Largest and smallest organ in human body

The human body is a marvel of engineering, with thousands of interrelated parts. Some are tiny but still very important. Let’s look at four of the smallest parts of the human body: the smallest muscle, the smallest bone, the smallest organ, and the smallest blood vessel.

What’s the smallest muscle in the human body?

The stapedius, in your middle ear, measures about 1mm in size (or 1/26 of an inch). Connected to the stapes bone, it contracts to pull back the stapes and help protect your inner ear from loud noises. The stapedius also contracts to keep your own voice from sounding too loud in your head.

What’s the smallest bone in the human body?

Conveniently, that would be the stapes. It is one of three tiny bones in the middle ear that convey sound from the outer ear to the inner ear. Collectively called the ossicles, these bones are individually known as the malleus, incus, and stapes. Those are Latin words for the shapes the bones resemble: a hammer, anvil, and stirrup.

What’s the smallest organ in the human body?

You’ll find the pineal gland near the center of the brain, in a groove between the hemispheres. It’s not an organ like those in the abdominal cavity. It’s the human body’s smallest endocrine gland, and it produces melatonin, a hormone (derived from serotonin) that affects how we sleep, wake up, and react to seasonal changes. It’s called pineal because it’s shaped like a little pinecone.

What’s the smallest blood vessel in the human body?

Capillaries, the smallest, thinnest-walled blood vessels in the body, connect veins and arteries. They can be as small as 5-10 micrometers wide — or 50 times thinner than a baby’s hair. Each of us contains about 10 billion of them, with the average adult body containing about 25,000 miles of capillaries.

A human body is mainly composed of 75 to 80 organs, which are collectively called the organ system. These systems function to keep us alive.

An organ can be simply defined as a self-contained group of tissues, which performs a specific function in the body.

The organs are mainly composed of millions of tissues and billions of cells, which remain to unite and work together to carry out a particular function. The different types of organs in the human body are- skin, heart, kidneys, liver, lungs, stomach, brain, etc.

Also Read: Human Body

Based on the weight and the length of the body organ, they are classified as the longest organs in the human body. These organs can be easily seen and are involved in multiple functions.

The ten largest organs in the body are – skin, liver, brain, lungs, heart, kidney, spleen, pancreas, thyroid and joints.

Let us discover interesting information related to the main largest organs in the human body.

The Skin

Skin is the external largest organ of the human body. It is a vital organ with a fleshy surface covered with hair, nerves, glands and nails. It covers your whole body and acts as a barrier between outside and inside environment.

Human skin is approximately two millimetres in thickness, weighs around 10895.10 grams, which makes up about 16 per cent of the overall body mass. Overall, the skin acquires an area of 20 square feet on our body surface.

Functions of the skin

It is one of the primary sense organs that can sense touch, heat, pressure, cold, pain and pleasure. Other functions of the skin are:

• Prevents water loss.
• Regulates body temperature.
• Receives sensory information.
• Stores water, fat, and vitamin D.
• Protects by avoiding the entry of pathogens.
• Synthesizes vitamin D when it is exposed to sunshine.
• Excretes excess of water, salts and other wastes in the form of sweat through the sweat pores.
• Protects the body from environmental factors like UV rays, pollution, germs, radiation from the sun, allergens and more.
• In all higher animals, skin functions as camouflage, which produces colours and patterns that blend in with the surroundings. This helps in both protection from predators and also makes it easier for predators to catch their prey.
• The skin of animals living in a colder region acts as an insulator and protects them from extreme cold conditions.

Also Read: Structure And Functions Of Skin

The Liver

The liver is the largest, internal and diverse metabolically complicated organ in humans. The human liver is involved in 500 different functions. In the human body, the liver is located in the upper right area of the abdomen, beneath the rib cage and the lungs. The liver is a solid organ, which is approximately 3–3.5 pounds or 1493.79 grams.

Functions of the liver

The liver is the only organ, which has the ability to regenerate efficiently. The important functions of the liver are:

• It produces and excretes bile.
• It detoxifies the blood and purifies it.
• It also acts as a blood clotting factor.
• It produces proteins for blood plasma.
• It stores excess glucose in the form of glycogen.
• It filters and eliminates toxins from the blood cells.
• It carries out the metabolism of carbohydrates, fats and proteins.
• It activates enzymes and stores vitamins, minerals and glycogen.
• It synthesizes plasma proteins, namely albumin and clotting factors
• It is responsible to excrete bilirubin, cholesterol, drugs and hormones.

Read More: Liver

Apart from the skin and the liver, there are other organs which are classified as the largest organs, which are typically based on the mass, length, and width of the organ. These organs include:

The Human Brain

The human brain weighs about 3 pounds or 1.36 kilograms, which makes up about 2 per cent of the overall body mass. The approximate size dimensions of the brain are as follows:

Width: 5.5 inches or 14 centimeters

Height: 3.6 inches or 9.3 centimetres

Length (front to back): 6.5 inches or 16.7 centimetres.

Read more: The Human Brain

The Lungs

Based on the storage capacity, lungs are also classified as the largest human organs. The average human lung can hold 4 to 6 litres of air. The total mass of the healthy human lungs is measured to be 1111.67 grams or 2.45 pounds. The total length of the airways running through the two lungs is 1,500 miles or 2,400 kilometres.

Lungs are the major organs of the respiratory system. Humans have a pair of lungs, which are situated within the thoracic cavity of the chest. The right lung is bigger than the left lung. They are soft, spongy and elastic organs enclosed in a thin membranous sac called the pleura. The total size of both the lungs is equal to the size of a tennis court. Therefore, it is called the largest external organ of the human body. 

Also Read: Lung Volumes and Lung Capacity

The Heart

The next biggest organ after the lungs is the heart. The human heart is one of the most important organs responsible for sustaining life. It is about the size of a closed fist or a size as two hands clasped together. The average human heart measure –

4.7 inches or 12 centimetres long

3.3 inches or 8.5 centimetres wide

On average, the human heart pumps around 1.5 million barrels of blood during its lifetime, which is enough to fill about 200 train tank cars.

Also Refer: Interesting facts about the human heart

Frequently Asked Questions on the Largest Organ In The Human Body

This article concludes the introduction to the largest organ in the human body, their features, structure and functions. To know more about the largest organs, other related topics and important questions, keep visiting our website at BYJU’S Biology.