40 Human Body Trivia Questions for Kids
The easiest human body questions in the game, picked for younger players. Every one comes with the answer and a short explanation of why it is right.
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Easy Human Body Questions and Answers
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What is a scab mostly made of?
A dried blood clot
Platelets clump at the break and threads of fibrin knit them into a clot that plugs the wound. Where the clot meets the air it dries and hardens into a scab, and the new skin repairs itself underneath.
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What makes the popping sound when a knuckle is cracked?
A gas bubble forming in the fluid inside the joint
Pulling the joint apart drops the pressure in the synovial fluid and gas comes out of solution as a cavity. Real-time MRI in 2015 caught it appearing at the instant of the pop, and the joint cannot pop again until that gas dissolves back in.
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Knocking your elbow sends an electric jolt down to your little finger. What have you actually hit?
A nerve running close to the surface at the elbow
The ulnar nerve passes through a shallow groove on the inside of the elbow with almost nothing protecting it, so a knock strikes the nerve directly. It serves the little finger and half the ring finger, which is exactly where the jolt is felt.
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What is happening when your ears pop as a plane climbs?
A small tube opens to let air pass behind the eardrum
The Eustachian tube runs from the middle ear to the back of the throat and normally sits closed. Swallowing or yawning flicks it open, air moves through until the pressure matches the cabin, and the eardrum returns to its neutral shape.
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What structure links the calf muscles to the heel bone?
Achilles tendon
The Achilles tendon connects the calf muscles to the heel bone, allowing you to point your foot and push off when walking or running. It is the largest and strongest tendon in the human body.
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About what share of an average adult man's body weight is water?
About 60%
Water makes up roughly 60% of an average adult man's body weight, held in blood, cells and tissues, where it carries nutrients, drives chemical reactions and regulates temperature. The figure is a little lower in adult women, who carry proportionally more fat, and fat holds far less water than muscle.
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How many teeth are in a complete permanent human dentition, including wisdom teeth?
32
A complete adult set has 32 teeth, including four wisdom teeth. Many adults have fewer because wisdom teeth may be removed or never erupt.
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Where are most blood cells produced in a healthy adult?
Red bone marrow
Red bone marrow contains stem cells that generate red blood cells, many white blood cells, and platelet-producing cells. Yellow marrow stores more fat and can become more active in severe demand.
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What is the name of the body's largest artery?
Aorta
The aorta is the body's largest artery, carrying oxygen-rich blood from the heart to the rest of the body. Its elastic walls stretch with each heartbeat and recoil to help maintain steady blood flow.
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Fresh sweat has almost no smell. What creates body odour?
Bacteria on the skin feeding on it and giving off smelly compounds
The glands in the armpits and groin release a thicker secretion than the sweat glands elsewhere, and it is close to odourless when it arrives. Skin bacteria break its fats and proteins down into small volatile molecules, and those are what you smell.
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What transports most oxygen from the lungs through the body?
Red blood cells
Oxygen binds to hemoglobin, an iron-containing protein that fills red blood cells and gives them their color. Mature red blood cells lack a nucleus, leaving more room for hemoglobin, and typically survive about 120 days in circulation.
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What primarily protects the body from infection?
White blood cells
White blood cells primarily protect the body from infection by identifying and attacking harmful pathogens. Some destroy invaders directly, while others coordinate immune defenses or produce antibodies.
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Which blood components gather at damaged vessels to help form clots?
Platelets
Platelets are small cell fragments that stick to damaged vessel walls and help start clot formation. They work with a network of the protein fibrin.
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Which protein in red blood cells binds and transports most of the blood's oxygen?
Hemoglobin
Hemoglobin contains iron-containing heme groups that bind oxygen in the lungs and release it in tissues. It also contributes to the red color of blood.
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What type of blood vessel carries blood away from the heart?
Arteries
Arteries carry blood away from the heart, whether that blood is oxygen-rich or oxygen-poor. Their elastic, muscular walls help withstand and smooth out pressure from each heartbeat.
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Each hair on the body grows out of which structure in the skin?
Follicle
A hair grows from a follicle, a narrow pocket sunk into the skin with a cluster of rapidly dividing cells at its base. A sebaceous gland opens into that same pocket and coats the hair in oil as it pushes out.
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What does BMI stand for?
Body mass index
Body mass index divides weight in kilograms by height in metres squared, giving a rough screening figure rather than a diagnosis.
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How many bones are in the adult human body?
206
An adult skeleton is normally counted at 206 bones. A newborn has around 270: the plates of the skull, the vertebrae of the sacrum and the segments of the tailbone all fuse together during childhood, so the total goes down as the body grows.
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Which brain region coordinates balance and fine movement?
Cerebellum
The cerebellum compares intended movements with sensory feedback and fine-tunes muscle activity. It is important for balance, posture, and precise coordination.
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When you hold your breath, what actually forces you to breathe again?
Carbon dioxide building up in the blood
The body tracks carbon dioxide far more closely than oxygen. Sensors in the brainstem and the arteries respond to the rising level and drive the urge to breathe. Breathing hard beforehand blows carbon dioxide off and delays that urge, which is why it is dangerous to do before swimming underwater.
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What does CPR stand for?
Cardiopulmonary resuscitation
Cardiopulmonary resuscitation combines chest compressions with rescue breaths to keep blood and oxygen moving when the heart has stopped.
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Which organelle is commonly called the powerhouse of the cell?
Mitochondrion
Mitochondria make most of a cell's ATP, the molecule used to power many cellular processes. They have their own small amount of DNA and likely evolved from ancient bacteria.
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How many cervical vertebrae does a typical human have?
7
Humans have seven cervical vertebrae. The usual counts are five lumbar vertebrae, 12 thoracic vertebrae, and 24 movable vertebrae.
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Which organ has two atria and two ventricles?
The heart
The human heart has two atria and two ventricles, making four chambers in all.
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How many chromosomes are in a typical human body cell?
46
A typical human body cell carries 46 chromosomes, arranged as 23 pairs, one of each pair inherited from each parent. Of those pairs, 22 are matching autosomes and the last pair decides sex; sperm and egg cells carry a single set of 23, and a count of 92 turns up only in an abnormal cell that has doubled its whole set.
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Which bone is commonly called the collarbone?
Clavicle
The clavicle is the bone that runs between the breastbone and shoulder blade and is commonly called the collarbone.
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Which retinal cells are chiefly responsible for color vision?
Cones
Cone cells in the retina support color vision and function best in relatively bright light.
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Which clear front part of the eye helps focus incoming light?
Cornea
The cornea is the transparent front surface of the eye and contributes to focusing light.
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Which sense organ is primarily responsible for hearing?
ears
Sound waves vibrate the eardrum, and three tiny bones, the hammer, anvil and stirrup, relay that vibration into the fluid-filled cochlea, where it is converted into nerve signals. The vestibular system inside the same inner ear also helps control balance.
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Which substance forms the hard outer covering of tooth crowns?
Enamel
Enamel protects the visible crown of a tooth from chewing forces and acids. It is highly mineralized and cannot regenerate once it is lost.
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What tube connects the throat to the stomach?
Esophagus
The esophagus is a muscular tube about 25 cm long running from the throat to the stomach. It does not depend on gravity: rings of muscle squeeze shut behind each mouthful in a travelling wave, which is why swallowing works just as well lying down.
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How does sweating cool you down?
Evaporating from the skin carries heat away with it
It is the change from liquid to vapour that takes the heat, so the sweat has to evaporate to do anything at all. Sweat that simply drips off is wasted, which is why humid heat feels far worse than dry heat at the same temperature.
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Which eye structure changes shape to focus light?
Lens
The lens changes shape to focus light onto the retina for clear vision at different distances.
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Which sense organ is primarily responsible for sight?
eyes
The eyes are the organs used for sight.
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How does shivering warm you up?
Fast involuntary muscle contractions give off heat
Muscle is inefficient: most of the energy it uses leaves as heat rather than movement. Shivering works opposing muscles against each other to exploit that, and can lift heat production to several times the resting rate.
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The femur is the major bone of which body region?
Thigh
The femur runs from the hip to the knee and forms the framework of the thigh. It meets the tibia at the knee joint.
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Why do you still feel as though you are turning for a few seconds after you stop spinning?
Fluid in the inner ear keeps moving after you have stopped
The semicircular canals of the inner ear are loops of fluid. When you stop, the fluid's momentum keeps it sliding for a moment and it goes on bending the sensory hairs that report rotation, so the brain is told you are still turning.
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Which organ stores and concentrates bile between meals?
Gallbladder
Bile is made continuously by the liver, and the gallbladder concentrates it by absorbing water so a small sac can hold a useful reserve. Eating fatty food triggers the hormone cholecystokinin, which makes the gallbladder contract and squeeze bile into the small intestine to help digest fats.
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What is the rumbling noise a hungry stomach makes?
Gas and fluid being squeezed along by the gut's muscle contractions
The waves of muscle that push food along keep sweeping through when the gut is empty, and with only gas and liquid to move, the noise carries. The medical name is borborygmi.
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Why can standing up quickly leave you dizzy for a moment?
Gravity pulls blood downward and the pressure feeding the brain briefly drops
Around half a litre of blood drops into the legs the instant you stand. Sensors in the neck and chest detect the fall and tell the heart to speed up and the vessels to tighten, but there is a gap of a few seconds before that takes effect. The name is orthostatic hypotension.
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