Organs in the Human Body (2025)

• Introduction
  • What are organs?
• 10 Most Vital Organs
  • What are the 10 most vital organs?
• COVID-19 Organ Damage
  • Can COVID-19 damage organs?
• Complications of COVID-19
  • Organ damage and associated complications due to COVID-19
• FAQs
  • Frequently asked questions

What are organs?

Anorgan is a collection of tissues that function in a particular manner. The tissue is connected and constructed as a unit to serve a common function. All organs in the body work in sync to form about a dozen organ systems.

When it comes to human anatomy, organs play a vital role in ensuring the proper functioning of the body. Organs are the individual structures that make up organ systems, each with a specific role in maintaining the body’s health. For example, the largest organ in the body is the skin, which serves as a protective barrier and regulates temperature.

These organs function together within various organ systems, such as the digestive system, respiratory system, and circulatory system, to support the body’s overall health and well-being. A human body organs diagram can visually represent how these organs are organized and connected within the body, helping to better understand their functions and relationships.

How many organs are in the human body? Below is the list of all discovered organs to date.

1. Adrenal glands
2. Anus
3. Appendix
4. Bladder (urinary)
5. Bones
6. Bone marrow (spongy part of the bone)
7. Brain
8. Bronchi (tubes in the lungs)
9. Diaphragm (muscle of breathing)
10. Ears
11. Esophagus (food pipe)
12. Eyes
13. Fallopian tubes
14. Gallbladder
15. Genitals
16. Heart
17. Hypothalamus (in the brain)
18. Joints
19. Kidneys
20. Large intestine
21. Larynx (voice box)
22. Liver
23. Lungs
24. Lymph nodes
25. Mammary glands
26. Mesentery (covering of the intestines)
27. Mouth
28. Nasal cavity
29. Nose
30. Ovaries
31. Pancreas
32. Pineal gland
33. Parathyroid glands
34. Pharynx
35. Pituitary gland
36. Prostate
37. Rectum
38. Salivary glands
39. Skeletal muscles
40. Skin
41. Small intestine
42. Spinal cord
43. Spleen
44. Stomach
45. Teeth
46. Thymus gland
47. Thyroid
48. Trachea
49. Tongue
50. Ureters
51. Urethra
52. Uterus
53. Human skeleton
54. Ligaments (connect muscles to bones)
55. Tendons (connect bones to bones)
56. Blood cells
57. Vagina
58. Hair
59. The vestibular system of the ear
60. Placenta
61. Testes
62. Nails
63. Vas deferens
64. Seminal vesicles
65. Bulbourethral glands
66. Penis
67. Scrotum
68. Parathyroid glands
69. Thoracic ducts
70. Arteries
71. Veins
72. Capillaries
73. Lymphatic vessels
74. Tonsils (Waldeyer’s ring of tissues)
75. Nerves
76. Subcutaneous tissue
77. Olfactory epithelium (nose)
78. Cerebellum

What are the 10 most vital organs?

The ten most vital organs are as follows.

1. Skin

• The skin is the largest organ in the human body.
• Its main job is to maintain the body's temperature.
• The skin contains sweat glands and oil glands. Oil released by the skin helps keep the skin from drying out and the hair from becoming brittle.
• The skin also regularly sheds cells to maintain its effectiveness.

2. Brain

• The brain stores information, allows you to think and learn, and controls vital daily functions (such as digestion, heart rate, and breathing).
• The brain receives impulses from nerves, which are located throughout the body, and responds to pain and other stimulation.
• Even though the brain is so important, it is also very delicate. The brain is made of soft tissue and is protected only by the skull; therefore, head injuries can be serious.

3. Heart

• The heart is another vital organ. In an average lifetime, the heart beats more than 2.5 million times.
• The heart's job is to pump oxygenated blood throughout the body and receive deoxygenated blood in return.

4. Kidneys

• The kidneys are located under the rib cage in the lower back.
• The kidneys filter things, such as water and salts, out of the blood and produce urine.
• The kidneys also produce an enzyme called renin. This enzyme plays a big role in regulating blood pressure.

5. Liver

• The liver is in the upper abdomen, slightly to the left.
• The main job of the liver is to produce bile, which it sends to the stomach for digestion.
• The liver also filters out toxins and regulates blood sugar.
• Blood sugar is regulated by the liver, which converts and stores sugar and releases it as needed into the bloodstream.
• The liver is also in charge of releasing cholesterol, breaking down fats, and producing blood proteins. It is the largest internal organ.

6. Pancreas

• The pancreas is located behind the stomach.
• The job of the pancreas is to produce enzymes necessary for digestion and send them to the stomach.
• The pancreas also regulates blood sugar by producing insulin.
• The pancreas also creates glucagon that has the opposite effect of insulin and helps maintain blood sugar levels.

7. Stomach

• The stomach receives food from the esophagus and sends it into the small intestine.
• The stomach's role in digestion is to break down food and mix it with digestive enzymes.

8. Small intestine

• The job of the small intestine is to digest food.
• It does this by using chemicals, such as enzymes.
• The small intestine also absorbs nutrients and transfers them to the blood.
• The small intestine is five meters long. The food moves from the small intestine to the large intestine with a series of muscle contractions

9. Large intestine

• The large intestine is located in the abdomen and is 1.5 meters in length.
• The large intestine is involved in digestion. It receives undigested food from the small intestine.
• The large intestine absorbs as much water as possible from the food and then expels the waste and any excess fiber.

10. Lungs

• The lungs are located in the chest and are protected by the rib cage.
• The lungs take in oxygen and expel carbon dioxide. The lungs deliver oxygenated blood to the heart, where it is pumped throughout the body, and they receive deoxygenated blood from the heart after blood travels throughout the body.

Can COVID-19 damage organs?

COVID-19 can cause lasting damage to multiple organs, including the lungs, heart, kidneys, liver, and brain. SARS-CoV-2 first affects the lungs through the nasal passages. When the lungs are severely affected, it can affect the heart. When the heart is affected, the virus disrupts blood vessels, forming clots and eventually blocking the blood supply to the brain. When this occurs, brain damage can lead to death.

The link between these organs is explained by the presence of angiotensin-converting enzyme 2 (ACE2) receptors on the cells of these tissues. SARS-CoV-2 requires ACE2 receptors to bind to cells and enter them. These receptors are present predominantly in the lungs (which is why the lungs are damaged the most), followed by the heart and kidneys.

Once the virus invades the lungs and damages them, it moves to the renal area and heart and causes adverse tissue damage in the respective regions. This leads to multiple organ failures over some time and can cause permanent organ damage or eventual death.

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Organ damage and associated complications due to COVID-19

Lung damage

• Pneumonia: COVID-19 can cause lung complications such as pneumonia and, in the most severe cases, acute respiratory distress syndrome (ARDS). Sepsis may also occur, which is a life-threatening condition in which the body damages its tissues in response to infection. Pneumonia causes inflammation of the lungs and fills them with fluid, causing breathing problems. In some cases, breathing problems may become so serious that they require hospitalization with oxygen therapy or machine monitoring.Although most people recover from pneumonia without any long-term effects, pneumonia caused by COVID-19 can be serious for those with preexisting or coexisting conditions. Damage to the lungs and other related problems can cause breathing issues that take months to resolve, leading to more overall complications.
• ARDS: Following pneumonia, COVID-19 can lead to ARDS, which is a process in which excess fluid gets collected in the lungs and causes blood oxygen levels to fall below normal (hypoxemia). ARDS symptoms are similar to those of COVID-19 and cause damage to the alveoli (air sacs in the lungs) and the capillaries that surround them. In typical COVID-19 cases, the virus attaches to the upper airway near the throat, triggering an immune response and subsequent symptoms.However, in some cases, the virus can go past the upper airway, through the lungs, and into the alveoli, leading to ARDS. ARDS usually appears 8 days after the onset of initial symptoms. Risk factors such as advanced age, diabetes, and high blood pressure increase the likelihood of developing ARDS.

Heart damage

Underlying comorbidities such as hypertension, obesity, and cardiovascular disease have been linked to severe illness with COVID-19, and heart complications, such as myocardial injury, heart failure, and arrhythmias, have been linked to poor survival.

In one recent study, researchers discovered certain cardiac abnormalities and ongoing myocardial inflammation in 60% of patients who recovered from COVID-19. High levels of the blood enzyme troponin (a sign of heart injury) were discovered in 76% of individuals evaluated in the same trial despite the data that their heart function appeared to be preserved. Notably, the majority of the patients in the study did not need to be admitted to the hospital.

Kidney damage

Patients who reported no underlying renal problems before being infected with the coronavirus and some people with severe COVID-19 infections have both shown evidence of kidney impairment and tissue damage. Some data suggests that up to 30% of patients with COVID-19 who were hospitalized in China and New York experienced moderate or severe kidney injury. Signs of kidney damage include proteinuria (excess amounts of protein found in the urine) and abnormal blood components.

Because kidneys have ACE2 receptors, they are subject to attack from the coronavirus. This triggers an immune response that can kill kidney cells. Sometimes, the immune response is violent and causes a cytokine storm, which further damages the organ.

Liver damage

ACE2 receptors are also found in the liver. Increased levels of liver enzymes such as alanine aminotransferase and aspartate aminotransferase have been found in some patients with COVID-19. This is an indication of liver damage. Patients with a history of liver tissue damage (cirrhosis) and those with preexisting liver conditions (chronic liver disease) who are diagnosed with COVID-19 are at high risk of death.

Nervous system damage

There is an increase in the number of patients with COVID-19 who experience neurological symptoms such as brain inflammation, seizures, and hallucinations.

According to a study published in JAMA Neurology by a group of Chinese doctors, more than 33% of 214 patients with COVID-19 who were hospitalized due to severe symptoms in Wuhan had neurologic symptoms, the most common of which were dizziness, headaches, impaired consciousness, loss of taste and smell, and skeletal muscle injuries. Seizures and stroke were more dangerous complications, but these were less commonly reported according to the study.

Frequently asked questions

• What organs are on the left side of the body?The left side of the body houses several vital organs, including the left lung, left kidney, part of the stomach, spleen, and sections of the large and small intestines. Though centrally located, the heart also tilts toward the left side of the chest.
• What is the second largest organ in the human body?The second largest organ in the human body is the liver, which weighs about 1.4 to 1.6 kilograms in adults. It plays a critical role in detoxifying harmful substances, producing bile for digestion, and storing essential nutrients.
• What's the heaviest part of your body?The heaviest part of the human body is the torso, which includes the chest, abdomen, and back. This region houses major organs, such as the heart, lungs, and liver, which collectively contribute to its weight.
• What is the smallest organ in the body? The smallest organ in the human body is the pineal gland, located deep within the brain. It is about the size of a grain of rice, measuring approximately 5 to 8 millimeters in length, and plays a crucial role in regulating circadian rhythms through the secretion of melatonin.

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Organs. Cleveland Clinic. Accessed April 01, 2025. https://my.clevelandclinic.org/health/articles/organs-in-the-body