What are the Different Types of Hormones in Endocrine System?

Endocrine system is an integrated system of glands, each of which secretes different types of hormones that travel through the blood.

The hormones travel through the bloodstream, communicate within the human body and bind to special receptors on the target cells.

Hormones regulate the vital functions in the body: metabolism, growth and development, sleep, tissue functions, moods, and others.

There are different types of hormones in the endocrine system according to the gland.

What are the Different Types of Hormones in the Endocrine System?

Endocrine System

The endocrine system is an integrated system of glands, each of which secretes different types of hormones that travel through the blood.

The endocrine system differs from the exocrine glands, which in turn secrete their chemicals through channels.

The endocrine system resembles the nervous system as it transmits information, although it differs by the mechanism of action.

The endocrine system is slow but lengthy, as it lasts from a few hours to weeks. But the nervous system is fast but short-acting.

Hormones regulate the vital functions in the body: metabolism, growth and development, sleep, tissue functions, moods, and others.

Read here: Endocrine System and Mechanism of Hormone Action

The Function of the Endocrine System

The hormones produced by the endocrine glands in the body play a large and very important role in the body's functions, including the following:

• Metabolism, which occurs within the body, including metabolic processes associated with food.
• Initiation, development, and maintenance of processes related to sexual growth.
• Hormones regulate the speed of chemical reactions in various cells of the body.
• Stimulate some substances to move or move across cellular membranes in the body.
• Stimulate the growth and development of cells and tissues.
• Control of human thirst.
• Maintain body temperature constant.
• Control human temperament and cognitive abilities.

Read also: How Do Hormones Control Your Life?

Types of Hormones in Endocrine System

Hormones can be classified into three main types:

Amines: These are simple molecules.

Proteins and peptides: These are made from amino acid chains.

Steroids: These are derived from cholesterol.

Types of Hormones According to the Glands

According to the gland which secretes hormones in the body, different types of hormones in the body are as follows:

Hypothalamus Hormones

There is a group of hormones produced by the hypothalamus, which are primarily responsible for stimulating the secretion of pituitary gland hormones preventing the secretion. The most important hormones under the hypothalamus are:

• Corticotropin-releasing hormone
• Gonadotropin-releasing hormone
• Growth hormone-releasing hormone
• Thyrotropin-releasing hormone

Hormones of the Pituitary Gland

The pituitary gland is located at the bottom of the brain and does not exceed the size of the pea. The hormones secreted by this gland include:

• The growth hormone that stimulates bone and tissue growth.
• Thyroid-stimulating hormone, which stimulates the thyroid gland to secrete hormones.
• Adrenocorticotropic hormone, which stimulates the adrenal cortex to secrete steroids.
• Luteinizing hormone and Follicle-stimulating hormone, which controls sexual functions in the body, including the secretion of progesterone hormones; Estrogen in women and testosterone in men.
• Prolactin, which stimulates the secretion of milk in women.
• Antidiuretic hormone, which controls the loss of water from the body through the kidneys.
• Oxytocin stimulates the contraction of the uterine smooth muscle during childbirth and enhances milk secretion.

Hormones of the Adrenal Gland

In the human body, there are two adrenal glands, one on the right kidney and the other on the left kidney.

In fact, each consists of two main parts: the first is the adrenal cortex; the second is the adrenal medulla.  

Each part is responsible for the secretion of a group of hormones that can be described as follows:

Hormones of the adrenal cortex: They are characterized by two main types of corticosteroids: Glucocorticoids and Mineralocorticoids. The following is their statement:

Glucocorticoids:  namely hydrocortisone, and corticosterone.

Hydrocortisone regulates the conversion of carbohydrates, fats, and proteins into energy, as well as its role in controlling blood pressure and cardiovascular functions.

As for corticosterone, it is combined with hydrocortisone and controls the response of the immune system and inflammatory reactions in the body.

Mineralocorticoids: The most important of which is the aldosterone which controls the level of water and salts in the body, and thus regulates blood pressure.

Hormones of adrenal medulla: Although the importance of hormones secreted by the adrenal medulla is less important than that of the adrenal cortex, it has an important role in responding to emotional conditions and tension in various forms. These hormones include:

Adrenaline (also known as epinephrine), responds to stress by increasing strokes and pumping blood to the brain and bones, as well as raise blood sugar levels.

Norepinephrine works alongside adrenaline in stressful conditions, in addition to narrowing blood vessels in such cases, causing an increase in blood pressure.

Read more: Hormone Interactions with Target Cells

Hormones of the Thyroid Gland

The thyroid gland secretes two primary hormones, Triiodothyronine (20% of the total secretion of hormones) and Thyroxine-T4 (80% of secretion). It should be noted that triiodothyronine is the most powerful hormone.

Hormones of the Parathyroid Gland

 Parathyroid gland secrets a hormone is known as parathyroid hormone and works primarily on bone cells by stimulating calcium into the bloodstream.

Hormones of the Pineal Gland

The pineal gland is located in the center of the brain, it produces the hormone melatonin. The primary function of this hormone is to regulate the Circadian Rhythm, which is what happens during the twenty-four hours of the day, including waking up and sleeping. 

The hormone melatonin is also responsible for controlling the reproductive hormones and processes associated with the reproductive system. It should be noted that this hormone is very distinctive, as it is produced only by the presence of light.

Hormones of the Thymus Gland

Thymosin is the only hormone produced by the thymus gland. This hormone stimulates the development of T-cells that are part of the body's immune system. When they are fully mature, they migrate to the lymph nodes scattered in parts of the body. It also helps fight infections and diseases that humans may experience in their lives.

The Hormones of the Pancreatic Islets

The hormones produced by the pancreatic islets play an important role in regulating sugar levels and certain salts in the body. These hormones include:

1. Gastrin: This hormone stimulates the secretion of acids from the stomach to help digestion.

2.  Insulin: It helps control blood sugar levels by stimulating cells to absorb glucose.

3.  Glucagon: It acts in an opposite way to insulin, to maintain glucose sugar in the blood.

4.  Somatostatin: It is produced in cases where insulin and glucagon levels are too high to regulate sugar levels and salts in the body.

5.  Vasoactive intestinal peptide: It is controlled by the secretion of water and the absorption of water from the intestines.

Hormones of Reproductive glands

Reproductive glands are testes for males that secrete Sex hormones known as androgens, such as testosterone. The testicles in men work on the secretion of testosterone and work on the normal development of male genitalia, the masculine qualities are generally observed in terms of sound, muscle, and so on.

Likewise, the ovaries in females secrete two essential hormones, estrogen and progesterone. The ovaries are located on both sides of the uterus.

These hormones are responsible for the development of sexual characteristics in the female in adulthood, as well as responsible for the organization of menstruation and pregnancy and so on.

Sex hormones are also known as sex steroids, gonadocorticoids, and gonadal steroids. 

Read more: Polycystic Ovary Syndrome (PCOS) - Symptoms, Causes andTreatment