The Function of the Endocrine System - Glands and hormones

The Function of the Endocrine System: Glands and Hormones in Psychology

The endocrine system is responsible for the production and transmission of information in the body via messenger substances called hormones. Hormones are produced in specialised organs called glands as well as in endocrine cells located in various organs throughout the body.

The endocrine system works together with the nervous system to secrete hormones.

Their main function is to control and regulate biological processes and rhythms as well as developmental processes. They can work locally or use the bloodstream to travel throughout the whole body to their effector organs.

Once released into the bloodstream, hormones keep on circulating in the body until broken down by the liver and kidneys.

Endocrine System Organs and Functions

The endocrine system transports specialised hormones to the different body parts of the blood system. The different hormones are produced by glands. The endocrine system is composed of several glands, such as the Pituitary gland, the Thyroid gland, the Pineal gland and the Gonads.

Fig. 2 - The endocrine system is comprised of different glands and hormones.

Among all components of the Endocrin system, there is an organ of special relevance, the hypothalamus.

• The hypothalamus can be considered the control centre of the endocrine system.

The hypothalamus controls the release of hormones from the pituitary gland, the master gland. In this way, the hypothalamus and the pituitary gland are connected.

Types of Glands

Glands are specialised organs that create hormones or other substances, such as tears, sweat, milk, seminal fluid or saliva. Glands can be split into two categories:

• Exocrine glands: Secrete substances into ducts, examples include tear ducts and salivary glands.

• Endocrine glands: Secrete substances into the bloodstream.

Hormones are produced in the endocrine glands in the human body. The hormones they produce have one or many effectors, meaning the organs that they affect. The endocrine glands include the:

• Thyroid gland.

• Thymus.

• Pituitary gland.

• Pineal gland.

• Pancreas.

• Testes or Ovaries, depending on your biological sex.

• Adrenal glands.

Some hormones’ only function is to stimulate the release of other glands. These are called indirect action hormones. The glands cued to produce hormones by indirect action hormones are called target glands. Other hormones affect organs directly; these are called direct action hormones or effector hormones.

List of Endocrine Glands and their Hormones

As we discussed above, there are different types of endocrine glands. Consider the following list of endocrine glands and their hormones:

• The thyroid gland contains thyroid hormones (thyroxine and triiodothyronine) which influence growth and metabolism.

• The pineal gland releases melatonin and is involved in sleep.

• The pancreas is in charge of the production and release of insulin, which influences blood sugar levels and stimulates the metabolism of glucose, protein and fat.

• The testicles release androgens such as testosterone, which is involved in the development of male sexual characteristics.

• The ovaries release estrogen, which supports reproductive development in females and female sexual characteristics.

• The adrenal glands secrete two types of hormones: epinephrine - which is involved in oxygen intake, blood flow and heart rates - and norepinephrine - which is involved in blood pressure, blood vessels, and glucose release.

The Pituitary Gland

One of the most important glands is located in the brain; the pituitary gland, also called the master gland.

Part of it, the posterior pituitary gland, is an extension of the part of the brain called the hypothalamus. It is not glandular.

The other part, the anterior pituitary gland, is glandular and connects to the posterior pituitary and contains cells that produce many hormones. These so-called releasing hormones in turn tell the target glands in the body to produce local or specialised hormones that affect another set of organs in the body.

Glands, Hormones and their Functions Chart

Here there is a table of the different glands, and the hormones they release, together with the hormones' functions.

Endocrine System Diseases

There are certain diseases associated with failures of the endocrine system. These failures can take place due to two reasons:

1. A change in the level of hormones secreted by a gland.
2. A change in the gland's receptors sensitivity leads to the gland not responding correctly to stimulation.

Hormone imbalance can influence several conditions, such as mood or fertility. Among the diseases associated with the endocrine system are diabetes, hypothyroidism and hypogonadism. Let's take a look at these diseases.

Diabetes

Diabetes is a metabolic condition in which glucose concentration in the blood is high. The disease is caused by issues with insulin, which is produced in the pancreas.

There are two ways in which diabetes can occur. One is that the pancreas does not produce the necessary amount of insulin, a genetic condition, and the second is that the insulin receptors across the body present insensitivity to the hormone and less insulin is produced, a result of lifestyle choices.

Hypothyroidism

Hypothyroidism is a condition in which the supply of thyroid hormones is low. It can be preset due to two reasons.

• On the one hand, the thyroid can be producing low levels of thyroid hormones.
• While on the other hand, it could be that the thyroid-stimulating hormone is failing to achieve its function.

The effect that hypothyroidism is manifested in symptoms of fatigue, tiredness, constipation or muscle weakness

Hypogonadism

Hypogonadism refers to a spectrum disorder characterised by insufficient sex hormones. Equally to the previous two disorders, hypogonadism can arise due to a low level of the production of the hormones, or due to an insensitivity of the organs to the hormone themselves. The effects that the disorder has, vary depending on the time at which hypogonadism is developed.