Endocrine System Structure & Function
The two main structures of the endocrine system are glands and hormones. Glands are organs that produce hormones. Hormones are chemical messengers that travel through the blood to allow for communication in the body.
What are the 3 main functions of the endocrine system?
The three main functions of the endocrine system are to:
- Produce hormones.
- Release hormones into the blood to control bodily functions, such as mood, appetite, sleep and more.
- Regulate the release of hormones so that they are in homeostasis with the body.
What is the Endocrine System?
The endocrine system is the collection of cells, tissues and organs in the body that control the production of hormones. Hormones are chemical messengers that control functions in the body and help maintain homeostasis. Some examples of functions controlled by hormones include:
The purpose of the endocrine system is to control the release of hormones to regulate these functions and help maintain homeostasis, or a balance in the body.
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The Endocrine System
The body is absolutely amazing! Think about everything that happens in the body on a day-to-day basis. Your digestive system breaks down food and converts it into energy. Your musculoskeletal system works with your nervous system to produce movement. Your immune system defends your body, and your urinary system gets rid of waste and maintains homeostasis in the body. Each of these systems carries out their functions and makes sure your body work like a factory.
The body, like all factories, has to know when to start and stop production of each of its products. When there’s a need for a product, then the factory manager sends a signal that starts production of that product. When enough of the product is made, then the factory manager sends a signal that stops production of the product.
That is similar to what happens in the body. This process is carried out by the endocrine system, which is the body system that communicates and controls functions in the body. This control is maintained through chemical messengers called hormones that are released by glands, or cells or organs that secrete.
Want an example of a hormone? Let’s discuss one that many people wish they could consciously control. Leptin is a hormone that indicates you are full and no longer hungry. This is often referred to as the satiety hormone. Being able to control the release of leptin would make weight loss much easier. We would all be able to release this hormone and no longer feel like we’re hungry. No more overeating!
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- 0:55 The Endocrine System
- 1:37 Control Glands
- 2:48 Glands Controlled by…
- 4:28 Glands Not Controlled…
- 6:08 Types of Hormones
- 6:50 Lesson Summary
Endocrine System Structure
What makes up the endocrine system, and specifically what organs make up the endocrine system? There are two main components of the endocrine system, glands and hormones. The first endocrine system structure are glands. Glands are organs that produce hormones and are located throughout the body. Glands produce hormones and release them in response to different conditions in the body. The hormones then travel through the blood stream and reach their effector organs and tissues where they can have an effect. Examples of organs in the endocrine system include:
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What is the Main Function of the Endocrine System?
The main function of the endocrine system is to maintain homeostasis in the body. Homeostasis is a stable set of internal conditions that are necessary for supporting life. The endocrine system receives input from the nervous system about changes in the body or the environment and then releases hormones to help balance changes and keep the body at homeostasis. The endocrine system organs and functions are essential for keeping us alive.
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Endocrine Glands
Glands are organs that release hormones. Glands work together in order to control our body functions and maintain homeostasis. There are two main control glands, which regulate hormone production from other glands. Both of these control glands are located in the brain, the hypothalamus and the pituitary gland. These two glands are important because they release hormones that regulate the function of other endocrine organs, and thus are called master glands or control glands. Each of the glands in the endocrine system is described in more detail in the sections below.
Hypothalamus
The hypothalamus is located in the base of the brain, near the optic chiasm. The hypothalamus is connected to the pituitary gland through both a special blood vessel network that directly transports hormones to the pituitary gland, and through a neural connection. This allows the hypothalamus to control the pituitary gland and through the pituitary, control functions such as water balance, sleep, temperature, blood pressure and more. In this way, the hypothalamus is like a production manager in the endocrine system.
Pituitary gland
The pituitary gland is also located in the brain. It is controlled by the hypothalamus and secretes hormones that control the function of many other endocrine organs in the body. The pituitary gland is divided into the anterior and posterior portions and each secrete different hormones. The anterior portion controls growth and cell division, breast milk production, the thyroid glands, adrenal glands, and reproduction. The posterior portion controls uterine contractions and blood pressure.
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Hormones
Hormones are the chemical messengers that are secreted by glands. There are many hormones in the body and they have various target organs and functions. The origin and primary function of some of the major hormones in the body are described in the table below.
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Lesson Summary
The endocrine system is a collection of cells, tissues and organs that release hormones. Hormones are chemical messengers that control homeostasis in the body by diffusing through the blood to their target tissues. Some examples of hormones include:
- Insulin – Regulates blood glucose levels
- Estrogen – Regulates production and release of eggs and secondary sex characteristics like breast development
- Melatonin – Regulates the sleep and wake cycle
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Control Glands
There are several glands located throughout the body, and all of them are important. However, there are two glands in the brain that are like the masterminds of the other organs. The hypothalamus is a lot like the operations manager in a factory that makes sure every aspect of the factory is functioning optimally. The hypothalamus is a small gland in the brain that assesses the body’s environment and releases hormones that control other glands. The hypothalamus essentially coordinates and dictates the activities of all other glands in order to keep the body functioning properly.
The other major gland in the brain is the pituitary gland. This is the gland that controls the rest of the endocrine system. This may start to seem like the body factory has two operations managers. The pituitary gland does control the rest of the endocrine system, but it does so under the direction of the hypothalamus. So the operations manager, or hypothalamus, tells the production manager, or pituitary gland, when production of the different hormones should start and stop. The pituitary gland is divided into the anterior and posterior pituitary glands.
Glands Controlled by the Pituitary Glands
Our first set of glands in the body are the ones controlled by the anterior pituitary gland. Let’s look at each of these now.
The thyroid gland is the gland located in the neck between the larynx and trachea. Hormones are secreted by the thyroid when the anterior pituitary gland, or production manager, sends the signal to start production. The thyroid hormones directly affect metabolism and indirectly affect blood calcium levels.
The adrenal glands are the triangle-shaped glands that sit on top of the kidneys. There are two sections of the adrenal glands: the adrenal cortex and adrenal medulla. Only the adrenal cortex responds to the anterior pituitary gland. The hormones released by the adrenal cortex control blood pressure, the immune system, and energy conversion. The hormones of the adrenal medulla are released in response to stress.
The last pair of glands that are under control of the pituitary gland are the gonads or sex glands, which are glands that secrete sex hormones. We’ll look at each of these separately, since they are different in males versus females.
Ladies first! The small, oval-shaped pair of female gonads are the ovaries, which secrete two different hormones that control the female reproductive cycle and the process of puberty.
The oval-shaped male gonads located in the scrotum are the testes. A hormone to control the development of male body characteristics is released by the testes when the production manager sends production signals to the testes.
Glands Not Controlled by the Pituitary Glands
Another gland that is located in the brain is the pineal gland, also sometimes called the third eye. It gets that nickname because it is activated based on signals from the optic nerve. So this gland isn’t really part of the factory that works together. The pineal gland is a gland shaped similar to a corn kernel and secretes several hormones. The pineal gland hormones affect secretion of hormones from the ovaries and a person’s sleep-wake cycle.
Our next gland is the parathyroid gland, which is the gland that surrounds the thyroid glands. The parathyroid gland is composed of four tiny glands that secrete PTH, which controls the blood calcium levels, allowing the muscular and nervous systems to function optimally. Parathyroid action is controlled by changes in calcium levels in the blood and does not change in response to another gland.
The pancreas is the flat gland attached to the small intestines behind the stomach that regulates blood glucose levels. Activation of the pancreas is controlled by detection of changes in blood glucose levels. Maintaining blood glucose levels is vitally important in order for the body to function as it should.
The final gland we are going to discuss is the thymus. The thymus is a two-lobed gland located in the upper chest between the lungs. Now that you are an adult, you don’t have any use for this gland, and in fact, it has diminished since you hit puberty. A group of hormones are released by the thymus that make the T-cells of the immune system develop. This gland is of the utmost importance in causing the immune system to develop.
Types of Hormones
Glands are one part of the endocrine system, but the other components of this system are the hormones. There are various types of hormones.
Steroid hormones are the cholesterol-based chemical messengers. Some steroid hormones make up sex hormones and others are classified as corticosteroids that are released by the adrenal cortex. There are also synthetic male sex hormones called anabolic steroids. Anabolic steroids have the same effect in the body as the male sex hormone.
The last type of hormone is the neurohormone. These are hormones that are released by the nervous system that are able to affect glands in the endocrine system.
Lesson Summary
You should have some insight into the endocrine system at this point. This is the body system that communicates and controls functions in the body. We learned that chemical messengers are hormones. Glands are groups of cells or an organ that secrete substances. We looked at leptin, the hormone that lets you know you are full, as an example of a hormone. This is also called the satiety hormone.
The two glands in the brain that control other glands are the hypothalamus and pituitary gland. The hypothalamus is the gland in the brain that controls the actions of almost all other glands. The pituitary gland is the gland below the hypothalamus that controls most other glands in the rest of the endocrine system. This is divided into the anterior and posterior pituitary glands.
We then covered the following glands that are controlled by the anterior pituitary gland:
- Thyroid gland – the gland in the neck between the larynx and trachea that controls metabolism
- Adrenal glands – the glands that sit on top of the kidneys that control blood pressure, the immune system, energy conversion, and stress
- Gonads or sex glands – glands that secrete sex hormones
- Ovaries – female gonads that control the female reproductive cycle and puberty
- Testes – male gonads that cause development from male body characteristics
The other glands covered in this lesson include:
- Pineal gland – gland in the brain that secretes several hormones in response to the optic nerve
- Parathyroid gland – gland surrounding the thyroid gland that controls blood calcium
- Pancreas – gland attached to the small intestines that regulates blood glucose levels
- Thymus – gland in the upper chest between the lungs that causes development of T-cells
The last thing that we discussed that you should now know are the types of hormones. Steroid hormones are cholesterol-based chemical messengers. Anabolic steroids are synthetic male sex hormones, and neurohormones are hormones released by the nervous system.
Lesson at a Glance
The endocrine system is responsible for communicating and controlling functions throughout the body. With the help of glands, hormones are released that sends messages to start, stop, or continue a particular function.
Learning Outcomes
After reviewing this lesson, you should be able to:
- Identify the function of the endocrine system
- Name glands controlled by the hypothalamus and by the pituitary gland
- Describe the function of other glands in the body
- Explain the function of hormones
Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.
The Endocrine System
The body is absolutely amazing! Think about everything that happens in the body on a day-to-day basis. Your digestive system breaks down food and converts it into energy. Your musculoskeletal system works with your nervous system to produce movement. Your immune system defends your body, and your urinary system gets rid of waste and maintains homeostasis in the body. Each of these systems carries out their functions and makes sure your body work like a factory.
The body, like all factories, has to know when to start and stop production of each of its products. When there’s a need for a product, then the factory manager sends a signal that starts production of that product. When enough of the product is made, then the factory manager sends a signal that stops production of the product.
That is similar to what happens in the body. This process is carried out by the endocrine system, which is the body system that communicates and controls functions in the body. This control is maintained through chemical messengers called hormones that are released by glands, or cells or organs that secrete.
Want an example of a hormone? Let’s discuss one that many people wish they could consciously control. Leptin is a hormone that indicates you are full and no longer hungry. This is often referred to as the satiety hormone. Being able to control the release of leptin would make weight loss much easier. We would all be able to release this hormone and no longer feel like we’re hungry. No more overeating!
Control Glands
There are several glands located throughout the body, and all of them are important. However, there are two glands in the brain that are like the masterminds of the other organs. The hypothalamus is a lot like the operations manager in a factory that makes sure every aspect of the factory is functioning optimally. The hypothalamus is a small gland in the brain that assesses the body’s environment and releases hormones that control other glands. The hypothalamus essentially coordinates and dictates the activities of all other glands in order to keep the body functioning properly.
The other major gland in the brain is the pituitary gland. This is the gland that controls the rest of the endocrine system. This may start to seem like the body factory has two operations managers. The pituitary gland does control the rest of the endocrine system, but it does so under the direction of the hypothalamus. So the operations manager, or hypothalamus, tells the production manager, or pituitary gland, when production of the different hormones should start and stop. The pituitary gland is divided into the anterior and posterior pituitary glands.
Glands Controlled by the Pituitary Glands
Our first set of glands in the body are the ones controlled by the anterior pituitary gland. Let’s look at each of these now.
The thyroid gland is the gland located in the neck between the larynx and trachea. Hormones are secreted by the thyroid when the anterior pituitary gland, or production manager, sends the signal to start production. The thyroid hormones directly affect metabolism and indirectly affect blood calcium levels.
The adrenal glands are the triangle-shaped glands that sit on top of the kidneys. There are two sections of the adrenal glands: the adrenal cortex and adrenal medulla. Only the adrenal cortex responds to the anterior pituitary gland. The hormones released by the adrenal cortex control blood pressure, the immune system, and energy conversion. The hormones of the adrenal medulla are released in response to stress.
The last pair of glands that are under control of the pituitary gland are the gonads or sex glands, which are glands that secrete sex hormones. We’ll look at each of these separately, since they are different in males versus females.
Ladies first! The small, oval-shaped pair of female gonads are the ovaries, which secrete two different hormones that control the female reproductive cycle and the process of puberty.
The oval-shaped male gonads located in the scrotum are the testes. A hormone to control the development of male body characteristics is released by the testes when the production manager sends production signals to the testes.
Glands Not Controlled by the Pituitary Glands
Another gland that is located in the brain is the pineal gland, also sometimes called the third eye. It gets that nickname because it is activated based on signals from the optic nerve. So this gland isn’t really part of the factory that works together. The pineal gland is a gland shaped similar to a corn kernel and secretes several hormones. The pineal gland hormones affect secretion of hormones from the ovaries and a person’s sleep-wake cycle.
Our next gland is the parathyroid gland, which is the gland that surrounds the thyroid glands. The parathyroid gland is composed of four tiny glands that secrete PTH, which controls the blood calcium levels, allowing the muscular and nervous systems to function optimally. Parathyroid action is controlled by changes in calcium levels in the blood and does not change in response to another gland.
The pancreas is the flat gland attached to the small intestines behind the stomach that regulates blood glucose levels. Activation of the pancreas is controlled by detection of changes in blood glucose levels. Maintaining blood glucose levels is vitally important in order for the body to function as it should.
The final gland we are going to discuss is the thymus. The thymus is a two-lobed gland located in the upper chest between the lungs. Now that you are an adult, you don’t have any use for this gland, and in fact, it has diminished since you hit puberty. A group of hormones are released by the thymus that make the T-cells of the immune system develop. This gland is of the utmost importance in causing the immune system to develop.
Types of Hormones
Glands are one part of the endocrine system, but the other components of this system are the hormones. There are various types of hormones.
Steroid hormones are the cholesterol-based chemical messengers. Some steroid hormones make up sex hormones and others are classified as corticosteroids that are released by the adrenal cortex. There are also synthetic male sex hormones called anabolic steroids. Anabolic steroids have the same effect in the body as the male sex hormone.
The last type of hormone is the neurohormone. These are hormones that are released by the nervous system that are able to affect glands in the endocrine system.
Lesson Summary
You should have some insight into the endocrine system at this point. This is the body system that communicates and controls functions in the body. We learned that chemical messengers are hormones. Glands are groups of cells or an organ that secrete substances. We looked at leptin, the hormone that lets you know you are full, as an example of a hormone. This is also called the satiety hormone.
The two glands in the brain that control other glands are the hypothalamus and pituitary gland. The hypothalamus is the gland in the brain that controls the actions of almost all other glands. The pituitary gland is the gland below the hypothalamus that controls most other glands in the rest of the endocrine system. This is divided into the anterior and posterior pituitary glands.
We then covered the following glands that are controlled by the anterior pituitary gland:
- Thyroid gland – the gland in the neck between the larynx and trachea that controls metabolism
- Adrenal glands – the glands that sit on top of the kidneys that control blood pressure, the immune system, energy conversion, and stress
- Gonads or sex glands – glands that secrete sex hormones
- Ovaries – female gonads that control the female reproductive cycle and puberty
- Testes – male gonads that cause development from male body characteristics
The other glands covered in this lesson include:
- Pineal gland – gland in the brain that secretes several hormones in response to the optic nerve
- Parathyroid gland – gland surrounding the thyroid gland that controls blood calcium
- Pancreas – gland attached to the small intestines that regulates blood glucose levels
- Thymus – gland in the upper chest between the lungs that causes development of T-cells
The last thing that we discussed that you should now know are the types of hormones. Steroid hormones are cholesterol-based chemical messengers. Anabolic steroids are synthetic male sex hormones, and neurohormones are hormones released by the nervous system.
Lesson at a Glance
The endocrine system is responsible for communicating and controlling functions throughout the body. With the help of glands, hormones are released that sends messages to start, stop, or continue a particular function.
Learning Outcomes
After reviewing this lesson, you should be able to:
- Identify the function of the endocrine system
- Name glands controlled by the hypothalamus and by the pituitary gland
- Describe the function of other glands in the body
- Explain the function of hormones
Medical Disclaimer: The information on this site is for your information only and is not a substitute for professional medical advice.
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Create your account