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How the Body Works: Overview of Organ Systems

Updated on May 14, 2019

If you want to be relatively free of the fear of not knowing enough about your health that you have to rely on others to make big decisions for you, it's critical that you take some time to learn about how your body works.

The goal of this series of articles is to give you a broad look at the major organ systems in your body and how they work together to keep you well. As you read this series, I encourage you to adopt the mindset of having to learn this material well enough to teach it to a group of junior high school students - this mindset should lead to an excellent understanding of how to care for your health.

Before we look at the major organ systems that work to keep you well, let's first review some basic definitions.

You're likely familiar with most or all of the major organs in your body. Your brain, heart, lungs, kidneys, stomach, liver, gall bladder, spleen, and pancreas are well known examples of organs. Less well known as organs are your bones and skin.

Your organs are collections of specialized tissues, and your tissues are collections of groups of cells. So in reverse order, a simple, big picture look at your anatomical make-up looks like this:

Your cells are the basic living units that make up your body.

Groups of cells come together to form specialized tissues.

Groups of tissues come together to form your organs.

This bird's eye view of your physical make-up is important because it highlights the following point:

The health of every organ in your body is determined by the health of the cells that make up your organs. When the majority of cells that make up any organ in your body are healthy, that organ is likely to be healthy; the converse is true as well - when most of the cells that make up one of your organs are dysfunctional or diseased, that organ is likely to be dysfunctional.

Given all of the above, it makes sense, then, that taking care of your organs requires that you take care of your cells.

The most important determinant of the health of every cell in your body is the quality of blood that is supplied for ongoing nourishment and removal of waste products. The blood that your heart pumps to all of your cells delivers nutrients and oxygen to fuel ongoing energy production within your cells. Steady blood flow also ensures regular removal of waste materials from your cells, which keeps your cells uncluttered and free to function properly.

The cells that make up your heart are no different than the rest of the cells in your body - your cardiac cells also require a steady supply of blood, nutrients, and oxygen, and your cardiac cells receive these things via your coronary arteries. So just as your heart delivers nutrients and oxygen to the cells of your kidneys, stomach, and liver, your heart also delivers nutrients and oxygen to its own cells.

If, over time, your coronary arteries become damaged and less capable of delivering a steady supply of blood to the cells of your heart, you may experience chest pain, shortness of breath, and other symptoms that are typical of a heart attack. Heart attacks are usually caused by some degree of blockage in the coronary arteries. If the cells of your heart don't receive steady, quality blood flow, your heart will eventually lose its capacity to pump blood, nutrients, and oxygen to the rest of your body.

The main point here is this: all of the cells that make up the many organs in your body have the same basic requirements to stay healthy, with the first and most important requirement being steady blood flow. Clearly, the healthier your diet and lifestyle are, the healthier your blood will be. And the healthier your blood is, the healthier your cells will be.

It's true that certain foods and substances are known to have specific effects on specific organs. For example, we know that eating foods that are rich in the omega-3 fatty acid, DHA, is good for promoting optimal brain function. We also know that eating foods that are rich in vitamin D can help promote healthy bones and teeth. But it's incorrect to think that these nutrients produce only these specific results. When you eat foods that are rich in DHA and vitamin D, these nutrients touch all of your cells, not just the cells that make up your brain, bones, and teeth.

In the same vein, when you expose yourself to prescription drugs, recreational drugs, and other environmental pollutants, all of your cells are touched - there is no such thing as a "side" effect.

So now that we've hammered home the principle that the health of your organs is determined by the health of your cells, and that the health of your cells is determined by all of your daily food and lifestyle choices, let's move on to an overview of your organ systems.

You have eleven organ systems that govern all of your physiological activities. They are as follows:

  1. Nervous System

  2. Endocrine System

  3. Cardiovascular System

  4. Respiratory System

  5. Digestive System

  6. Urinary System

  7. Muscular System

  8. Skeletal System

  9. Integumentary (Skin) System

  10. Immune System (includes Lymphatic System)

  11. Reproductive System

Aside: Not included in any of the organ systems listed above are "special sense" organs that you need to see, hear, smell, taste, and maintain your balance.

Each of your organ systems are groups of organs that work together to carry out specific duties in your body. For example, your digestive system is an organ system that requires contributions from a number of organs, including your stomach, small intestine, large intestine, liver, pancreas, and gall bladder; all of these organs work together to digest the foods that you eat, and transfer the nutrients in the foods that you eat from your small intestine to your cells.

Some organs contribute essential work to more than one organ system. For example, your pancreas plays an important role within your digestive system by secreting digestive enzymes into your small intestine, but your pancreas is also an irreplaceable component of your endocrine system, as it produces three important hormones that are secreted into your bloodstream and have system-wide effects.

Finally, it's important to point out that all of your organ systems affect one another. We've already looked at one example of this: Your cardiovascular system keeps all of your other organ systems going by supplying blood, nutrients, and oxygen to all of your cells.

Here are more examples that illustrate the interdependence of your organ systems:

  • All of your organ systems are regulated by your nervous and endocrine systems - these two systems are co-directors of all of your body's moment-to-moment activities.

  • Your urinary system is essential to maintaining fluid and pH balance within all of your organ systems.

  • Your respiratory system brings in the oxygen that your cardiovascular system delivers to all of your cells. Your respiratory system also plays a vital role in maintaining your blood pH.

  • Your integumentary (skin) and immune systems play critical roles in preventing life-threatening infections of all of your other organ systems.

  • Your muscular system allows you to move (making the rest of your organ systems relevant to your existence). Your muscular system also serves as an important reservoir for your endocrine system.

  • Your skeletal system provides physical protection and structural support for your other organ systems.

  • And perhaps the most obvious example: Your digestive system provides fuel for all of your other organ systems to use to produce energy.

We'll look at each of your organ systems in more detail in future articles in this series on how your body works.

Here are the main points to take away from this article:

  1. All of your organs are influenced by all of your food and lifestyle choices. There's virtually no way to affect just one organ system via a specific diet or therapy. Whenever one of your organ systems improves or declines in health, the rest of your organ systems follow suit to some degree.

  2. The health of each of your organs is determined by the health of the cells that make up your organs. And all of your cells have the same basic requirements to stay healthy.

If you're not yet subscribed to our newsletter, and you'd like to be notified whenever a new article in this series is published, be sure to sign up below.

And if you'd like some concrete guidelines on how to optimally care for the cells that make up your organ systems, please feel free to view the following resources:

Full Body Cleanse

Main Causes of Disease and Dysfunction

Related Posts:

How the Body Works: Overview of the Nervous and Endocrine Systems

How the Body Works: Overview of the Integumentary System (Skin)


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