The hormonal system (called the endocrine system in medical terminology) has various glands that release different hormones.

Hormones are like the body’s communication system. They take messages from one part of the body (the gland) to tell another part of the body (the target cell) to do something important. The endocrine glands influence reproduction, metabolism, growth and many other functions.

Below is a list of the main glands (see diagram for their location), some of the hormones they produce and what effects they have on the body.

Hypothalamus: an area in the base of the brain that links the brain to the hormonal system.

• major hormones — anti-diuretic hormone (ADH), oxytocin, dopamine, corticotrophin releasing hormone, thyrotrophin releasing hormone (TRH), gonadotrophin releasing hormone (GnRH), growth hormone releasing hormone (GHRH) and somatostatin
• influences — they hypothalamus links the hormonal and nervous systems. Its hormones keep the body stable. They influence sleep rhythms, alertness, appetite, body weight, thirst, blood pressure, heart rate, sex drive, learning, memory, mood and how the body responds to being sick

Pituitary gland: a kidney bean-shaped gland in the base of the brain.

• major hormones — luteinising hormone (LH), follicle-stimulating hormone (FSH), prolactin, growth hormone, thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH)
• influences — the pituitary gland helps control other glands and makes hormones that control blood pressure, blood sugar levels, response to stress, menstruation, sperm production, bone growth, muscle mass, contractions during childbirth, making breastmilk and bonding between mother and baby

Other glands

Pineal gland: a small gland near the centre of the brain.

• major hormones — melatonin
• influences — sleep cycle

Thyroid gland: a small gland in the front of the neck, wrapping around the windpipe.

• major hormones — tri-iodothyronine (T3), thyroxine (T4), calcitonin
• influences — metabolism, bone growth, energy levels, body temperature, how the cells use oxygen, heart rate, blood flow, calcium levels, vitamin metabolism, brain development in babies and children, and reproduction

Parathyroid glands: four small glands in the neck behind the thyroid gland.

• major hormones — parathyroid hormone (PTH)
• influences — regulating calcium levels in the blood

Adrenal glands: 2 glands that sit above the kidneys on each side of the body.

• major hormones — adrenaline, cortisol, aldosterone, DHEA, testosterone
• influences — stress response and blood pressure/salt and water control, blood sugar levels, energy, development of sex organs, heart rate, attention, inflammation, development of the fetus

Pancreas: a long gland behind the stomach, under the liver.

• major hormones — insulin, glucagon, somatostatin, vasoactive intestinal peptide (VIP)
• influences — blood sugar control

Ovaries (females only): 2 glands found on each side of the uterus in the pelvis.

• major hormones — oestrogen, progesterone, testosterone, anti-mullerian hormone (AMH), Inhibin A and Inhibin B
• influences — female characteristics, storing and releasing eggs

Testes (males only): 2 glands in the scrotum, behind the penis.

• major hormones — testosterone, anti-mullerian hormone (AMH), estradiol, inhibin B
• influences — male characteristics, sperm production

Find out more about the hormonal system.