An adult human body has 206 bones; 656 to 850 muscles, depending on which expert to consult and 11 major organ systems.

Smallest Muscle: Stapedius

Size: 1.27 mm (0.05 in) long

The stapedius muscle is located in the middle ear. By controlling the stapes, it helps control the amplitude of sound waves from the general external environment to the inner ear.

Most Active Muscle: Eye

The human eye moves about 100,000 times a day. Even when we are aleep or dreaming, the eye muscles are also moving. This is what we call rapid eye movement (REM) sleep.

Strongest Muscle: Jaw

Mascular strength usually refers to the ability to exert effort on an external object. By this definition, the masseter or jaw is the strongest human muscle.

Longest Muscle: Sartorius

The Sartorius muscle, also called the tailor’s muscle is a long thin muscle running from the pelvis and across the frontal thigh to the top of the tibia below the knee. It aids in flexion, abduction and lateral rotation of hip and flexion of the knee. Looking down to see if one has stepped on something is made possible by the Sartorius.

Largest Muscle: Gluteus Maximus

The buttock or gluteus maximus muscle is large and powerful as its job is to keep the trunk of the body in erect posture. It is the main antigravity muscle that aids in walking up stairs.

Hardest Working Muscle: Heart

The human heart beats about 72 times per minute or 100,000 a day; roughly about 2.5 billion times throughout a person’s lifetime. It pumps out 2 oz (71 g) of blood at every heartbeat which translates to about 4,300 gallons (16,277 liter) of blood daily.

The heart pumps oxygen-rich blood throughout the body. Blood contains oxygen and nutrients for every cell in the body to survive. The oxygen-rich blood travels throughout the arteries and vessels, nourishing the body so it can properly function.

Smallest Bone: Stapes (Stirrup)

Size: 3.3 mm (0.13 in)

Together with the malleus (hammer) and incus (anvil), the stapes or stirrup bone, increase and transfer sound vibrations from the eardrum to the sensitive hair cells in the inner ear.

Longest and Largest Bone: Femur

Average size: 480 mm (19 in) long; 23 mm (0.92 in) diameter

Out of the 206 bones in the adult human body, the femur or thighbone is the longest and the largest. It forms part of the hip and part of the knee and is capable of supporting up to 30 times the weight of an adult. The word femur means “thigh” in Latin.

Largest Internal Organ; Heaviest Organ: Liver

Average size: 1.6 kg (3.5 lbs)      

Average Weight: 228 mm (9 in) long, 101 mm (4 in) wide

Located behind the right lower ribs, the liver performs up to 100 bodily functions. It does the most important work in the body and is more complex than the heart or lung. These functions are what make us “live”, hence the name “liver.”

Largest Organ: Skin

The average human adult has a skin surface area between 1.5-2.0 sq m (16.1-21.5 sq ft), most of it between 2-3 mm (0.10 in) thick.  The skin’s important function includes: protection, sensation, heat regulation, evaporation control, excretion and absorption.

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