Cranial nerves and spinal nerves Nerves that directly connect the brain and the brain stem with the eyes, ears, nose, and throat and with various parts of the head, neck, and trunk are called cranial nerves. There are 12 pairs of them (see Overview of the Cranial Nerves).

The portion of the brain that maintains the body’s internal balance (homeostasis). The hypothalamus is the link between the endocrine and nervous systems. The hypothalamus produces releasing and inhibiting hormones, which stop and start the production of other hormones throughout the body.

The endocrine system is linked to the nervous system by effects of the hypothalamus on the pituitary gland, as seen in the adjacent image. The pituitary gland is known as the ‘master gland’ because its secretions control the activity of other endocrine glands.

Hypothalamus: The hypothalamus (pronounced: hi-po-THAL-uh-mus) is in the lower central part of the brain. It links the endocrine system and nervous system. Nerve cells in the hypothalamus make chemicals that control the release of hormones secreted from the pituitary gland.

Amethyst

Amethyst jewelry has been found and dated as early as 2000 BC. Some historical accounts say that Saint Valentine had an amethyst ring carved with an image of Cupid. For those familiar with Old Testament history, amethyst was one of the twelve gemstones that represented the twelve tribes of Israel.

Amethyst is the purple variety of the quartz mineral species. It’s the gem that’s most commonly associated with the color purple, even though there are other purple gems such as sapphire and tanzanite. Its purple color can be cool and bluish, or a reddish purple that’s sometimes referred to as “raspberry.”

The word amethyst derives from the ancient Greek amethustos, which translates plainly to ‘not drunk’. This mystical belief in amethyst in keeping one sober extends back to 320 BC to the poet Asclepiades of Samos, likely inspired by the wine-like colours of this gem.

Often viewed as a stone of peace, some believe amethyst’s calming presence produces soothing dreams by bringing the dreamer more in tune with the Divine. This clarity and peacefulness also extends to the waking mind. Amethysts are said to help the mind flow freely in both mental and metaphysical dimensions.

The Greek word for amethyst translates to “not drunk,” and it is a good crystal for all types of addiction. The Greeks used to say that by keeping an amethyst in your mouth, you could drink all night and still stay sober.

Amethyst is quite common and is found on all continents, with the larger deposits currently being mined in South America, Africa and North America. The largest global producer is Brazil with an annual production of around two to three thousand tons followed by Zambia producing about a thousand tons per year.

: a dark natural glass formed by the cooling of molten lava.

Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. It is commonly found within the margins of rhyolitic lava flows known as obsidian flows….

What is obsidian used for? Obsidian has been used across history to make weapons, implements, tools, ornaments, and mirrors. Because of its conchoidal fracture (smooth curved surfaces and sharp edges), the sharpest stone artifacts were fashioned from obsidian.

Obsidian is an “extrusive” rock, which means it is made from magma that erupted out of a volcano. If it was an igneous rock that formed from magma underground and did not erupt, it would have been called an “intrusive” rock.

The peoples of ancient Mexico used polished obsidian mirrors, or tezcatl, as instruments of black magic. Obsidian mirrors are an apt metaphor for images of ancient Mexican sites and objects: they reflect the viewer as well as the object.