Healthy feet, healthy body: What hormones do

The main endocrine or hormone producing structures are as follows:

Pituitary gland

This is located at the base of the brain. It releases eight hormones, several of which affect other endocrine glands. For example, the thyroid stimulating hormone controls the output of the thyroid gland. The pituitary gland is often called the master gland, but it is actually regulated by chemical signals from another part of the brain – the hypothalamus , which also controls homeostasis via the nervous system.

Pineal gland

This is found deeper in the brain and secretes melatonin in response to darkness; this hormone regulates our daily rhythms.

Thyroid gland

This is found in front of the larynx and produces thyroxine, which sets the rate at which our cells convert nutrients and oxygen into energy – our metabolic rate. Excess thyroxine production, called hyperthyroidism, leads to mental and physical irritability, high body temperature and weight loss despite increased appetite.

The gland itself may become enlarged, known as goitre, and underactive thyroid – hypothyroidism – has the opposite symptoms.

Specialised beta cells in part of the pancreas, called the islets of Langerhans, release insulin, which controls the supply of glucose to the cells. Lack of insulin leads to diabetes. Type 1 insulin-dependent diabetes commonly begins around adolescence, while type 2 non-insulin dependent diabetes is associated with obesity and usually occurs in later life.

Adrenal glands

This is found above each kidney and consists of an outer cortex and inner medulla; the medulla produces the nervous system transmitters, adrenaline and noradrenalin.

The cortex is arranged in three layers, each producing a different group of steroids; cholesterol-based hormones. Mineral corticoids comes from the first layer, and regulate blood and urine mineral levels. The middle layer makes glucocorticoids, particularly hydrocortisone, that influence blood sugar levels, inflammation, the immune system and stress responses. The innermost layer makes small amounts of sex hormones.

Male and female sex glands

Also known as gonads, these develop in the abdomen during embryonic growth. In women, the ovaries descend into the pelvis and are attached to the uterus.

In men, the testes can’t produce sperm at internal body temperatures, so they travel out of the abdomen into the scrotum, usually before birth.

Lizél Britz, 072 243 7707