The human body is a complex mechanism with millions or even billions of processes happening simultaneously to keep us alive and healthy. While all of our body functions in order to do so, it is the brain that regulates it all, brain controls each and every aspect of our existence from our physical movement to emotions with the help of hormones. It truly is astonishing how much we don’t realize the functionality of our brain, yet it occurs precisely and seamlessly.
What are Hormones?
As you might be familiar with the fact that our brain communicates with the rest of our body via chemical and electrical signals. Hormones can be considered as chemical messengers that are released directly into the bloodstream which then carries them to organs and tissues of the body for it to function accordingly. Hormones are responsible for our growth, development, metabolism, reproduction, emotions, and regulation of body temperature. As you can imagine these are essential for our survival, there are about eight endocrine glands (that are present without any ducts to release hormones directly into the bloodstream) in our body that releases about 200 hormones.
Types of Hormones in the Human Brain
While there are eight glands throughout our body that secret hormones, only three of them are present in the brain that releases crucial hormones that are responsible for our health and the regulations of other glands. While there are many types of hormones the two types that are released by the brain are either amino-acid derived or peptide hormones.
Molecular structure of Amino Acid.
Amino acid-derived hormones: These are relatively small molecules are comprised of amino acids tyrosine and tryptophan. Their chemical name will likely end with -ine, while the thyroid gland produces these largely it is also produced by the pineal gland.
Peptide hormones: While these are also a form of amino acids, they are derived from polypeptide chains which is a form of an amino acid chain. These include both short and large hormones released by the pituitary gland.
Hormones released by the Brain
As mentioned previously three main glands secrete hormones in the brain and these are Hypothalamus, pituitary gland, and pineal gland.
Hypothalamus hormones
While the hypothalamus in itself does not produce any hormones, it is considered as one of the glands when it comes to hormonal release, why? Because it controls two main functions, homeostasis, and hormones. While the former is responsible for balance and stability in a biological system, the latter controls the release of hormones. Though the pituitary gland is responsible for the secretion of hormones it wouldn’t be able to do it without the hypothalamus, as it synthesizes some hormones then returns them to the pituitary gland for their release in the bloodstream so, in a way, we can say that it releases hormones.
Location of Hypothalamus in the brain.
Pituitary Gland
Also known as one of the master glands as it is responsible for releasing many vital hormones and it also regulates other hormone-regulating glands within the body. It consists of two lobes; Anterior pituitary and posterior pituitary. While most of the hormones are released and synthesized by the anterior pituitary, two hormones are secreted by the posterior pituitary and are synthesized by the hypothalamus.
Structure of Pituitary gland.
- Adrenocorticotrophic hormone (ACTH): This hormone targets the adrenal gland, specifically its cortex and regulates the production and release of cortisol. Cortisol is the body’s stress hormone and is triggered in stressful or fearful situations, and cortisol also switches off basic functions like digestion and growth during these times to ensure survival by making one highly alert.
- Thyroid-stimulating hormone (TSH): As the name may suggest, this targets the thyroid, while it releases many hormones it is most known for the release of thyroxine also known as T4. This regulates metabolism and growth in an individual.
- Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH): Both are responsible for reproductive functions, the former targets the ovaries and commands them to release estrogen and progesterone. The latter controls the menstrual cycle and also triggers the release of eggs. While in men it targets testicles to release testosterone and sperm.
- Prolactin (PRL): While this hormone is present in both males and females, its impacts can only be seen in females. It targets and stimulates the breasts to produce milk, it is secreted in large amounts during pregnancy and breastfeeding.
- Growth hormone (GH): This is one of the essential hormones in the early stages of life as it targets basically the entire body and is responsible for growth and development along with repair of the body.
- Melanocyte-stimulating hormone (MSH): This hormone is one of the least studied and is not fully known. But it is linked with providing protection against UV rays and control of appetite.
- Anti-diuretic hormone (ADH): This solely focuses on the kidneys and controls the fluids and mineral levels within the body. As kidneys affect the water retention in the body and it also helps in blood pressure as well.
- Oxytocin: This hormone works around the uterus mainly but also has some effects on the breasts as well. It induces labor, strengthens the uterine contractions, or controlling bleeding after childbirth, and also subsequently triggers the release of milk of breast milk.
Pineal Gland
The pineal gland releases only one hormone, however, it is an essential one. It is a small cone-shaped structure that is located in the middle of two cerebral hemispheres and is about 6mm in size.
Locating of the pineal gland in the brain.
- Melatonin: Melatonin is released by the pineal gland in response to darkness and it helps with the circadian rhythms, the internal 24-hour clocks of our bodies. As you can imagine it is related to darkness, it triggers sleep as well and according to researches, it helps the body even in sleep.
These are the hormones that the brain produces. It is quite fascinating to think in how much detail our brain controls and regulates our physiology. Our bodies truly are a complex yet mesmerizing mechanism.
