What is Endocrinology? : The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. The study of the endocrine system and its disorders is known as endocrinology.

• Glands located throughout the body;
• Hormones that are made by the glands and released into the bloodstream or the fluid surrounding cells; and
• Receptors in various organs and tissues that recognize and respond to the hormones.

What is the Endocrine System? Endocrine disorders are diseases related to the endocrine glands of the body. The endocrine system produces hormones, which are chemical signals sent out, or secreted, through the bloodstream. Hormones help the body regulate processes, such as appetite, breathing, growth, fluid balance, feminization and virilization, and weight control.

The endocrine system consists of several glands, including the pituitary gland and hypothalamus in the brain, adrenal glands in the kidneys, and thyroid in the neck, as well as the pancreas, ovaries and testes. The stomach, liver and intestines also secrete hormones related to digestion. Most common endocrine disorders are related to improper functioning of the pancreas and the pituitary, thyroid and adrenal glands.

Common endocrine disorders include diabetes mellitus, acromegaly (overproduction of growth hormone), Addison’s disease (decreased production of hormones by the adrenal glands), Cushing’s syndrome (high cortisol levels for extended periods of time), Graves’ disease (type of hyperthyroidism resulting in excessive thyroid hormone production), Hashimoto’s thyroiditis (autoimmune disease resulting in hypothyroidism and low production of thyroid hormone), hyperthyroidism (overactive thyroid), hypothyroidism (underactive thyroid), and prolactinoma (overproduction of prolactin by the pituitary gland). These disorders often have widespread symptoms, affect multiple parts of the body, and can range in severity from mild to very severe. Treatments depend on the specific disorder but often focus on adjusting hormone balance using synthetic hormones.

 

Endocrine Glands

Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood.

The major glands of the endocrine system include the

• Pineal gland
• Pituitary gland
• Pancreas
• Ovaries
• Testes
• Thyroid gland
• Parathyroid gland
• Hypothalamus
• Adrenal glands

The hypothalamus and pituitary glands are neuroendocrine organs.

Where are Endocrine Glands Located in the Human 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.

Pituitary gland

No larger than the size of a pea, the pituitary is often referred to as the “master” gland because it releases hormones that regulate the function of endocrine glands such as the thyroid, adrenals and reproductive glands. It also produces hormones that stimulate the growth of bones and tissues, affect sexual development, encourage reabsorption of water by the kidneys and even trigger uterine contractions during and after labor.

Pineal body (pineal gland)

Located deep in the center of the brain, the pineal gland regulates several body functions through secretion of the hormone melatonin. Melatonin is released in a rhythmic cycle; it’s higher at night and helps regulate the sleep/wake cycle.

Pancreas

Located in the abdomen, the pancreas is both a digestive organ and an endocrine gland. The “islets of Langerhans” are the regions of the pancreas that contain its hormone-producing cells. The two primary endocrine functions of these cells are to keep the body supplied with fuel for energy and to help in food digestion by releasing digestive enzymes. The pancreas is the gland involved in diabetes.

Parathyroid glands

Each the size of a grain of rice, the body’s four parathyroid glands monitor the calcium level in our bodies. Parathyroid glands control the calcium levels in our blood, in our bones and throughout our body. Parathyroid glands regulate the calcium by producing a hormone called parathyroid hormone (PTH). The parathyroid glands also help the lining of the intestines become more efficient at absorbing calcium in the diet.

Thyroid gland

The butterfly-shaped thyroid takes iodine and converts it into two hormones (T3 and T4). These hormones move through the body and enter cells to regulate metabolism, including blood pressure, body temperature, heart rate and how the body reacts to other hormones.

The thyroid gland also produces calcitonin, which opposes the effects of PTH and acts to lower blood calcium levels. Calcitonin lowers blood calcium level by increasing the amount of calcium excreted in the urine and suppressing the activity of the osteoclasts, cells that degrade bone. Learn more about the thyroid and related conditions, such as hyperthyroidism.

Ovaries

The ovaries are the female sex glands. They have two main reproductive functions in the body: they produce oocytes (eggs) for fertilization and the reproductive hormones estrogen and progesterone.

Estrogen is involved in the development of female sexual features such as breast growth, the accumulation of body fat around the hips and thighs and the growth spurt that occurs during puberty. Both estrogen and progesterone are also involved in the regulation of the menstrual cycle and prepare the lining of the uterus for pregnancy.

Testes

The testes are the testicles or male sex glands. They have two functions: to produce sperm and to produce hormones — particularly testosterone — which regulate body changes associated with sexual development. These changes include enlargement of the penis, the growth spurt that occurs during puberty and the appearance of other male secondary sex characteristics (deepening of the voice, growth of facial and pubic hair, and the increase in muscle growth and strength).

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.

Diabetes mellitus (DM), commonly known as just diabetes, is a group of metabolic disorders characterized by a high blood sugar level over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased appetite. If left untreated, diabetes can cause many health complications. Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death. Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, damage to the nerves, damage to the eyes and cognitive impairment.

Diabetes is due to either the pancreas not producing enough insulin, or the cells of the body not responding properly to the insulin produced. There are three main types of diabetes mellitus:

1. Type 1 diabetes results from failure of the pancreas to produce enough insulin due to loss of beta cells. This form was previously referred to as "insulin-dependent diabetes mellitus" (IDDM) or "juvenile diabetes". The loss of beta cells is caused by an autoimmune response. The cause of this autoimmune response is unknown.
2. Type 2 diabetes begins with insulin resistance, a condition in which cells fail to respond to insulin properly. As the disease progresses, a lack of insulin may also develop. This form was previously referred to as "non insulin-dependent diabetes mellitus" (NIDDM) or "adult-onset diabetes". The most common cause is a combination of excessive body weight and insufficient exercise.
3. Gestational diabetes is the third main form, and occurs when pregnant women without a previous history of diabetes develop high blood sugar levels.

Thyroid disease is a general term for a medical condition that keeps your thyroid from making the right amount of hormones. Your thyroid typically makes hormones that keep your body functioning normally. When the thyroid makes too much thyroid hormone, your body uses energy too quickly. This is called hyperthyroidism. Using energy too quickly will do more than make you tired — it can make your heart beat faster, cause you to lose weight without trying and even make you feel nervous. On the flip-side of this, your thyroid can make too little thyroid hormone. This is called hypothyroidism. When you have too little thyroid hormone in your body, it can make you feel tired, you might gain weight and you may even be unable to tolerate cold temperatures.

These two main disorders can be caused by a variety of conditions. They can also be passed down through families (inherited).

Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly.Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities.

Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after menopause due to lower levels of estrogen. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, kidney disease, and surgical removal of the ovaries. Certain medications increase the rate of bone loss, including some antiseizure medications, chemotherapy, proton pump inhibitors, selective serotonin reuptake inhibitors, and glucocorticosteroids. Smoking, and too little exercise are also risk factors. Osteoporosis is defined as a bone density of 2.5 standard deviations below that of a young adult. This is typically measured by dual-energy X-ray absorptiometry.

Prevention of osteoporosis includes a proper diet during childhood and efforts to avoid medications that increase the rate of bone loss.

The glands in a person's body release hormones. Endocrinologists treat people who suffer from hormonal imbalances, typically from glands in the endocrine system or certain types of cancers. The overall goal of treatment is to restore the normal balance of hormones found in a patient's body.

• Diabetes (sugar in the blood)
• Thyroid disorders (thyroid swelling, thyroid cancer, hyperthyroidism, hypothyroidism)
• Irregular menstruation (oligomenorrhoea & Amenorrhoea)
• Obesity (overweight)
• Short stature (being too short)
• Tall stature (being too tall)
• Young Diabetes / hypertension (age less than 30years)
• Menopausal symptoms
• Osteoporosis (thin bones and repeated fractures)
• Excessive thirst or hunger
• Adrenal problems
• Calcium related problems
• Delayed puberty
• Early puberty
• Lack of sexual developmental
• Pituitary problems
• Problems with Sodium and Potassium metabolism
• Impairment in male sexual function
• Excessive hair growth in females
• Abnormal genitalia
• Genetic Disorders
• Recurrent kidney stones