The human pineal gland is a grayish red oval body with a length of (5-8) mm and a width of (3-5) mm, weighing (120-200) mg. Its development reaches its peak at the age of 7-8 years.The pineal gland is located atDiencephalonTop,Habenular commissureAndPosterior commissurebetween,QuadruplexIn the depression aboveThird ventricleThe top is also called supracerebral gland, one end of which is connected with the top of the third ventricle through the thin handle, and the third ventricle protrudes into the handle to formRecess of pineal gland。The pineal surface is covered byPia materContinuationconnective tissueThe capsule extends into the parenchyma with blood vessels, dividing the parenchyma into many irregular lobules, which are mainly composed ofPineal cell、Glial cellandnerve fiberEtc.
The pineal gland is not the heavenly eye and has nothing to do with perception.[1-2]
The pineal gland is rich in blood vessels, and its blood flow is second only tokidneyThe arterioles of the branches of the left and right posterior choroidal arteries penetrate the pineal capsule, run between the connective tissues, form a capillary network, and then converge through the veins to penetrate the capsule to form an azygos vein of the pineal gland, which eventually flows into the great cerebral vein.
The pineal nerves come from peripheral nerve fibers, including sympathetic, parasympathetic, commissural and peptide nerves.
Production mechanism
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The pineal gland originates from the neuroectoderm and is located at the top of the third ventricle.At 33-36 days of human embryo, the ependyma here thickens, which is the pineal primordium.Sometimes a small process, called the accessory pineal gland, may occur in front of it. Most of them disappear at the later stage of the embryo, but they can also remain to form adult cysts.At 2 months, the thickened pineal primordium protrudes outward, forming small sacs first, and then cells proliferate to form a solid organ. Only a small cavity is reserved at its base, which is called a recess.The pineal stalk is formed at the junction of pineal gland and diencephalon.At 5 months of the embryo, the cells differentiated into pineal cells and glial cells, and the cells gradually formed clusters and arranged in cords.At 6 months, pineal cells differentiated obviously, and by the 8th month, the pineal gland was close to the adult type.After birth, the pineal cells stopped proliferating, but the cells continued to grow, and the glial cells and stroma increased.In the late embryo and early infancy, pineal cells are composed of weakly chromaffin large cells and strongly chromaffin small cells (immature type).When the cells are mature, the nuclei appear concave or lobulated, with nucleoli, and the cytoplasm has chromaffin fine particles.The electron microscope showed that the pineal cells had secretory function in the late embryonic stage.Generally speaking, human pineal cells have no photosensitive function, and can not have several transitional types from photoreceptor cells to endocrine cells, such as primitive secretory fine photoreceptor cells with cilia, intermediate photoreceptor endocrine cells, and complete endocrine cells.
physiological function
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1. Secreting melatonin, inhibiting the secretion of pituitary follicle stimulating hormone and luteinizing hormone, and secreting a variety of peptide hormones with strong anti gonadotropin effect, thus effectively inhibiting the activity of gonads and the emergence of sexual characteristics.If the pineal gland is damaged, premature puberty and overdevelopment of reproductive organs will occur.
2. It secretes hypoglycemic factors, and its action time is longer than insulin, up to 24 hours.
3. The activity of pineal gland shows obvious periodicity. The secretion of melatonin in one day and night decreases with light, and increases with darkness. According to research, it may affect activities such as sleep and wakefulness.In addition, the activity of the pineal gland also presents monthly, quarterly and annual cycles. Scientists believe that the pineal gland may send "time signals" to the central nervous system in this way, thus affecting the body's "biological clock".
Related rumors
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Many places have set upQuantum wave velocityFor the whole brain training class dressed in high-tech clothing, some trainers claimed that they could not only "walk at a glance", but also develop the pineal gland - "when the pineal gland is opened, the heavenly eye will open, and you can see the contents of the book with your eyes closed".When students feel that they have not learned anything, the trainers usually say that "the students are too old, and if children are sent in early, they will have a bright future".[1]
In fact, the pineal gland has nothing to do with perception.Reading speed is subject to the transmission speed of the nervous system. Any speed must face the limit of human body, and the upper limit cannot be exceeded.It is a hoax to boast that you can improve your reading speed by exceeding the upper limit.[1]
Medical experts clearly said: "The reason why the 'pineal gland' is called the third eye of human beings is that the 'pineal gland' can secrete a hormone called melatonin, which makes people feel the changes of day and night." In other words, even if the 'pineal gland' is stimulated, people cannot be blindfolded.[2]
