What are the 78 Organs in the Human Body: Complete List, Functions, Characteristics and Organ Systems

The question ‘What are the 78 organs in the human body?’ is one of the most searched topics in human anatomy. Although many sources mention this number, there is no universally accepted count of exactly 78 organs, as anatomy references differ in how they classify paired organs, glands and other structures.

The number of organs varies because anatomists classify certain structures differently. For example, some count paired organs like the kidneys and lungs separately, while others count them as one organ. Some lists include structures such as the mesentery or endocrine glands individually, while others do not.

This guide provides a complete overview of what are the 78 organs in the human body of the major organs of the human body, their functions and why they are essential for life.

Table of Contents

• What is an Organ
• Why do Some Sources say there are 78 Organs
• 11 Major Organ Systems in the Human Body
• What are the 78 Organs in the Human Body: Complete List
• Largest and Smallest Organs in the Human Body
• How Human Organs Work Together
• Amazing Facts about Human Organs
• Frequently Asked Questions on What are the 78 Organs in the Human Body

What is an Organ

The human body is made up of many specialised structures, each of which is designed to perform a particular task. An organ is a body structure composed of two or more types of tissues that work together to carry out a specific function. 

Although every organ has a unique role, they do not function independently. Instead, they work together as part of organ systems to keep the body functioning smoothly.

Some of the important functions performed by different organs include:

• Supplying oxygen and nutrients to body cells
• Breaking down food and absorbing nutrients
• Removing waste products from the body
• Controlling body activities and responses
• Producing hormones that regulate body functions
• Protecting the body from injury and infection

Together, these organs form an interconnected system that supports growth, survival, and the body's overall balance (homeostasis).

Why do Some Sources say there are 78 Organs

The phrase "78 organs in the human body" is widely searched online, but there is no official anatomical agreement that the human body contains exactly 78 organs.

The total number depends on several factors, including:

• How paired organs are counted (individually or together)
• Treatment of glands as separate organs
• Inclusion of structures such as the skin, mesentery, or placenta
• Differences among medical textbooks and anatomy references.

For this reason, some sources mention 78 organs, while others list 79, 80, or even more than 90.

The most accepted approach in anatomy is to study organs according to the 11 organ systems of the human body.

Also Read: Largest Organ in Human Body

11 Major Organ Systems in the Human Body

Rather than working individually, the organs of the human body are organised into 11 major organ systems. 

Each system consists of a group of organs that perform related functions, helping the body grow, function, and maintain internal balance. 

Organ System	Primary Function
Nervous System	Controls and coordinates body activities
Circulatory System	Transports blood, oxygen, nutrients, and hormones
Respiratory System	Enables breathing and exchanges oxygen and carbon dioxide
Digestive System	Breaks down food and absorbs nutrients
Skeletal System	Provides support, protection, and structure
Muscular System	Enables movement and maintains posture
Endocrine System	Regulates body functions through hormones
Urinary System	Filters blood and removes liquid waste
Reproductive System	Produces reproductive cells and supports reproduction
Lymphatic System	Maintains fluid balance and supports immunity
Integumentary System	Protects the body and helps regulate temperature

Together, these organ systems function as a coordinated network, allowing the human body to perform essential life processes efficiently every day.

What are the 78 Organs in the Human Body: Complete List

If you're wondering what are the 78 organs in the human body, the table below provides a structured overview of the major organs grouped by their respective organ systems. 

This classification makes it easier to understand where each organ belongs and the important function it performs in keeping the body healthy. 

Organ System	Organ	Primary Function
Nervous System	Brain	Controls body activities
	Spinal cord	Transmits nerve impulses
Sensory Organs	Left eye	Vision
	Right eye	Vision
	Left ear	Hearing and balance
	Right ear	Hearing and balance
	Left lacrimal gland	Produces tears
	Right lacrimal gland	Produces tears
Respiratory System	Nose	Smell and air filtration
	Left lung	Gas exchange
	Right lung	Gas exchange
	Pharynx	Passage for food and air
	Larynx	Voice production
	Trachea	Air passage
	Left bronchus	Carries air to the lungs
	Right bronchus	Carries air to the lungs
	Left nasal cavity	Filters inhaled air
	Right nasal cavity	Filters inhaled air
Circulatory System	Heart	Pumps blood throughout the body
Digestive System	Tongue	Taste and swallowing
	Esophagus	Carries food to the stomach
	Stomach	Digests food
	Liver	Processes nutrients and detoxifies the body
	Gallbladder	Stores bile
	Pancreas	Produces digestive enzymes and insulin
	Small intestine	Absorbs nutrients
	Large intestine	Absorbs water
	Rectum	Stores feces
	Anus	Eliminates waste
	Left parotid gland	Produces saliva
	Right parotid gland	Produces saliva
	Left submandibular gland	Produces saliva
	Right submandibular gland	Produces saliva
	Left sublingual gland	Produces saliva
	Right sublingual gland	Produces saliva
	Appendix	Supports gut immunity
	Mesentery†	Supports the intestines
	Omentum†	Cushions and protects abdominal organs
Urinary System	Left kidney	Filters blood
	Right kidney	Filters blood
	Left ureter	Transports urine
	Right ureter	Transports urine
	Urinary bladder	Stores urine
	Urethra	Removes urine from the body
Endocrine System	Left adrenal gland	Produces hormones
	Right adrenal gland	Produces hormones
	Thyroid gland	Regulates metabolism
	Parathyroid gland 1	Regulates calcium levels
	Parathyroid gland 2	Regulates calcium levels
	Parathyroid gland 3	Regulates calcium levels
	Parathyroid gland 4	Regulates calcium levels
	Pituitary gland	Controls other endocrine glands
	Pineal gland	Produces melatonin
Lymphatic System	Spleen	Filters blood
	Thymus	Develops immune cells
	Left tonsil	Immune defence
	Right tonsil	Immune defence
Reproductive System*	Left ovary	Produces eggs
	Right ovary	Produces eggs
	Left fallopian tube	Transports eggs
	Right fallopian tube	Transports eggs
	Uterus	Supports fetal development
	Cervix	Connects the uterus and vagina
	Vagina	Birth canal
	Left testis	Produces sperm
	Right testis	Produces sperm
	Left epididymis	Stores sperm
	Right epididymis	Stores sperm
	Left vas deferens	Transports sperm
	Right vas deferens	Transports sperm
	Prostate gland	Produces seminal fluid
	Penis	Reproduction and urination
	Left mammary gland	Produces milk
	Right mammary gland	Produces milk
	Placenta‡	Nourishes the fetus during pregnancy
Muscular System	Diaphragm	Helps in breathing
Skeletal System	Bone marrow†	Produces blood cells
Integumentary System	Skin	Protects the body and regulates temperature

Important Notes

• *Sex-specific organs are present only in males or females.
• †Some anatomy references classify these as organs, while others do not.
• ‡The placenta is a temporary organ present only during pregnancy.

Largest and Smallest Organs in the Human Body

The organs of the human body vary greatly in size and structure. While some organs are large enough to protect the entire body or perform multiple functions, others are tiny but play an equally important role in regulating essential body processes.

Organ	Interesting Fact
Skin	Largest organ in the human body
Liver	Largest internal organ
Small intestine	Longest organ of the digestive system (about 6 metres in adults)
Pineal gland	One of the smallest organs, responsible for producing melatonin

Also Read: Hormones and Endocrine System

How Human Organs Work Together

Each organ in the human body performs a unique function, but no organ works alone. Instead, organs work together within different organ systems, with the proper functioning of one often depending on the others. 

This constant coordination enables the body to carry out essential life processes efficiently.

For example:

• The lungs absorb oxygen and pass it into the blood.
• The heart pumps this oxygen-rich blood to every part of the body.
• The brain continuously sends signals to regulate breathing, heartbeat, and other vital functions.
• The kidneys filter waste products from the blood and maintain fluid balance.
• The liver processes nutrients, stores energy, and removes toxins from the body.

Together, these organs maintain homeostasis by regulating body temperature, blood pressure, energy production, and other vital functions, ensuring the body remains healthy and functions efficiently.

Amazing Facts about Human Organs

The skin covers about 2 square metres in an average adult. The heart beats nearly 100,000 times every day. The liver can regenerate after losing a significant portion of its tissue. The brain contains approximately 86 billion neurons. Your kidneys filter around 180 litres of fluid daily, although most of it is reabsorbed before urine is formed. The small intestine is about 6 metres long in adults. The stomach expands considerably after a meal. The lungs contain millions of tiny air sacs called alveoli that increase the surface area for gas exchange.

Until now, you have learnt about what are the 78 organs in the human body varies across anatomy references. Understanding the major organs and their functions helps you see how the body's organ systems work together. This knowledge builds a strong foundation for learning human anatomy and health.