The human pineal gland is located at the top of the third ventricle, so it is also called the nectary gland. One end of the pineal gland is connected with the top of the third ventricle through a thin stalk, and the third ventricle protrudes into the stalk to form a pineal recess.
5 ~ 8 mm long, 3 ~ 5~8mm wide and weighing 120 ~ 200 mg. It is a reddish oval body similar to beans.
Many people don't believe that the pineal gland is the third eye of human beings, which is incredible, but research has proved that this is an indisputable fact. Biologists have long discovered that there is an eye frame of a third eye on the skull of an extinct ancient animal.
Later, after some research, it was found that no matter turtles, fish, birds and animals or human ancestors had a third eye.
But with the evolution of biology, the third eye gradually moved from the skull to the brain and was hidden, becoming what we call the pineal gland.
The human naked eye also plays the role of focusing and condensing light like the lens of a camera, while the pineal gland plays the role of real photosensitive imaging like the CCD or negative of a camera.
The human pineal gland develops in childhood, but it begins to degenerate after 7 years old.
Many people think that this is the third eye of our creatures, the location of the soul and the center of enlightenment.
In history, the pineal gland used to be a gland with deep mystery.
The ancient Roman doctor and anatomist Galen first described the pineal gland.
He explained the origin of the name pineal gland (similar in size and shape to the fruit of lycopodium) and described its function from a medical point of view.
Later, Boshidoni, Metius and others put forward the theory of locating psychological ventricles, holding that various psychological functions are located in different ventricles, with the ventricles in front of the head responsible for imagination, the middle ventricle responsible for reason and the back ventricle responsible for memory. The pineal gland at the top of diencephalon has been related to the mind since then.
After the transformation of Augustine and others in the Middle Ages, the physiological pineal gland added some mysterious functions and became a place to adjust the human mind.
Later, some people used anatomical evidence to think that the pineal gland was the "third eye" of human degeneration, and even was artificially attached with religious significance.
Descartes chose the pineal gland as the place where the body and mind interact, not only because of the mystery of this gland.
He gave a logical and interesting demonstration process in On the Love of the Soul.
He believes that most human organs are paired and symmetrical, and other organs in the brain are also paired. For example, people have two eyes and two ears.
But why do people only have one stable and simple idea at the same time? What makes the two images seen by our eyes and the two sounds heard by our ears merge into one? Descartes thinks that there is only one possibility, and that is the only unpaired pineal gland in the brain, which brings these feelings together harmoniously.
From this, we can simply see Descartes' thought of mind-body resonance, so as to further understand his answer to "how the mind is perceived"