Hormones make you feel happy and feel sad too. Hormones make you feel sleepy or feel hungry. Hormones are what make your glands sweat. Actually, they do much more than this. They regulate everything from metabolism, heart rate, mood, appetite, reproduction, growth and development, sleep cycles, to the menstrual cycle, and so on.
But what really are hormones? What are their jobs in the human body? What will happen if they are not in a balance? Let's find out!
In this lesson we are going to learn:
Hormones are chemical substances that act like messenger molecules in the body.
They are made by specialist cells, usually within endocrine glands (organs that make hormones). The major endocrine glands are the pituitary, pineal, thymus, thyroid, adrenal glands, and pancreas. In addition, men produce hormones in their testes and women produce them in their ovaries. The system of glands that make hormones is called endocrine system.
Once made within endocrine glands, hormones are released into the bloodstream in order to send a message to another part of the body. That is why they are referred to as chemical messengers. From here you can see that their role is to provide an internal communication system between cells located in distant parts of the body. Hormones can be found in all multicellular organisms.
In the human body, hormones are used for two types of communication:
Without the endocrine glands, and the hormones they release, the cells wouldn't know when to do important things.
Hormones are very powerful, only a very small amount can cause big changes in cells or in the whole body. Too much or too little of a certain hormone can be harmful.
Hormones affect many physiological activities including:
There are three major types of hormones.
Hormones can be categorized into three distinct groups according to their chemical composition. Because of that, they will have different mechanisms of action. The three types of hormones are:
Protein hormones or peptide hormones are hormones whose molecules are peptides (peptides are short strings of amino acids, typically comprising 2–50 amino acids) or proteins (large, complex molecules that play many critical roles in the body) respectively. Peptide hormones are made up of chains of amino acids. Most of them are water-soluble and can travel freely in the blood. These hormones have an effect on the endocrine system of animals, including humans. Insulin and prolactin are examples of peptide hormones.
Steroid hormones are steroids (biologically active organic compounds with four rings arranged in a specific molecular configuration) that acts as hormones. Steroid hormones can be grouped into two classes: corticosteroids and sex steroids. Within those two classes are five types according to the receptors to which they bind: glucocorticoids and mineralocorticoids and androgens, estrogens, and progestogens. Steroid hormones are derived from cholesterol. These hormones require carriers proteins to travel in the blood. Cortisol, estrogen, progesterone, testosterone are examples of steroid hormones.
Amine hormones are derived from a single amino acid (amino acids are molecules that combine to form proteins), either tyrosine or tryptophan. This class of hormones is unique because they share their mechanism of action with both steroid as well as peptide hormones. Adrenalin and thyroxine are examples of amine hormones.
| Hormone | Role in the human body |
| Hormones of Thyroid |
The thyroid gland basically releases two hormones Triiodothyronine (T3) and Thyroxine (T4). They help in controlling the metabolism of our body. Further, these hormones regulate weight, determine energy levels, internal body temperature, skin, hair, etc. |
| Insulin | Insulin is an essential hormone produced by the pancreas. Its main role is to control glucose levels in our bodies. |
| Progesterone | Progesterone hormone is produced in the ovaries, the placenta when a woman gets pregnant, and the adrenal glands. It plays an important role in maintaining pregnancy, preparing the body for conception, pregnancy and regulating the monthly cycle. |
| Estrogen | It is a female sex hormone released by the ovaries. It is responsible for reproduction, menstruation, and menopause. |
| Prolactin | This hormone is released by the pituitary gland after childbirth for lactation, which enables females to breastfeed. |
| Testosterone | It is a male sex hormone. It is an anabolic steroid by nature that helps in building body muscles. In males plays an important role in the development of male reproductive tissues, testes, and prostate. |
| Serotonin | Serotonin is the key hormone that stabilizes our mood, feelings of well-being, and happiness. This hormone impacts your entire body. It enables brain cells and other nervous system cells to communicate with each other. |
| Adrenaline |
Adrenaline, also called epinephrine, is a hormone released by your adrenal glands and some neurons. Adrenaline is a stress hormone. Key actions of adrenaline include increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, enlarging the pupil in the eye, redistributing blood to the muscles, etc. |
| Cortisol | Cortisol is a steroid hormone that regulates a wide range of vital processes throughout the body, including metabolism and the immune response. It also has a very important role in helping the body respond to stress. |
| Growth Hormone |
It is also known as the somatotropin hormone. It is basically a protein hormone having 190 amino acids. It stimulates growth, cell reproduction cell regeneration, and boosting metabolism. |
| Dopamine | Also known as the “feel-good” hormone, dopamine is a hormone and neurotransmitter that's an important part of your brain's reward system. Dopamine is associated with pleasurable sensations, along with learning, memory, motor system function, and more. |
| Oxytocin | Oxytocin is a hormone produced by the hypothalamus and secreted by the pituitary gland, and it is responsible for the sensation of love. This important hormone plays a crucial role in the childbirth process and also helps with male reproduction. |
| Melatonin | Melatonin, released by the pineal gland is a hormone that controls your sleep patterns. Levels increase at night time, making you feel sleepy. |
| Ghrelin | Ghrelin is a hormone termed the 'hunger hormone' because it stimulates appetite, increases food intake, and promotes fat storage. It is produced and released mainly by the stomach with small amounts also released by the small intestine, pancreas, and brain. |
Hormonal imbalances occur when there is too much or too little of a hormone in the bloodstream. Because of their essential role in the body, even small hormonal imbalances can cause side effects throughout the body.
When something is out of balance with your hormones, it has an effect on the whole system.
For instance, we know that the main role of the hormone Insulin is to control glucose levels in our bodies. If there is too little insulin, the body can no longer move glucose from the blood into the cells, causing high blood glucose levels. If the body secretes too much insulin, that will cause hypoglycemia or abnormally low blood sugar levels. Also, we know that prolactin is the hormone that enables females to breastfeed. But, if there are abnormally high levels of this hormone, can cause the production of breast milk in men and in women who are not pregnant or breastfeeding. A decrease in the amount of prolactin secreted can lead to insufficient milk being produced after giving birth.
Bloating, fatigue, irritability, hair loss, palpitations, mood swings, problems with blood sugar, trouble concentrating, infertility, are just a few symptoms of different hormone imbalances.
