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The Function of the Endocrine System - Glands and hormones

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The Function of the Endocrine System - Glands and hormones

Andre the Giant [+] Biopsychology [+] StudySmarter Originals.Andre the giant, shepard-fairey-content-marketing.

Andre the Giant was a French wrestler and actor that became internationally known for his awesome height. Being around 7 feet tall and continually growing through his life, he was immortalised in Hollywood films like The Princess Bride and by street artist Sheppard Fairy’s logo for the brand Obey. Andre was so tall because of a hormonal imbalance called acromegaly, which caused his cells to never stop growing. When acromegaly impacts height, it’s called gigantism.

Although being tall might seem practical when you’re trying to change a lightbulb, gigantism comes with many health issues that, if left untreated, can decrease life expectancy. This happened to Andre; he died at the age of 46 from complications caused by hormone imbalances.

Andre is an example of the importance of the endocrine system, the bodily system that controls hormones, for living beings. Let’s take a look at what the endocrine system does and how it works.


What is the definition of the Endocrine System?

The endocrine system ( pronounced “enn-dough-krynn”) is the system responsible for the production and transmission of information in the body via messenger substances called hormones. These are produced in specialised organs called glands as well as in endocrine cells located in various organs throughout the body.

What are hormones?

Hormones are chemical molecules that pass on information in the body. 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. Effector means the area or organ in the body that the chemical affects. Once released into the bloodstream, hormones keep on circulating in the body until broken down by the liver and kidneys.


What are the two types of hormones?

There are many different hormones, but they can be split into two types- hydrophilic, meaning “water-friendly” or lipophilic, meaning “fat-friendly”. This is important because the cell membrane is made of lipids (or fats), so if a hormone is lipophilic, it can go straight into the cell, whereas hydrophilic hormones can’t.

  • Hydrophilic: Hydrophilic hormones are set off by binding to receptors on the outside of the cell membrane and causing protein reactions called second messenger reactions. These are usually complex chain reactions that result in regulatory processes in the body. An example of a hydrophilic hormone is melatonin, which influences when we sleep.

  • Lipophilic: Lipophilic hormones are made of fat (phospholipid) molecules just like the cell membrane, so they don’t need to use receptor gates. They just enter the cell with their “all-access pass” and affect cell DNA processes in the nucleus, including long-term developmental processes. An example of a lipophilic hormone is testosterone, which controls male sperm production, fat and muscle distribution as well as libido.

Hormones influence all aspects of the body. Let’s look at some of the effects that hormones can have, called endocrine functions.

What are endocrine functions?

Hormones can have very extreme and varied consequences, called endocrine functions. Some of the different areas that hormones influence are:

Melatonin: The sleep-wake cycle

Growth Hormone: Cell growth and restoration

Stress hormones: (Glucocorticoids, adrenaline/noradrenaline): the fight-or-flight response

Histamine: Inflammation

Thyroxin: Metabolism or the rate at which calories are burnt

ADH: Water and salt intake and output

Oxytocin: Social bonding

Testosterone: Male-stereotypical features, such as hair and muscle growth

Oestrogen: Female-stereotypical features such as breasts, menstruation

Study tip: You don’t have to learn all the different hormones for your exam, it’s enough to have a rough idea of how they work. The exam specification emphasises stress hormones in particular so we’ll have a closer look at them.

The body has to counteract many hormonal effects with other hormones in order to restore homeostasis or biological balance. If hormones can’t be regulated, it can cause life-long illnesses like diabetes or even tumors. Some imbalances require lifelong treatment with artificial hormones, like insulin for type 1 diabetes.

One example of a hormone that requires up- and down regulation is Growth hormone (GH) which is the hormone that Andre the giant had too much of. Growth hormone stimulates cell growth, meaning it’s important for rest and recuperation of muscles and the brain.

What are glands and what are the two types of glands?

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

  • Exocrine glands: If a gland produces a substance that isn’t a hormone, it’s an exocrine gland. Tear ducts and salivary glands are examples of exocrine glands.

  • Endocrine glands: If a gland produces a hormone, it’s an endocrine gland.

Examples of endocrine glands are the thyroid or ovaries/testes.

What are the endocrine system organs?

Major endocrine glands, training.seer.cancer.gov

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

  • Thyroid

  • Thymus

  • Pituitary gland

  • Pineal gland

  • Pancreas

  • Testes or Ovaries depending on your biological sex.

  • Adrenal glands

Some hormones’ only function is to stimulate the releasing 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 directly affect organs- these are called direct action hormones or effector hormones.

What is the endocrine master gland?

One of the most important glands is located in the brain. This is the pituitary gland, also called the master gland. It controls the production and secretion of many other hormones. Part of it, the posterior pituitary gland, is an extension of the part of the brain called the hypothalamus.


The other part, the anterior pituitary gland, is strictly speaking not part of the brain, but it connects to it 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.

It’s a bit like if you ordered a new games console for a friend on Amazon. You (the hypothalamus) tell Amazon through one website what you want (pituitary). They coordinate with sellers and warehouses in different countries (target glands). These sellers pack and send packages to your friend’s delivery address (effector organs). Now they have no more excuses and can get to playing (effect).


What is the difference between the endocrine and nervous system?

Both the nervous system and the endocrine system are responsible for the passing on of information, for responding to stimuli and for creating homeostasis (biological balance) in the body. However, they are different in that the endocrine system is slower to react than the nervous system, and the changes that hormones affect are powerful and long-lasting.

Some hormones (the transmitters used by the endocrine system) have similar molecular structures or even work in a similar fashion to neurotransmitters (used by the nervous system), but their functions are different. For instance, noradrenaline is a neurotransmitter that the body uses as both neurotransmitter and hormone and it’s chemically closely related to the hormone adrenaline.

Let’s have a closer look at the differences between:

Electrochemical vs. chemical

The nervous system’s preferred method of communication is electrochemical impulses called action potentials. Neurotransmitters chemically bind to proteins on the cell membrane to allow electrically charged ions to pass through, which generates electrical charge. If enough of this electrical charge accumulates, an electrical impulse is passed to the next cell via action potentials.

Hormones don’t generate charge, their communication is purely chemical. They either influence protein production processes or set off chain reactions involving proteins called second messenger cascades.

Fast vs. slow

The nervous system sends electrochemical impulses (called action potential via the nervous system that travel quickly at around 70-120 metres per second. If a person were to continually send impulses, they’d be seriously incapacitated. This is what happens when a person has an epileptic convulsion- the neurons in the brain keep continually firing. Hormones on the other hand stay in the bloodstream for extended amounts of time and only stop affecting changes when they are broken down again or counteracted by a different hormone.

Short-distance vs. long distance

Whereas neurotransmitters usually only work and are broken down or reused locally near the synapse where they were released, hormones travel through the entire body and carry messages to faraway organs. Hormones can affect many organs at once, like in the case of the fight-or-flight response.

Fight-or-flight situations cause stress hormones to be released into the body. Let’s have a look at what happens in the endocrine system when the body reacts to stress.

What are stress hormones?

Let’s suppose I told you you had to give a presentation in front of your whole grade level with only five minutes to prepare. Stressful, right? When you’re about to step on the stage you’d expect to get “nervous”- your heart to beat faster, to sweat or your voice to shake, to turn red and maybe you feel the urgent need to run to the nearest bathroom.

When the brain consciously or unconsciously decides that a person is in a dangerous situation, the body produces a number of stress hormones in the adrenal glands which sit atop the kidneys. These stress hormones include cortisol, adrenaline and noradrenaline. Adrenaline is produced in the core of the adrenals, called the medulla. Another name for adrenaline is epinephrine- which is used in “epi-pens” (first aid for allergic shock) and some asthma inhalers.

How do hormones contribute to creating the physical symptoms that in everyday life are called “stage fright” or “nerves”?

1. Once you consciously or subconsciously perceive something to be scary, the hypothalamus, which is part of the brain/nervous system, produces a hormone called CRF (corticotropin releasing factor - factor is a particular type of hormone).

2. CRF sends the order to the pituitary gland to produce another hormone, ACTH (adrenocorticotropin).

3. ACTH is released by the pituitary gland into the bloodstream where it travels throughout the body to the target gland- the adrenal glands that are located far away on top of the kidney.

4. As a consequence, the adrenal glands produce stress hormones, including the stress hormone adrenaline.

5. Adrenaline gets released into the bloodstream, which in turn affects many effector organs in the body.

6. The effector organs react- the heart starts beating fast, breathing gets deeper, sweat glands produce sweat and bowel movements are initiated.


The Function of the Endocrine System - Glands and hormones - Key takeaways

  • The endocrine system is responsible for transferring information via messenger molecules called hormones.
  • The function of the endocrine system is long-term and long-lasting regulation of biological processes.
  • The goal of hormones is homeostasis or biological balance.
  • Glands are specialised organs that produce substances in the body.
  • There are two types of glands: exocrine glands that produce non-hormone substances and endocrine glands that produce hormones.
  • Endocrine glands are organs specialised in producing hormones and there are 7 of them in an individual (non-intersex); thyroid, thymus, pituitary gland, pineal gland, pancreas, testes/ovaries and adrenal glands.
  • Hormones aren’t only produced in endocrine glands, they can also be produced in specialised cells found in many organs of the body.
  • Adrenaline is one of the hormones produced in the adrenal glands in response to stress. The effects of adrenaline include increasing heart rate, deeper breathing, sweating and gastrointestinal symptoms.



Frequently Asked Questions about The Function of the Endocrine System - Glands and hormones

The endocrine system is one of the bodily systems that specialise in passing on information.

The endocrine system regulates biological processes in the long-term.

The endocrine system uses messenger substances called hormones to create a chain of effects.

Both the endocrine system and the nervous system are in charge of communication in the body. The nervous system works quicker but the hormone system changes last longer.


The adrenal gland is an endocrine gland (organ specialising in hormone production) that produces stress hormones. 


Final The Function of the Endocrine System - Glands and hormones Quiz

Question

What's the main function of the endocrine system?




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Answer

The main function of the endocrine system is 

transmission of information to effect long-lasting changes.

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Question

What are the substances called that are produced by the endocrine system?



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Answer

Hormones are the substances produced by the endocrine system.

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Question

What are the organs called that are affected by neurochemicals?




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Answer

Effectors or effector organs are the 

organs affected by neurochemicals.

Show question

Question

What are hormones?



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Answer

Hormones are molecules that regulate biological processes and rhythms.

Show question

Question

What are the two main categories of hormones?



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Answer

The two main categories of hormones are hydrophilic and lipophilic

Show question

Question

True or False- hormones have one function in the body.



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Answer

False- they have many varied functions.

Show question

Question

Which of these is not a hormone function


a. urine intake

b. mother-child bonding

c. development of biological sex attributes

d. weight gain or loss



Show answer

Answer

The answer is a urine intake

Urine intake is not a hormone function. Urine output is a function of the endocrine system, as water and salt levels are controlled by ADH. 

Mother-child bonding is influenced by oxytocin, sexual attributes are controlled by testosterone and estrogen, and weight gain or loss can be influenced by thyroxine, which controls the rate at which the body burns calories.


Show question

Question

What are glands?




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Answer

Glands are any kind of organs in the body that produce substances.

Show question

Question

True or false tear ducts and salivary ducts are endocrine glands.




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Answer

False- tear or salivary ducts are exocrine glands.

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Question

 How many endocrine glands does a human usually have?



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Answer

Unless a person is intersex (meaning they're born with female and male genitals) humans usually have 7 endocrine glands.


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Question

What's an effector?




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Answer

Effector is the organ that a substance works on, it’s the receiver of an effect.

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Question

 True or false hormones can have as their only function to initiate hormone production in target glands.



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Answer

True- the indirect action hormones are hormones that instruct only the production of more hormones.


Show question

Question

 True or false indirect action hormones are also called effector hormones. 



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Answer

False- effector hormones work directly on the body, so they are direct action hormones.


Show question

Question

True or false, the anterior pituitary gland is part of the brain. 



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Answer

False, the posterior pituitary gland is part of the brain.

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Question

Which hormones are the stress hormones?





Show answer

Answer

There are a number of stress hormones including adrenaline, noradrenaline and cortisol.

Show question

Question

What is the main effect caused by adrenaline?



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Answer

Adrenaline raises the heart rate, opens the breathing pathways, causes sweating and bowel movement and increases circulation.


Show question

Question

Which organs of the body break down hormones?




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Answer

The liver and kidney break down 

hormones in the bloodstream.

Show question

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