Review of the glands
In the endocrine system, hormones are the prime currency. They communicate with, control, and coordinate bodily functions. Synthesized and secreted by endocrine glands, a hormone is comprised of specific molecules and serves as an able messenger.
The endocrine glands are ductless, which means, quite literally, that there are no ducts. Secretions are released directly into the bloodstream and travel within the body to target specific organs. This is in contrast to our digestive glands, which release digestive enzymes through ducts.
Each hormone's shape is specific, like a key to a lock. It can be recognized by the corresponding target cell. To maintain balance and homeostasis within the body, much hormonal regulation depends on feedback loops.
The major human endocrine glands include:
- This gland is located near the center of the brain, and is stimulated by nerves from the eyes. The pineal gland secretes melatonin at night when it is dark, more in winter when the nights are longer. This promotes sleep and affects reproductive functions by depressing the activity of the gonads. It also affects thyroid and adrenal cortex functions. The pineal is tied to circadian rhythms, annual cycles, and biological-clock functions. It is associated with the Crown chakra and the planet Saturn.
Pituitary gland and the hypothalamus
- The pituitary gland is called the "master gland," but is controlled by the hypothalamus. Together they coordinate many other endocrine functions. For example, they secrete hormones important to the female menstrual cycle, pregnancy, birth, and lactation. They influence growth, metabolism, and regeneration and serve to regulate hunger, thirst, sleep/wakefulness, and body temperature. They are associated with the Brow chakra and the planet Jupiter.
- Thyroid hormones regulate metabolism, body temperature, and weight. They contain iodine, which the thyroid needs in order to manufacture these hormones. The thyroid secretes the hormones necessary for calcium absorption. It is associated with the Throat chakra and the planet Mars.
- The thymus, associated with both the lymphatic and endocrine systems, is located in front of the heart and behind the sternum. It uses thymosin to stimulate T-cell formation and educates T-cells of the adaptive immune system. It is associated with the Heart chakra and the Sun.
- The pancreas is a glandular organ in the digestive and endocrine system that produces important hormones like glucagon and insulin to stimulate release and absorption of glucose. It secretes digestive enzymes that assist digestion and absorption of nutrients in the small intestine, breaking down carbohydrates, proteins, and lipids. The pancreas is associated with the Solar Plexus chakra and the planet Venus.
- The spleen is located in the left upper quadrant of the abdomen and acts primarily as a blood filter, like a large lymph node. It removes old red blood cells, holds a reserve of blood, and recycles iron. It is associated with the Hara or Chi chakra and the planet Mercury.
Gonads or sex organs
- In addition to producing gametes, the female ovaries and male testes also secrete hormones. The secretion of sex hormones by the gonads is controlled by pituitary gland hormones. Testosterone, estrogen, and progesterone are androgens secreted by these glands. They also control secondary sex characteristics. They are associated with the Sex chakra and the planet Moon.
- These glands sit on top of the kidneys and consist of two parts, the outer cortex and the inner medulla. The medulla secretes epinephrine, adrenaline, and other similar hormones in response to stressors such as fright, anger, caffeine, or low blood sugar. The cortex secretes cortisone for anti-inflammation, maintains salt-and-water balance, and regulates carbohydrate and protein metabolism. Adrenal glands are associated with the Root or Base chakra and the planet Earth.