Organs in the Body: Definition Anatomy

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Organs are structures that handle specific jobs so your body can function. They often work in teams called organ systems.

What are organs?

Organs are specialized structures in your body that handle specific jobs. Some of the best-known organs are your heart, brain or liver. But many other structures count as organs, too. That includes some you might not think of, like your skin.

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Each of your cells is like an individual worker doing a specific job. Tissues are groups of related cells teamed up in the same place. Organs consist of many tissues that work together cooperatively to accomplish a bigger job.

Organs are part of bigger systems that handle interconnected jobs. And some organs can be part of more than one system. Some examples of organ systems and the organs that are part of them include:

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Organs can be single structures like your heart. But they can also be a group of the same type of structure. For example, your bones are technically an organ, but so is the bone marrow inside most of your bones.

How many organs are there?

You might get a different answer depending on who you ask. Before 2016, the number of organs was widely recognized as 78. But researchers continue to expand modern medicine’s understanding of how the body works. That’s why, if you ask experts today how many organs you have, the answer can range from 78 to 80.

In particular, two discoveries explained in research papers from 2016 and 2018 now have experts split on the true number. The two organs that are gaining acceptance but still have some controversy behind them are:

There’s still a lot of ongoing research into how these organs work and what they do. And advances in technology and medical science may lead to further discoveries.

What are vital organs?

Vital organs are organs that you need to survive. Your body can’t function without them. Some key examples of vital organs include your:

What organs are on one side of the body?

You have several organs that are centered inside your body, while others are clearly to one side.

Some examples of centered organs in your body include your:

Some examples of left-side organs include your:

Pancreas

Stomach

Spleen

Examples of right-side organs include your:

And you have several paired organs, with one on each side of your body. They include your:

Lungs

Kidneys

Eyes

Ears

Reproductive organs, including external ones like testicles and internal ones like ovaries

What organs can I survive without?

You can survive without several organs. They include your:

Appendix

Gallbladder

Ovaries and/or uterus

Spleen

Testicles

Large sections of your bowels or the entire colon

You can also survive with just one of several paired organs, like your lungs or kidneys.

While you can’t survive without your heart or at least one kidney, there are artificial versions that can do their jobs. Artificial hearts can be long-term replacements for damaged or diseased hearts. And dialysis can be a long-term substitute (but not a permanent replacement) for your kidneys.

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What are accessory organs?

Accessory organs are organs that contribute to a body system, but they might not necessarily be a clear part of it. One example is your gallbladder, which contributes to your digestive system. Breasts are another example. They can contribute to your reproductive system during breastfeeding.

But being an accessory organ doesn’t mean that organ isn’t important. Your liver is an accessory organ to your digestive system, but you also can’t live without it.

What is the largest organ in the body?

The largest body organ you have is your skin. It makes up about 15% of your total body weight. But for just your internal organs, the largest is your liver.

A note from Cleveland Clinic

Organs aren’t just something you have inside you. There are plenty of parts on the outside of your body, like your eyes and other facial features, that are organs, too. It can be easy to take them for granted, especially when everything’s working as it should. But if you’re sick and you have an organ issue, it can be hard to think about much else. If you have questions about taking care of your organ health, talk to a healthcare provider. They can offer guidance on how to best take care of your organs and your health overall.

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Experts You Can TrustMedically Reviewed.Last updated on 12/09/2024.

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References

Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

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Experts You Can TrustMedically Reviewed.Last updated on 12/09/2024.

References

Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

Benias PC, Wells RG, Sackey-Aboagye B, et al. Structure and Distribution of an Unrecognized Interstitium in Human Tissues (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869738/) [published correction appears in Sci Rep. 2018 May 10;8(1):7610. doi: 10.1038/s41598-018-25732-x]. Sci Rep. 2018 Mar 27;8(1):4947. Accessed 12/5/2024.

Betts JG, DeSaix P, Johnson JE, et al. Anatomy and Physiology. 2nd ed. Openstax, Rice University; 2022.

Coffey JC, O’Leary DP. The mesentery: structure, function, and role in disease (https://pubmed.ncbi.nlm.nih.gov/28404096/). Lancet Gastroenterol Hepatol. 2016 Nov;1(3):238-247. Accessed 12/5/2024.

Drake RL, Vogl AW, Mitchell AWM. Abdomen. In: Drake RL, Vogl AW, Mitchell AWM, eds. Gray’s Anatomy for Students. 5th ed. Elsevier Inc. 2024:247-409.

Standring S (ed). Gray’s Anatomy. 42nd ed. Elsevier Limited; 2020.

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