrointestinal tract, also secrete hormones important for bodily function, but the classic sites of hormone production hormones are controlled through the endocrine system.

Here’s a quick overview of the endocrine system glands, top to bottom, and what their hormones do:

  • Hypothalamus hormones maintain internal balance. They help regulate heart rate, blood pressure, body temperature, fluids and electrolytes, appetite, body weight, and sleep cycles. Because the hypothalamus gets information from almost all parts of the nervous system, these hormones are also responsible for releasing hormones in the pituitary gland to direct action throughout the endocrine system and to assist digestion in the stomach and intestines.

  • Pituitary gland hormones control the release of hormones in most of the other endocrine glands, regulate bone and muscle growth, and oxytocin release. The pituitary is often referred to as the “master gland.”

  • The pineal gland only produces one hormone, melatonin, to help maintain the body’s sleep cycle and help regulate some reproductive hormones.

  • Thyroid hormones regulate metabolism by breaking down food and converting it into usable energy. Every cell in our bodies depends on the thyroid to function properly.

  • Parathyroid gland hormones regulate the calcium level in the body.

  • Thymus hormones protect the body’s immune system from attacking itself, or autoimmunity, by ensuring the production of white blood cells called T-cells. This gland is only active until puberty and slowly shrinks, replaced by fat, throughout adulthood.

  • Pancreas hormones maintain the balance of blood glucose and salt in the body, assist digestion in the stomach, and regulate water and salt balance in the intestines.

  • Adrenal gland hormones regulate metabolism, immune responses, inflammatory reactions, help regulate blood pressure and the cardiovascular system and release small amounts of male and female sex hormones. Two important hormones controlled by the adrenal glands that work together to respond to stress are epinephrine, also called adrenaline and norepinephrine.

  • Ovary hormones, primarily in the female body, are estrogen and progesterone. They regulate the development of female reproductive organs and breasts, control the distribution of fat around reproductive organs during and after puberty, ensure fertility, regulate menstruation, and prepare the body for pregnancy and labor.

  • The testes, primarily in the male body, produce only testosterone to regulate the development of male reproductive organs, facial and body hair growth, muscle mass and bone density, libido, and sperm production.

When it’s working optimally, the endocrine system and its hormones help maintain the body’s health and wellbeing. When it isn’t, organs and systems of the body can falter, leading to health problems. This can come in the form of the body producing too much of any particular hormone (hyperfunction), too little (hypofunction), a bodily resistance to processing a hormone, or anatomical differences, such as having both ovaries and testes. Hormonal issues can be genetic or related to environmental factors like tumor growth.

So it’s true that the imbalance or normal fluctuations of sex hormones like estrogen can lead to that feeling we call ‘hormonal,’ but other hormones can have a hand in those feelings and other feelings can be considered hormonal. The hormones in the human body and their functions are vast; they are a part of almost all sites of wellness and disease. As always, if you’re concerned about your health in relation to hormones, or for any other reason, talk to your doctor or other health and wellness provider.

 

Sources:

Melmed, S., & Conn, P. M. (2005). Endocrinology: Basic and Clinical Principles. Totowa, NJ : Humana Press, 2005.

Neal, J. M. (2016). How the endocrine system works. Chichester, England : Wiley Blackwell, 2016.