Endocrinology
Endocrinology is the study of hormones. Hormones are essential for our every-day survival. They control our temperature, sleep, mood, stress, growth and more.
An endocrinologist is a doctor that treats diseases related to problems with hormones. A hormone is a chemical messenger that travels from one cell to another. Hormones are released in one part of the body, travel in the blood stream and have an effect on other part of the body. This helps different parts of the human body to communicate with each other. Hormones are secreted by endocrine glands, such as the pituitary, thyroid or adrenal glands. Not all glands are classified as endocrine glands; for example, sweat glands or lymph glands are not endocrine glands.
Hormones are found in all organisms with more than one cell, and so they are found in plants and animals. They influence or control a wide range of physiological activities, such as growth, development, puberty, level of alertness, sugar regulation and appetite, bone growth, etc. You also find that problems with hormones and the way they work contribute to some of the major diseases of mankind; for example, diabetes, thyroid conditions, pituitary conditions, some sexual problems, some neurological problems, appetite and obesity, bone problems, cancer, etc.
There are whole sub-specialities devoted to specific areas where hormones work. For example:
Paediatric endocrinology, looking at hormones in children
Thyroid endocrinology, looking at how the thyroid affects metabolism
Endocrine-disrupting chemicals, where chemicals which mimic the effects of hormones are present in the environment
Comparative endocrinology, which looks at the way similar hormones work in different species (e.g. from insects, through to fish, birds, mammals, etc)
Sometimes there are specific societies devoted to the study of these subspecialities.
There are numerous textbooks which can give background information on endocrinology. For example, an online textbook can be found at
How the Endocrine System Works
The endocrine system’s glands and organs release hormones that regulate a number of vital functions of our body. These glands include the hypothalamus, pineal body, pituitary, thyroid, parathyroids, adrenals, pancreas, testes and ovaries.
The hormones in your body all have specific jobs to complete. There are up to 40 different hormones circulating in your blood at any time. Once released into the bloodstream, a hormone travels throughout the body until it reaches its specific destination(s) to perform its function. These destinations, called targets, can be located either on other endocrine glands or on other organs and tissues in the body.
When a hormone reaches its target, it tells that part of your body what work to do, when to do it and for how long. Hormones are often referred to as the “messengers” because they help different parts of the body communicate. Overall, they are involved in many different processes in the body, including:
- Blood sugar control
- Growth and development
- Metabolism (the process of getting and maintaining energy in the body)
- Regulation of heart rate and blood pressure
- Sexual development and function
- Reproduction
- Mood
What Happens When the Endocrine System Does Not Work?
Hormonal function is a balancing act. Too much or too little of one hormone can have an impact on the release of other hormones. If this hormonal imbalance occurs, some of your body’s systems will not work properly.
These imbalances can often be corrected by the body itself. Your body has built-in mechanisms to keep track of and respond to any changes in hormone levels to bring them back to normal and restore the balance.
Sometimes, however, this system goes wrong and there can be a problem that the body can’t fix itself. In this case, a primary care physician will refer you to an endocrinologist, who is an expert in treating frequently complex (and often chronic) conditions which can involve several different systems within the body.
The Anatomy of the Endocrine System
The endocrine system is made up of a collection of glands. Each gland has a specific function in the body, and all these glands work together to regulate vital functions of our body.
Adrenal glands
Located just above the kidneys, adrenal glands are responsible for the secretion of several hormones which maintain the body’s salt and water balance that in turn regulate blood pressure, help the body cope with and respond to stress, regulate body metabolism, and play a role in early development of the male sex organs in childhood and female body hair during puberty. The adrenal glands secrete 3 major hormones: mineralocorticoids (predominantly aldosterone), glucocorticoids (predominantly cortisol), and androgens (predominantly testosterone and dehydroepiandrosterone).
Hypothalamus
The hypothalamus is located just above the brain stem. It serves as the link between the endocrine system and the nervous system by communicating with the pituitary gland. It controls the pituitary gland by increasing or decreasing the release of hormones. It activates and controls involuntary functions such as body temperature, hunger and thirst.
