System Of Organs: Definition and FAQs

Jul 11, 2022 | Turito Team

system of organs

System of organs

Suppose you were a single-celled organism and lived in a nutrient-rich place; surviving would be pretty straightforward. Let us assume you were an amoeba living in a pond; you could take nutrients from your environment straightforwardly. The oxygen needed for your metabolism could disseminate across the cell membrane, and waste products like carbon dioxide could move out. When it was time to reproduce, you could just split up in two!

However, the truth is that you are not an amoeba—given that you’re reading this blog right now—and things are not so simple for big, multi-celled organisms like humans. Your complex body comprises over 30 trillion cells, most of which aren’t in direct contact with the external environment.

A cell that lies deep inside your body, like in one of your bones or liver, can’t derive the nutrients or oxygen it requires from the environment. How does the body nourish its cells and keep itself running then? Let us look closely at how your body’s organisation makes this possible.

Most cells in complex multicellular organisms do not directly exchange substances such as nutrients and wastes with the external environment. Instead, they have an internal environment of extracellular fluid adjacent to them, that is, fluid outside of cells. The cells derive the necessary nutrients from this extracellular fluid and put waste materials into it. Humans and other multicellular living beings are composed of specialised systems that efficiently maintain the environment inside the body, keeping it stable and capable of providing for the requirements of the cells.

Different functions are carried out by different systems of the body. Suppose your digestive system is responsible for ingesting the food and processing it. In contrast, your pulmonary system—in collaboration with your circulatory system—is responsible for taking oxygen and releasing carbon dioxide. The muscular and skeletal systems are important for movement; the reproductive system controls reproduction, and the excretory system disposes of metabolic waste.

Due to their specialisation, these different systems are interdependent. The cells constituting the organs of the digestive system, muscular, skeletal, reproductive, and excretory systems all require oxygen from the respiratory system to perform their functions, and the cells native to the respiratory system and other systems all require nutrients and need to dispose of metabolic wastes. All the body systems function in collaboration to keep the organism functioning.

Overview of body organisation

All living organisms are composed of one or more cells. Unicellular organisms, such as amoebas, have a single cell. Multicellular organisms, such as humans, have many cells. Cells are known as the basic units of life. The cells in multicellular organisms like human beings combine to form tissues. Tissues are a collection of similar-looking cells that work in collaboration toward a particular task. Organs are structures composed of two or more tissues responsible for carrying out a common function. Groups of organs with the same kind of functions constitute different organ systems.

At every organisation level—cells, tissues, organs, and organ systems—structure is closely associated with function. For example, cells of the small intestine that are responsible for absorbing nutrients appear very different from the muscle cells responsible for body movement. The structure of the heart is related to its job of pumping blood and supplying it throughout the body. In contrast, the structure of the lungs is related to the take up of oxygen and the release of carbon dioxide into the atmosphere.

All the organ systems of humans have particular functions to perform. For example, the digestive system, the cardiovascular system, and the musculoskeletal system all perform specific functions.

The digestive system, which extends from the mouth to the anus, executes the function of receiving and digesting food and disposing of the waste. This system consists of the mouth, the stomach and the intestines, which carry and absorb food. It also consists of accessory organs of the digestive system like the pancreas, liver, and gallbladder, which secrete digestive enzymes, eliminate toxic products, and store chemicals necessary for digestion.

The cardiovascular system consists of the heart and blood vessels, which are responsible for pumping and circulating blood.

The musculoskeletal system consists of the bones, ligaments, tendons, and joints, which are responsible for supporting the body and assisting in locomotion.

Organ systems working together

Organ systems collaborate with each other to perform complicated tasks. For instance, after consuming a large meal, many organ systems collaborate to enable the accessory organs of the digestive system to obtain more blood to carry out its functions. The organs of the digestive system require help from the heart system and the nervous system. Arteries of the digestive tract dilate to transport more blood. Nerve signals are carried to the brain, informing it of the enhanced digestive workload.

The heart is even directly stimulated by the accessory organs of the digestive system via nerve impulses and chemicals given off into the bloodstream. The heart helps by pumping more blood. The brain aids by inhibiting hunger, promoting fullness, and decreasing inclination toward vigorous physical activity. This preserves more blood to be utilised by the digestive system instead of other body systems.

Integration between organs and organ systems is very important as it allows the body to assign a function to each organ based on the entire body’s demands. In the scenario above, the heart must be aware of when the organs of the digestive system require ample blood to pump more. When the heart is aware of when the body is at rest, it can pump less blood. The kidneys have to know when there is too much fluid in the body so that they can excrete more urine. Also, they should know when the body is dehydrated so that they can save water.

The autonomic nervous system mainly regulates the complex communication network that maintains bodily functions. This part of the nervous system acts without the effort of a person. Certain chemicals called neurotransmitters propagate signals between different parts of the nervous system and between the nervous system and other organs.

The endocrine system comprises several glands that release chemical transmitters known as hormones. Hormones navigate to other organs via the bloodstream and control their functions. For instance, the thyroid gland secretes thyroid hormone, which regulates the metabolic rate. The pancreas releases insulin, which regulates the use of sugar.

One of the most important neurotransmitters is the well-known hormone adrenaline. It is released from the adrenal glands when a person is suddenly stressed or frightened. Within moments of its release, the entire body is on alert and responsive. It is called the fight-or-flight response. The heart beats more efficiently, the pupils dilate to let more light in, the breathing pace increases, and the activity of the digestive system reduces to allow more blood into the muscles. The effect is very fast and intense.

Even though other chemical communications are less dramatic, they are equally effective. For example, when the body gets dehydrated and requires more water, the blood volume circulating in the cardiovascular system reduces. Receptors sense this reduced blood volume in the arteries in the neck. They send impulses via the nerves to the pituitary gland lying at the base of the brain, which then releases an antidiuretic hormone. This hormone directs the kidneys to concentrate urine and retain more water. At the same time, the brain perceives thirst, directing a person to drink.

How are organ systems associated with VA Disability Ratings?

Our bodies consist of 11 basic organ systems that regulate all the essential body functions. If these systems are interdependent, they can become out of tune. When one of those is not performing its functions properly, the others try to correct the anomaly. All the systems collaborate in an attempt to produce a phenomenon called homeostasis within the body.

The 11 organ systems are:

  • The lymphatic system
  • The integumentary system
  • The bony or skeletal system
  • The endocrine system
  • The digestive system
  • The respiratory system
  •  The muscular system
  •  The nervous system
  • The reproductive system
  • The CVS
  • The urinary systems.

The VA describes 14 disability systems, which are the same as the body systems. However, the disability systems are described differently for rating. These systems are studied independently when necessary.

Conclusion

Your body comprises eleven organ systems, each specialising in carrying out a specific function. Our organ systems work in collaboration with each other to make activities like digestion, breathing, reproduction etc., possible. When all the organ systems work in synchronisation, the organism functions properly.

Frequently Asked Questions

1. What is homeostasis?

Homeostasis can be defined as the phenomenon by which our body regulates its normal functions. Because organ systems collaborate with each other, the body can maintain stable quantities of internal fluids and substances. Also, the organs always work at a constant rate, and each organ facilitates the functions of every other organ.

2. How is homeostasis maintained?

Communication to maintain homeostasis occurs through the autonomic nervous system and the endocrine system, and special chemicals called neurotransmitters facilitate homeostasis.

3. What is the role of an organ system?

An organ system consists of a group of organs specialised to perform specific bodily functions. Suppose the organs in an organ system called the gastrointestinal system carry out the function of digestion.

4. What is homeostasis?

Homeostasis can be defined as the phenomenon by which our body regulates its normal functions. Because organ systems collaborate with each other, the body can maintain stable quantities of internal fluids and substances. Also, the organs always work at a constant rate, and each organ facilitates the functions of every other organ.

5. How is homeostasis maintained?

Communication to maintain homeostasis occurs through the autonomic nervous system and the endocrine system, and special chemicals called neurotransmitters facilitate homeostasis.

6. What is the role of an organ system?

An organ system consists of a group of organs specialised to perform specific bodily functions. Suppose the organs in an organ system called the gastrointestinal system carry out the function of digestion.


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