Pineal Gland: Anatomy, Functions, Disorders

It is a small, pinecone-shaped gland that is located in the middle area of the brain between the two hemispheres. This area is called the epithalamus. It was once called “the third eye”. It is where melatonin is secreted, and regulates the body’s internal rhythm (Circadian rhythm).

This gland is high in calcium. Calcium acts as a radiograph to locate the brain’s middle in X-ray images.

Anatomy of the Pineal Gland

The pineal gland measures approximately 0.3 inches in length and weighs 0.1 g. Its functions are controlled by the adrenergic nervous system that enters it.

It is formed of pinealocytes and supporting cells that are similar to the astrocytes found in the brain, and it is located in the hypothalamus.

A few lower vertebrates possess a well-developed, eye-like structure which acts as a light receiver.

Pineal Gland- Melatonin Secretes Hormones

The pineal gland synthesises serotonin and melatonin. They are therefore also known as the pineal gland hormone. Neurosteroids are also produced by the pineal gland.

Melatonin is produced as a result of the action of serotonin. Within the pineal gland, serotonin is acetylated and methylated, resulting in the production of melatonin. The amount of light that enters the eyes has an effect on the synthesis and secretion of melatonin.

Mel1A and Mel1B are the melatonin receptors that have been discovered in mammals. These receptors are cell surface G-protein coupled receptors.

Circadian rhythm is affected by melatonin.

The circadian rhythm, that is characterised by sleep-wake patterns, is a 24-hour biological cycle. Our circadian rhythms are controlled by the daylight and darkness. Exposure to light stops the secretion of melanin, which controls our circadian rhythms. Melatonin secretion is higher in the dark than it is during daylight. This affects our response to photoperiod.

Melatonin blocks the secretion gonadotropins by the anterior pituitary and affects reproduction. These hormones are essential for the development of testes and ovaries.

Functions of the Pineal Gland

Secretion of Melatonin

The hormone melatonin is secreted by this gland. It regulates the body’s circadian rhythm and certain reproductive hormones. This hormone is secreted depending on how much light an individual is exposed to. It is more active in dark environments. The absence of light can inhibit the production of melatonin, which regulates our circadian rhythms.

Cardiovascular Health

Melatonin secretion can have a positive effect on blood pressure and heart health. It can also be used to treat cardiovascular diseases.

Reproduction

Melatonin reduces the anterior pituitary’s release of reproductive hormones, which are important for the development and function of reproductive organs.

Disorders Of Pineal Gland

Below are a few conditions that can be caused by malfunctioning of the pineal nerve.

1. Depression.
2. Mood swings.
3. Stomach ulcers or Peptic.
4. Sleep disruption.
5. Hormonal imbalance can be caused by a dysfunction of the pineal gland.
6. The dysfunction of the pineal gland can cause sexual disorders.

Others include:

Low levels of melatonin can also lead to anxiety, low thyroid hormone production and menopause symptoms.

Hypersecretion of melatonin may lead to low blood pressure, improper functioning of the adrenal glands and thyroid glands .

A depressive disorder is one example of seasonal affective disorders in the pineal gland. This disorder is most common in winter when melatonin secretion rises due to low sunlight.

A tumour that develops in the pineal gland can affect many other parts of the body.

• Nausea
• Seizures
• Headache
• Memory disruption
• Perturbed vision and other senses

Researchers are currently researching the pineal gland to discover more about its functions. Its function remains a bit elusive.