The human body is an extraordinary machine, but its secrets are often misunderstood. Bones, organs, records and biology facts that will catch you off guard.
Bones, organs, muscles and blood... This anatomy quiz will probably surprise you, even if you think you already know the answers.
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The human body is one of the most complex structures in existence. Yet plenty of misconceptions about how it works keep circulating. Did you know you have far more bones at birth than in adulthood? Or that the liver is the heaviest internal organ, not the brain? Human biology is full of unexpected details.
This quiz covers bones, organs, muscles, blood circulation and a few little-known anatomical records. Perfect for curious minds, health students or anyone who wants to understand their own body a little better.
All ten easy level questions, with the answer and the reasoning behind it.
Correct answer: The kidneys
The kidneys, two of them, each about the size of a fist.
Correct answer: The heart and lungs
The heart and lungs, within the ribcage.
Correct answer: 20
Twenty, which are later replaced by up to 32 adult teeth.
Correct answer: A nerve
A nerve, the ulnar nerve, running close to the skin at the elbow.
Correct answer: The diaphragm
The diaphragm, the main muscle used for breathing.
Correct answer: The iris
The iris, which controls the size of the pupil at its centre.
Correct answer: Your nose
Your nose, which also does a large part of the work when you taste food.
Correct answer: The neck
The neck, held up by seven vertebrae, the same number as a giraffe's.
Correct answer: Sweat
Sweat, which cools you as it evaporates.
Correct answer: The bladder
The bladder. The gall bladder stores bile instead.
Want to warm up before playing or double-check something? Open any question to reveal the correct answer and a short explanation.
Correct answer: 206
A healthy adult has 206 bones. At birth, a baby has around 300. As the body grows, many bones gradually fuse together to form a single bone. This fusion process is typically complete by around age 25.
Correct answer: The skin
The skin is the largest organ in the human body. In an adult, it covers around 2 square metres and weighs between 3 and 4 kg. It acts as a protective barrier, regulates body temperature and provides sensory detection.
Correct answer: The pancreas
Insulin is produced by the pancreas, specifically by the beta cells in the islets of Langerhans. It regulates blood sugar levels. When these cells stop functioning correctly, the result is diabetes.
Correct answer: The femur
The femur is the longest and strongest bone in the human body. It connects the hip to the knee and accounts for roughly 26% of a person's height. It is also the hardest bone to break, although a femur fracture is extremely serious.
Correct answer: 7,500 litres
The heart pumps an average of 7,500 litres of blood per day, roughly 5 litres per minute at rest. Over a lifetime, that adds up to more than 200 million litres. It beats around 100,000 times a day without ever stopping.
Correct answer: 8
The tongue is made up of 8 distinct muscles, divided into two groups: intrinsic muscles (which change its shape) and extrinsic muscles (which control its position). It is one of the most agile organs in the human body.
Correct answer: The liver
The liver is the heaviest internal organ, weighing between 1.2 and 1.5 kg. It performs over 500 functions: filtering blood, producing bile, storing glucose, synthesising proteins and eliminating toxins.
Correct answer: 60 seconds
Red blood cells complete one full circuit of the body in about 60 seconds at rest. During exercise, this can be three times faster. The body contains around 25 trillion red blood cells, and each one lives for approximately 120 days.
Correct answer: The nose and ears
The nose and ears get longer with age: their cartilage slackens under gravity and the skin loses its elasticity. It is not real growth, unlike nails and hair, which grow all your life.
Correct answer: The stapes (stirrup)
The stapes, or stirrup, sits in the middle ear and measures about 3 mm. With the malleus and the incus, it carries vibrations from the eardrum to the inner ear.
Stuck on one, or just curious how nasty it gets? Every hard mode question is here with its answer and the reasoning behind it.
Correct answer: Red blood cells
Red blood cells, which lose their nucleus to make more room for haemoglobin.
Correct answer: The islets of Langerhans
The islets of Langerhans, named after the German who described them in 1869.
Correct answer: The aorta
The aorta, which leaves the left ventricle at around 2.5 centimetres across.
Correct answer: Your mother
Your mother, which lets scientists trace maternal lines far back in time.
Correct answer: The hyoid
The hyoid, in the neck, held in place by muscles and ligaments.
Correct answer: Broca's area
Broca's area, named after the French doctor Paul Broca, who studied it in 1861.
Correct answer: The gluteus maximus
The gluteus maximus, which you are probably sitting on.
Correct answer: The Eustachian tube
The Eustachian tube, which is why swallowing helps your ears on a plane.
Correct answer: The coronary arteries
The coronary arteries, whose blockage causes a heart attack.
Correct answer: The scapula
The scapula. The clavicle is the collarbone, and the humerus the upper arm bone.