7.7 Interactions of Organ Systems

Created by CK-12 Foundation

Figure 7.7.1 Everyone on a baseball team has a special job. 


Every player on a baseball team has a special job. In the Figure 7.7.1 collage, each player has their part of the infield or outfield covered in case the ball comes their way. Other players on the team cover different parts of the field, or they pitch or catch the ball. Playing baseball clearly requires teamwork. In that regard, the human body is like a baseball team. All of the organ systems of the human body must work together as a team to keep the body alive and well. Teamwork within the body begins with communication.

Communication Among Organ Systems

Communication among  is vital if they are to work together as a team. They must be able to respond to each other and change their responses as needed to keep the body in balance. Communication among organ systems is controlled mainly by the  and the .

The autonomic nervous system is the part of the that controls involuntary functions. The autonomic nervous system, for example, controls heart rate, blood flow, and digestion. You don’t have to tell your heart to beat faster or to consciously squeeze muscles to push food through the digestive system. You don’t have to even think about these functions at all! The autonomic nervous system orchestrates all the signals needed to control them. It sends messages between parts of the nervous system, as well as between the nervous system and other organ systems via chemical messengers called neurotransmitters.

The endocrine system is the system of  that secrete directly into the bloodstream. Once in the , endocrine hormones circulate to cells everywhere in the body. The endocrine system itself is under control of the nervous system via a part of the brain called the . The hypothalamus secretes hormones that travel directly to cells of the , which is located beneath it. The pituitary gland is the master gland of the endocrine system. Most of its hormones either turn on or turn off other. For example, if the pituitary gland secretes thyroid-stimulating hormone, the hormone travels through the circulation to the thyroid gland, which is stimulated to secrete thyroid hormone. Thyroid hormone then travels to cells throughout the body, where it increases their metabolism.

Examples of Organ System Interactions

An increase in cellular metabolism requires more . Cellular respiration is a good example of organ system interactions, because it is a basic life process that occurs in all living .

Cellular Respiration

Cellular respiration is the intracellular process that breaks down glucose with oxygen to produce carbon dioxide and energy in the form of molecules. It is the process by which cells obtain usable energy to power other cellular processes. Which organ systems are involved in cellular respiration? The needed for cellular respiration comes from the  via the . The oxygen needed for cellular respiration comes from the  also via the cardiovascular system. The carbon dioxide produced in cellular respiration leaves the body by the opposite route. In short, cellular respiration requires — at a minimum — the digestive, cardiovascular, and respiratory systems.

Fight-or-Flight Response

The well-known  is a good example of how the and control other organ system responses. The fight-or-flight response begins when the nervous system perceives sudden danger, as shown in the Figure 7.7.2 diagram. The brain sends a message to the endocrine system (via the pituitary gland) for the adrenal glands to secrete the hormones cortisol and adrenaline. These hormones flood the circulation and affect other organ systems throughout the body, including the cardiovascular, urinary, sensory, and digestive systems. Specific responses include increased heart rate, bladder relaxation, tunnel vision, and a shunting of blood away from the digestive system and toward the muscles, brain, and other vital organs needed to fight or flee.

The fight or flight response
Figure 7.7.2 How the fight-or-flight response occurs.

Playing Baseball

The people playing baseball in the opening collage (Figure 7.7.1) are using multiple organ systems in this voluntary activity. Their are focused on observing and preparing to respond to the next play. Their other systems are being controlled by the . The players are using the , , , and . Can you explain how each of these organ systems is involved in playing baseball?

Feature: Reliable Sources

Teamwork among organ systems allows the human organism to work like a finely tuned machine — at least, it does until one of the organ systems fails. When that happens, other organ systems interacting in the same overall process will also be affected. This is especially likely if the affected system plays a controlling role in the process. An example is type 1 diabetes. This disorder occurs when the pancreas does not secrete the endocrine hormone . Insulin normally is secreted in response to an increasing level of in the blood, and it brings the level of glucose back to normal by stimulating body cells to take up insulin from the blood.

Learn more about type 1 diabetes. Use several reliable Internet sources to answer the following questions:

  1. In type 1 diabetes, what causes the to fail to produce insulin?
  2. If type 1 diabetes is not controlled, which organ systems are affected by high blood glucose levels? What are some of the specific effects?
  3. How can blood glucose levels be controlled in patients with type 1 diabetes?

7.7 Summary

  • The human body’s organ systems must work together to keep the body alive and functioning normally, which requires communication among systems. This communication is controlled by the and . The autonomic nervous system controls involuntary body functions, such as heart rate and digestion. The endocrine system secretes hormones into the blood that travel to body cells and influence their activities.
  • is a good example of organ system interactions, because it is a basic life process that happens in all living cells. It is the intracellular process that breaks down glucose with oxygen to produce carbon dioxide and energy. Cellular respiration requires the interaction of the , , and systems.
  • The is a good example of how the and systems control other organ system responses. It is triggered by a message from the brain to the endocrine system and prepares the body for flight or a fight. Many organ systems are stimulated to respond, including the cardiovascular, respiratory, and digestive systems.
  • Playing baseball — or doing other voluntary physical activities — may involve the interaction of nervous, muscular, skeletal, respiratory, and cardiovascular systems.

7.7 Review Questions

  1. What is the autonomic nervous system?
  2. How do the autonomic nervous system and endocrine system communicate with other organ systems so the systems can interact?
  3. Explain how the brain communicates with the endocrine system.
  4. What is the role of the pituitary gland in the endocrine system?
  5. Identify the organ systems that play a role in cellular respiration.
  6. How does the hormone adrenaline prepare the body to fight or flee? What specific physiological changes does it bring about?
  7. Explain the role of the muscular system in digesting food.
  8. Describe how three different organ systems are involved when a player makes a particular play in baseball, such as catching a fly ball.
  9. What are two types of molecules that the body uses to communicate between organ systems?
  10. Explain why hormones can have such a wide variety of effects on the body.

7.7 Explore More

3D Medical Animation – Peristalsis in Large Intestine/Bowel ||
©Animated Biomedical Productions (ABP), 2013.

Adrenaline: Fight or Flight Response, Henk van ‘t Klooster, 2013.

Fight or Flight Response, Bozeman Science, 2012.



Figure 7.7.1

Figure 7.7.2

The_Fight_or_Flight_Response by Jvnkfood (original), converted to PNG and reduced to 8-bit by Pokéfan95 on Wikimedia Commons is used under a CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/deed.en) license.


Animated Biomedical Productions. (2013, January 30). 3D Medical animation – Peristalsis in large intestine/bowel || ©ABP. YouTube. https://www.youtube.com/watch?v=Ujr0UAbyPS4&feature=youtu.be

Bozeman Science. (2012, January 9). Fight or flight response. YouTube. https://www.youtube.com/watch?v=m2GywoS77qc&feature=youtu.be

Henk van ‘t Klooster. (2013). Adrenaline: Fight or flight response. YouTube. https://www.youtube.com/watch?v=FBnBTkcr6No&t=4s

Mayo Clinic Staff. (n.d.). Type 1 diabetes. MayoClinic.org. https://www.mayoclinic.org/diseases-conditions/type-1-diabetes/symptoms-causes/syc-20353011

Wikipedia contributors. (2020, July 22). Thyroid-stimulating hormone. In Wikipedia. https://en.wikipedia.org/w/index.php?title=Thyroid-stimulating_hormone&oldid=968942540


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Human Biology Copyright © 2020 by Christine Miller is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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