[{"id":"heart","name":"Heart","aliases":[],"attributes":{"system":"Cardiovascular","region":"Chest","kind":"Organ","count":1,"size":12},"clues":{"description":["A fist-sized organ sitting in the middle of your chest, tilted slightly to the left.","Inside it has four hollow chambers separated by walls and one-way valves.","Its walls are thick muscle, and it sits snugly between the two lungs."],"function":["It never takes a break, working every second of your life.","It squeezes about 60 to 100 times a minute when you are resting.","It pumps blood around the body, sending it out through the aorta."]}},{"id":"lungs","name":"Lungs","aliases":["Lung"],"attributes":{"system":"Respiratory","region":"Chest","kind":"Organ","count":2,"size":25},"clues":{"description":["A spongy, pinkish pair that fills most of your chest.","They are protected by the rib cage and rest on the diaphragm.","The left one is a little smaller to make room for the heart."],"function":["They change size all day long, growing and shrinking.","Every breath you take fills them with air.","They pass oxygen into the blood and let carbon dioxide out."]}},{"id":"liver","name":"Liver","aliases":[],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":21},"clues":{"description":["The heaviest internal organ, reddish-brown and wedge-shaped.","It sits in the upper right of the belly, tucked under the ribs.","The small green gallbladder hangs underneath it."],"function":["It does hundreds of chemical jobs and can regrow lost parts.","It filters the blood and breaks down alcohol and many medicines.","It makes bile, which helps you digest fat."]}},{"id":"kidney","name":"Kidney","aliases":["Kidneys"],"attributes":{"system":"Urinary","region":"Abdomen","kind":"Organ","count":2,"size":11},"clues":{"description":["A bean-shaped pair, each about the size of a computer mouse.","They sit against the back wall of the belly, just below the ribs.","Each one wears a small hormone gland on top like a little hat."],"function":["They clean the blood around the clock.","They balance the body's water and salt levels.","They turn waste from the blood into urine."]}},{"id":"pancreas","name":"Pancreas","aliases":[],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":15},"clues":{"description":["A long, soft, leaf-shaped organ hidden behind the stomach.","Its wide 'head' sits in the curve of the first part of the small intestine.","It is both a digestive organ and a hormone gland at the same time."],"function":["It releases strong juices into the gut to break down food.","It helps keep your blood sugar steady.","Its islet cells make insulin; when they fail, diabetes can follow."]}},{"id":"spleen","name":"Spleen","aliases":[],"attributes":{"system":"Immune & lymphatic","region":"Abdomen","kind":"Organ","count":1,"size":12},"clues":{"description":["A soft, purple organ about the size of a fist.","It hides in the upper left of the belly, behind the stomach.","It sits under the lower left ribs and can rupture in a hard hit."],"function":["You can live without it, but it is still useful.","It filters the blood and removes old, worn-out red blood cells.","It stores white blood cells and helps fight some infections."]}},{"id":"gallbladder","name":"Gallbladder","aliases":["Gall bladder"],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":8},"clues":{"description":["A small, pear-shaped greenish sac.","It sits tucked under the liver in the upper right belly.","Hard little stones sometimes form inside it."],"function":["It is a storage tank rather than a factory.","It concentrates a yellow-green digestive fluid.","It squeezes bile into the gut after a fatty meal."]}},{"id":"stomach","name":"Stomach","aliases":[],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":25},"clues":{"description":["A stretchy, J-shaped bag in the upper left belly.","Its inner lining is folded into ridges that flatten out when it is full.","It sits between the food pipe and the small intestine."],"function":["It can growl when it is empty.","It churns food into a thick mush.","It holds strong acid and enzymes that start digesting protein."]}},{"id":"small-intestine","name":"Small intestine","aliases":["Small bowel"],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":600},"clues":{"description":["Despite its name, it is the longest part of the digestive tract.","A narrow tube coiled up in the middle of the belly.","It has three parts: the duodenum, the jejunum and the ileum."],"function":["Most of the work on your food happens here.","Its lining is covered in tiny finger-like villi.","It absorbs most of the nutrients from digested food into the blood."]}},{"id":"large-intestine","name":"Large intestine","aliases":["Colon","Large bowel"],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":150},"clues":{"description":["A wide tube that frames the belly like a picture frame.","It starts at the lower right, near the appendix.","It is shorter than the tube before it but much wider."],"function":["It is home to trillions of friendly bacteria.","It soaks up water from what is left of your food.","It forms waste into stool before it leaves the body."]}},{"id":"appendix","name":"Appendix","aliases":[],"attributes":{"system":"Digestive","region":"Abdomen","kind":"Organ","count":1,"size":9},"clues":{"description":["A small, worm-shaped pouch with a dead end.","It hangs off the first part of the large intestine.","It is in the lower right belly, where sudden pain may mean surgery."],"function":["For a long time people thought it did nothing at all.","It contains immune tissue.","It may store good gut bacteria to restock the gut after illness."]}},{"id":"urinary-bladder","name":"Bladder","aliases":["Urinary bladder"],"attributes":{"system":"Urinary","region":"Pelvis","kind":"Organ","count":1,"size":10},"clues":{"description":["A hollow, stretchy, muscular bag.","It sits low in the pelvis, just behind the pubic bone.","Two thin tubes from the kidneys empty into it."],"function":["It is a storage tank you can feel filling up.","Its wall stretches as it fills and squeezes when it empties.","It holds urine until you go to the toilet."]}},{"id":"brain","name":"Brain","aliases":[],"attributes":{"system":"Nervous","region":"Head","kind":"Organ","count":1,"size":17},"clues":{"description":["A soft, wrinkly organ that weighs about 1.4 kg.","It floats in fluid inside the skull.","It has two halves called hemispheres, joined by a thick bridge of fibres."],"function":["It uses about a fifth of the body's energy.","It controls movement, senses, memory and feelings.","Billions of neurons inside it send electrical signals to each other."]}},{"id":"cerebellum","name":"Cerebellum","aliases":[],"attributes":{"system":"Nervous","region":"Head","kind":"Organ","count":1,"size":10},"clues":{"description":["A wrinkled, ball-shaped structure at the back of the head.","Its name means 'little brain' in Latin.","It sits beneath the big hemispheres, just behind the brainstem."],"function":["You use it every time you ride a bike.","It fine-tunes your movements so they are smooth and accurate.","It controls balance and coordination; alcohol makes it work badly."]}},{"id":"spinal-cord","name":"Spinal cord","aliases":[],"attributes":{"system":"Nervous","region":"Back","kind":"Organ","count":1,"size":45},"clues":{"description":["A long, soft cable about as thick as a finger.","It runs down the back, protected inside a tunnel of bones.","It starts at the base of the brain and ends around the waist."],"function":["It is the body's main information highway.","It carries messages between the brain and the rest of the body.","It also handles quick reflexes, like pulling your hand off a hot stove."]}},{"id":"skin","name":"Skin","aliases":[],"attributes":{"system":"Integumentary","region":"Whole body","kind":"Organ","count":1,"size":null},"clues":{"description":["The largest organ in the body.","It covers you from head to toe.","It has three layers; the outer one sheds dead cells all the time."],"function":["It is a waterproof barrier between you and the world.","It helps control body temperature by sweating.","It feels touch, heat and pain, and makes vitamin D in sunlight."]}},{"id":"esophagus","name":"Esophagus","aliases":["Oesophagus","Food pipe","Gullet"],"attributes":{"system":"Digestive","region":"Chest","kind":"Organ","count":1,"size":25},"clues":{"description":["A muscular tube about 25 cm long.","It runs down through the chest, behind the windpipe.","It connects the throat to the stomach."],"function":["You use it every time you swallow.","It pushes food down with waves of muscle squeezes.","Its lower ring of muscle keeps stomach acid from coming back up."]}},{"id":"trachea","name":"Trachea","aliases":["Windpipe"],"attributes":{"system":"Respiratory","region":"Neck","kind":"Organ","count":1,"size":11},"clues":{"description":["A tube about 11 cm long, in the front of the neck.","It is held open by C-shaped rings of cartilage.","It runs from the voice box down into the chest."],"function":["Air passes through it with every breath.","Its lining has tiny hairs that sweep mucus and dust upward.","It splits into two branches that lead to the lungs."]}},{"id":"larynx","name":"Larynx","aliases":["Voice box","Adam's apple"],"attributes":{"system":"Respiratory","region":"Neck","kind":"Organ","count":1,"size":5},"clues":{"description":["A box of cartilage at the front of the neck.","It sits at the top of the windpipe.","It forms a bump in the throat that is often bigger in men."],"function":["You use it whenever you talk or sing.","It holds the vocal cords.","It also guards the airway and helps you cough."]}},{"id":"vocal-cords","name":"Vocal cords","aliases":["Vocal folds","Vocal cord"],"attributes":{"system":"Respiratory","region":"Neck","kind":"Other","count":2,"size":1.8},"clues":{"description":["Two small folds of tissue shaped like a V.","They stretch across the inside of the voice box.","Seen from above with a camera, they open and close like curtains."],"function":["They vibrate hundreds of times per second.","Tightening them makes your voice higher.","They turn air from the lungs into the sound of speech."]}},{"id":"epiglottis","name":"Epiglottis","aliases":[],"attributes":{"system":"Respiratory","region":"Neck","kind":"Other","count":1,"size":3},"clues":{"description":["A small, leaf-shaped flap made of flexible cartilage.","It sits at the back of the tongue, above the voice box.","It points upward when you breathe and folds down when you eat."],"function":["It works like a trapdoor.","It stops food from going down the wrong way.","It covers the windpipe each time you swallow."]}},{"id":"bronchi","name":"Bronchi","aliases":["Bronchus"],"attributes":{"system":"Respiratory","region":"Chest","kind":"Other","count":2,"size":5},"clues":{"description":["Two tubes that form an upside-down Y with the windpipe.","They keep splitting into smaller and smaller branches, like a tree.","They have cartilage rings, and the right one is wider and steeper."],"function":["They are part of the air delivery network.","When they get inflamed, you may cough a lot.","They carry air from the windpipe into each lung."]}},{"id":"alveoli","name":"Alveoli","aliases":["Air sacs","Alveolus"],"attributes":{"system":"Respiratory","region":"Chest","kind":"Other","count":480000000,"size":0.02},"clues":{"description":["Hundreds of millions of tiny, balloon-like bubbles.","They sit at the very ends of the smallest airways.","Each has a wall only one cell thick, wrapped in tiny blood vessels."],"function":["Spread flat, they would cover about half a tennis court.","This is where the real gas swap happens.","Oxygen passes from them into the blood; carbon dioxide goes the other way."]}},{"id":"diaphragm","name":"Diaphragm","aliases":[],"attributes":{"system":"Respiratory","region":"Chest","kind":"Muscle","count":1,"size":30},"clues":{"description":["A dome-shaped sheet of muscle.","It stretches across the body like a floor under the lungs.","It separates the chest from the belly."],"function":["You use it about 20,000 times a day without thinking.","It flattens to pull air into the lungs.","Sudden spasms of it give you hiccups."]}},{"id":"thyroid","name":"Thyroid gland","aliases":["Thyroid"],"attributes":{"system":"Endocrine","region":"Neck","kind":"Gland","count":1,"size":5},"clues":{"description":["A small gland shaped like a butterfly.","It sits at the front of the neck.","Its two wings wrap around the windpipe, just below the voice box."],"function":["It sets the body's speed.","Its hormones control how fast you burn energy.","It needs iodine; without enough, it can swell into a goitre."]}},{"id":"adrenal-glands","name":"Adrenal glands","aliases":["Adrenal gland","Suprarenal glands"],"attributes":{"system":"Endocrine","region":"Abdomen","kind":"Gland","count":2,"size":5},"clues":{"description":["A pair of small, triangle-shaped glands.","They sit deep in the back of the belly.","Each one sits on top of a kidney, like a hat."],"function":["They help you deal with stress.","They make cortisol, which helps control blood sugar and stress.","They release a rush of hormone that powers 'fight or flight'."]}},{"id":"pituitary-gland","name":"Pituitary gland","aliases":["Pituitary","Hypophysis"],"attributes":{"system":"Endocrine","region":"Head","kind":"Gland","count":1,"size":1},"clues":{"description":["A tiny gland about the size of a pea.","It hangs from the bottom of the brain on a thin stalk.","It sits in a little bony saddle in the middle of the skull base."],"function":["It is often called the 'master gland'.","It sends hormones that tell other glands what to do.","It makes growth hormone, which controls how tall you grow."]}},{"id":"pineal-gland","name":"Pineal gland","aliases":["Pineal body"],"attributes":{"system":"Endocrine","region":"Head","kind":"Gland","count":1,"size":0.8},"clues":{"description":["A tiny gland shaped like a pine cone.","It sits deep in the middle of the brain.","The philosopher Descartes called it the seat of the soul."],"function":["It is connected to your daily rhythm.","It responds to light and darkness.","It releases melatonin, which makes you sleepy at night."]}},{"id":"thymus","name":"Thymus","aliases":[],"attributes":{"system":"Immune & lymphatic","region":"Chest","kind":"Gland","count":1,"size":5},"clues":{"description":["A soft, two-lobed organ in the upper chest.","It sits behind the breastbone, in front of the heart.","It is biggest during childhood and slowly turns into fat in adults."],"function":["It is a training school.","It teaches young immune cells to tell friend from foe.","T cells are named after it because they mature inside it."]}},{"id":"tonsils","name":"Tonsils","aliases":["Tonsil"],"attributes":{"system":"Immune & lymphatic","region":"Neck","kind":"Gland","count":2,"size":2.5},"clues":{"description":["Two small, oval lumps of soft tissue.","They sit at the back of the throat, one on each side.","You can see them when you open wide and say 'aah'."],"function":["They are an early guard post.","They catch germs that come in through the mouth and nose.","When they get infected and swollen, doctors sometimes remove them."]}},{"id":"lymph-nodes","name":"Lymph nodes","aliases":["Lymph glands","Lymph node"],"attributes":{"system":"Immune & lymphatic","region":"Whole body","kind":"Other","count":600,"size":1},"clues":{"description":["Hundreds of small, bean-shaped lumps spread around the body.","Many are clustered in the neck, armpits and groin.","They are linked by thin vessels carrying a clear fluid."],"function":["They swell up when you are sick.","They filter fluid that drains from the tissues.","They trap germs and are where immune cells gather to fight them."]}},{"id":"salivary-glands","name":"Salivary glands","aliases":["Salivary gland"],"attributes":{"system":"Digestive","region":"Head","kind":"Gland","count":6,"size":5},"clues":{"description":["Three main pairs of glands around the mouth and jaw.","The biggest pair sits just in front of each ear.","Those biggest ones swell up when you have mumps."],"function":["They start working before food even reaches your mouth.","Smelling food can switch them on.","They make about a litre of spit a day to moisten food."]}},{"id":"ureters","name":"Ureters","aliases":["Ureter"],"attributes":{"system":"Urinary","region":"Abdomen","kind":"Other","count":2,"size":27},"clues":{"description":["Two thin, muscular tubes about 25 to 30 cm long.","They run down the back of the belly into the pelvis.","They connect the kidneys to the bladder."],"function":["They are a one-way delivery route.","Waves of muscle push fluid along them, even when you lie down.","They carry urine from each kidney down to the bladder."]}},{"id":"ovaries","name":"Ovaries","aliases":["Ovary"],"attributes":{"system":"Reproductive","region":"Pelvis","kind":"Organ","count":2,"size":3.5},"clues":{"description":["Two almond-sized organs found in females.","They sit low in the pelvis, one on each side.","Each one is close to the end of a thin tube that leads to the womb."],"function":["They are both a gland and a store.","They make the hormones oestrogen and progesterone.","They hold egg cells and usually release one each month."]}},{"id":"uterus","name":"Uterus","aliases":["Womb"],"attributes":{"system":"Reproductive","region":"Pelvis","kind":"Organ","count":1,"size":7.5},"clues":{"description":["A hollow, muscular organ shaped like an upside-down pear, found in females.","It sits in the pelvis, between the bladder and the rectum.","Its lower narrow part is called the cervix."],"function":["It can grow many times its normal size.","Its lining builds up and sheds in a monthly cycle.","It holds and protects a baby as it grows during pregnancy."]}},{"id":"testes","name":"Testes","aliases":["Testicles","Testis"],"attributes":{"system":"Reproductive","region":"Pelvis","kind":"Organ","count":2,"size":4.5},"clues":{"description":["Two oval organs found in males.","They hang outside the belly in a pouch of skin.","They sit outside because they work best a little cooler than the body."],"function":["They are both a gland and a factory.","They make the main male sex hormone.","They produce sperm cells."]}},{"id":"skull","name":"Skull","aliases":["Cranium"],"attributes":{"system":"Skeletal","region":"Head","kind":"Bone","count":1,"size":20},"clues":{"description":["A rounded bony case made of 22 bones.","Most of its bones are locked together by wavy seams.","It has two large eye sockets and a hole at the bottom for the spinal cord."],"function":["It is the body's helmet.","It protects the brain.","It also shapes the face and holds the teeth and eyes in place."]}},{"id":"mandible","name":"Mandible","aliases":["Jawbone","Lower jaw"],"attributes":{"system":"Skeletal","region":"Head","kind":"Bone","count":1,"size":10},"clues":{"description":["A U-shaped bone at the bottom of the face.","It is the only bone in the head that can move freely.","It is the strongest bone of the face and holds the lower teeth."],"function":["You use it every time you speak.","Powerful muscles pull it up and down.","It moves to bite and chew food."]}},{"id":"clavicle","name":"Clavicle","aliases":["Collarbone","Collar bone"],"attributes":{"system":"Skeletal","region":"Chest","kind":"Bone","count":2,"size":15},"clues":{"description":["A long, thin, S-shaped bone.","It lies flat across the top of the chest, easy to feel under the skin.","It runs from the breastbone out to the shoulder blade."],"function":["It is a strut that holds the arm away from the body.","It passes force from the arm to the rest of the skeleton.","It is one of the most often broken bones, usually from falling on an arm."]}},{"id":"scapula","name":"Scapula","aliases":["Shoulder blade"],"attributes":{"system":"Skeletal","region":"Back","kind":"Bone","count":2,"size":16},"clues":{"description":["A flat, triangle-shaped bone.","It lies on the upper back, over the ribs.","It has a shallow socket that holds the top of the upper arm bone."],"function":["It is a moving base for the arm.","Many shoulder and back muscles attach to it.","It slides and tilts to let you raise your arm above your head."]}},{"id":"sternum","name":"Sternum","aliases":["Breastbone","Breast bone"],"attributes":{"system":"Skeletal","region":"Chest","kind":"Bone","count":1,"size":17},"clues":{"description":["A flat bone shaped a bit like a necktie or a short sword.","It sits in the middle of the chest, easy to feel.","Many of the ribs connect to it through cartilage."],"function":["It is part of a protective cage.","It shields the heart and the big blood vessels.","During CPR, people press hard on it to pump the heart."]}},{"id":"ribs","name":"Ribs","aliases":["Rib","Rib cage"],"attributes":{"system":"Skeletal","region":"Chest","kind":"Bone","count":24,"size":24},"clues":{"description":["Twelve pairs of long, curved bones.","They wrap around the chest from the spine toward the front.","The lowest two pairs are 'floating' and do not reach the front."],"function":["Together they form a cage.","They protect the heart and lungs.","They move up and out each time you breathe in."]}},{"id":"vertebrae","name":"Vertebrae","aliases":["Vertebra","Spine","Backbone","Spinal column"],"attributes":{"system":"Skeletal","region":"Back","kind":"Bone","count":33,"size":4},"clues":{"description":["A stack of 33 small, ring-shaped bones.","They run down the middle of the back, from the skull to the tailbone.","Soft cushions sit between most of them."],"function":["Together they are a flexible column.","They let you bend and twist while holding your body upright.","Their hollow centres protect the body's main nerve cable."]}},{"id":"intervertebral-discs","name":"Intervertebral discs","aliases":["Spinal discs","Disc","Discs"],"attributes":{"system":"Skeletal","region":"Back","kind":"Connective tissue","count":23,"size":4},"clues":{"description":["Round, flat cushions with a jelly-like centre.","They are stacked between the bones of the back.","Each has a tough outer ring around a soft core."],"function":["They are shock absorbers.","They let the back bend while spreading out weight.","When one bulges out of place, it is often called 'slipped'."]}},{"id":"humerus","name":"Humerus","aliases":["Upper arm bone"],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Bone","count":2,"size":33},"clues":{"description":["A long bone in the upper limb.","It runs from the shoulder to the elbow.","Its rounded top fits into a shallow socket on the shoulder blade."],"function":["It is a lever for lifting.","The biceps and triceps attach near it to move the arm.","Bumping a nerve near its lower end gives the 'funny bone' tingle."]}},{"id":"radius","name":"Radius","aliases":[],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Bone","count":2,"size":24},"clues":{"description":["One of two long bones in the forearm.","It is on the thumb side of the forearm.","Its wide lower end is a very common site for a broken wrist."],"function":["It helps you turn your hand over.","It rotates around its partner bone when you twist a doorknob.","It carries most of the force from the hand to the elbow."]}},{"id":"ulna","name":"Ulna","aliases":[],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Bone","count":2,"size":26},"clues":{"description":["One of two long bones in the forearm.","It is on the little-finger side of the forearm.","Its hooked top end forms the point of the elbow."],"function":["It is a stable base for the forearm.","It forms a hinge with the upper arm bone.","It stays mostly still while its partner bone rotates around it."]}},{"id":"femur","name":"Femur","aliases":["Thigh bone","Thighbone"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Bone","count":2,"size":48},"clues":{"description":["The longest and strongest bone in the body.","It runs from the hip to the knee.","Its rounded head fits into a deep socket in the pelvis."],"function":["It carries much of your weight.","Big muscles attach to it to power walking and running.","Its hollow centre holds marrow that makes blood cells."]}},{"id":"patella","name":"Patella","aliases":["Kneecap","Knee cap"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Bone","count":2,"size":5},"clues":{"description":["A small, flat, triangle-shaped bone.","It sits at the front of the leg, where it bends.","It is set inside a tendon and slides in a groove at the end of the thigh bone."],"function":["It is a shield for a joint.","It works like a pulley for the big thigh muscle.","It makes kicking and straightening the leg stronger."]}},{"id":"tibia","name":"Tibia","aliases":["Shinbone","Shin bone"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Bone","count":2,"size":38},"clues":{"description":["A long, thick bone in the lower leg.","Its sharp front edge is right under the skin, easy to bump.","It is on the inner side of the lower leg, next to a thinner partner bone."],"function":["It is a weight-bearing pillar.","It carries almost all the body's weight between knee and ankle.","Its lower end forms the bump on the inside of your ankle."]}},{"id":"fibula","name":"Fibula","aliases":["Calf bone"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Bone","count":2,"size":37},"clues":{"description":["A long, very thin bone in the lower leg.","It runs along the outer side of the lower leg.","Its lower end forms the bump on the outside of your ankle."],"function":["It carries very little body weight.","Many leg muscles attach along it.","Surgeons sometimes take a piece of it to rebuild other bones."]}},{"id":"pelvis","name":"Pelvis","aliases":["Hip bones","Pelvic girdle"],"attributes":{"system":"Skeletal","region":"Pelvis","kind":"Bone","count":1,"size":28},"clues":{"description":["A large, bowl-shaped ring of bones.","It sits at the base of the spine and links the trunk to the legs.","Its shape is usually wider and rounder in women than in men."],"function":["It is the body's foundation.","It carries the weight of the upper body to the legs.","It protects the bladder and other organs in the lower belly."]}},{"id":"sacrum","name":"Sacrum","aliases":[],"attributes":{"system":"Skeletal","region":"Pelvis","kind":"Bone","count":1,"size":11},"clues":{"description":["A triangle-shaped bone at the bottom of the back.","It is made of five bones that fuse together in adulthood.","It is wedged between the two hip bones."],"function":["It connects the spine to the hips.","It passes the upper body's weight down to the legs.","Its name comes from the Latin for 'holy bone'."]}},{"id":"coccyx","name":"Coccyx","aliases":["Tailbone","Tail bone"],"attributes":{"system":"Skeletal","region":"Pelvis","kind":"Bone","count":1,"size":3},"clues":{"description":["A tiny, triangle-shaped bone at the very bottom of the back.","It is made of three to five little bones fused together.","It is what remains of a rear appendage our distant ancestors had."],"function":["It can hurt a lot if you fall hard on your bottom.","Several muscles and ligaments anchor to it.","It helps support you when you sit leaning back."]}},{"id":"calcaneus","name":"Calcaneus","aliases":["Heel bone","Heel"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Bone","count":2,"size":8},"clues":{"description":["The largest bone in the foot.","It sits at the very back of the foot.","A thick tendon from the calf attaches to its back."],"function":["It takes a hit with every step.","It is the first part of the foot to strike the ground when you walk.","It works as a lever so the calf can lift you onto your toes."]}},{"id":"stapes","name":"Stapes","aliases":["Stirrup"],"attributes":{"system":"Skeletal","region":"Head","kind":"Bone","count":2,"size":0.3},"clues":{"description":["The smallest bone in the human body.","It is shaped like the foot loop that hangs from a horse's saddle.","It sits deep in the middle ear, the last of three tiny bones."],"function":["It is part of a sound relay team.","It passes vibrations from the eardrum deeper into the ear.","It pushes on a small window into the fluid-filled inner ear."]}},{"id":"biceps","name":"Biceps","aliases":["Bicep","Biceps brachii"],"attributes":{"system":"Muscular","region":"Arm & hand","kind":"Muscle","count":2,"size":30},"clues":{"description":["A muscle with two heads.","It sits on the front of the upper arm.","It bulges up when people 'make a muscle'."],"function":["It is a favourite of gym-goers.","It bends the elbow.","It also turns the palm to face up, like turning a screwdriver."]}},{"id":"triceps","name":"Triceps","aliases":["Tricep","Triceps brachii"],"attributes":{"system":"Muscular","region":"Arm & hand","kind":"Muscle","count":2,"size":30},"clues":{"description":["A muscle with three heads.","It covers the back of the upper arm.","It makes up about two thirds of the bulk of the upper arm."],"function":["It works opposite to the muscle on the front of the arm.","It straightens the elbow.","It does most of the work in a push-up."]}},{"id":"deltoid","name":"Deltoid","aliases":["Delts","Deltoid muscle"],"attributes":{"system":"Muscular","region":"Arm & hand","kind":"Muscle","count":2,"size":15},"clues":{"description":["A thick, triangle-shaped muscle.","It forms the rounded cap of the shoulder.","It is named after a triangle-shaped Greek letter."],"function":["It is a common spot for vaccine injections.","It lifts the arm out to the side.","Its front and back parts swing the arm forward and back."]}},{"id":"pectoralis-major","name":"Pectoralis major","aliases":["Pecs","Chest muscle","Pectorals"],"attributes":{"system":"Muscular","region":"Chest","kind":"Muscle","count":2,"size":20},"clues":{"description":["A big, fan-shaped muscle.","It covers the upper front of the chest.","It runs from the breastbone and collarbone to the upper arm bone."],"function":["It is the main target of the bench press.","It pulls the arm across the body.","It helps with pushing and hugging movements."]}},{"id":"rectus-abdominis","name":"Rectus abdominis","aliases":["Abs","Six-pack","Abdominal muscles"],"attributes":{"system":"Muscular","region":"Abdomen","kind":"Muscle","count":2,"size":30},"clues":{"description":["A long, flat pair of muscles.","They run up the front of the belly, from the pelvis to the ribs.","Bands of tendon cross them, which can give a blocky, chiselled look."],"function":["They are worked in sit-ups and crunches.","They bend the trunk forward.","They tighten the belly to help you cough, push and stay upright."]}},{"id":"trapezius","name":"Trapezius","aliases":["Traps"],"attributes":{"system":"Muscular","region":"Back","kind":"Muscle","count":2,"size":35},"clues":{"description":["A large, flat, diamond-shaped muscle.","It covers the upper back and the back of the neck.","Its name comes from its four-sided shape."],"function":["It is a common place to feel tension and knots.","It shrugs the shoulders upward.","It moves and steadies the shoulder blades."]}},{"id":"latissimus-dorsi","name":"Latissimus dorsi","aliases":["Lats"],"attributes":{"system":"Muscular","region":"Back","kind":"Muscle","count":2,"size":35},"clues":{"description":["The broadest muscle of the back.","It wraps from the lower back up to the upper arm.","When well-trained, it gives the back a V shape."],"function":["It is used in pull-ups and swimming.","It pulls the arm down and back toward the body.","It helps with climbing and rowing movements."]}},{"id":"gluteus-maximus","name":"Gluteus maximus","aliases":["Glutes","Buttock muscle"],"attributes":{"system":"Muscular","region":"Pelvis","kind":"Muscle","count":2,"size":25},"clues":{"description":["The largest muscle in the body.","It forms most of the shape of the bottom.","It runs from the back of the pelvis to the top of the thigh bone."],"function":["It is worked hard in squats.","It straightens the hip.","It powers climbing stairs, running and standing up from a chair."]}},{"id":"quadriceps","name":"Quadriceps","aliases":["Quads","Quadricep"],"attributes":{"system":"Muscular","region":"Leg & foot","kind":"Muscle","count":2,"size":45},"clues":{"description":["A group of four muscles.","It covers the front of the thigh.","Its four parts join into one tendon around the kneecap."],"function":["It is one of the strongest muscle groups in the body.","It straightens the knee.","It powers kicking, jumping and standing up."]}},{"id":"hamstrings","name":"Hamstrings","aliases":["Hamstring"],"attributes":{"system":"Muscular","region":"Leg & foot","kind":"Muscle","count":2,"size":40},"clues":{"description":["A group of three muscles.","They run down the back of the thigh.","Their tendons can be felt behind the knee on each side."],"function":["They are often strained by sprinters.","They bend the knee.","They also pull the thigh backward at the hip."]}},{"id":"gastrocnemius","name":"Gastrocnemius","aliases":["Calf muscle","Calf"],"attributes":{"system":"Muscular","region":"Leg & foot","kind":"Muscle","count":2,"size":25},"clues":{"description":["A muscle with two bulging heads.","It forms the rounded shape on the back of the lower leg.","It joins the thick tendon that attaches to the heel."],"function":["It is worked hard when you jump.","It points the foot down.","It lifts your heel so you can stand on tiptoe."]}},{"id":"masseter","name":"Masseter","aliases":[],"attributes":{"system":"Muscular","region":"Head","kind":"Muscle","count":2,"size":5},"clues":{"description":["A thick, square-shaped muscle.","It sits at the side of the face, in front of the ear.","You can feel it bulge when you clench your teeth."],"function":["Pound for pound, it is one of the strongest muscles.","It lifts the jaw to close the mouth.","It gives power to biting and chewing."]}},{"id":"knee","name":"Knee","aliases":["Knee joint"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Joint","count":2,"size":10},"clues":{"description":["The largest joint in the body.","It sits in the middle of the leg.","It is protected in front by a small, flat bone."],"function":["It mostly works like a hinge.","It bends and straightens the leg.","It is often injured in sports, like a torn ACL."]}},{"id":"elbow","name":"Elbow","aliases":["Elbow joint"],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Joint","count":2,"size":7},"clues":{"description":["A joint in the middle of the arm.","Three bones meet here.","Its bony point sticks out at the back when you bend the arm."],"function":["It works like a hinge.","It bends and straightens the arm.","It also lets the forearm twist to turn the palm up or down."]}},{"id":"shoulder-joint","name":"Shoulder","aliases":["Shoulder joint"],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Joint","count":2,"size":5},"clues":{"description":["A ball-and-socket joint at the top of the arm.","Its socket is very shallow, like a golf ball on a tee.","A group of four muscles called the rotator cuff holds it together."],"function":["It is the most mobile joint in the body.","It lets the arm swing in almost any direction.","Because it moves so much, it is the joint that dislocates most often."]}},{"id":"hip-joint","name":"Hip","aliases":["Hip joint"],"attributes":{"system":"Skeletal","region":"Pelvis","kind":"Joint","count":2,"size":5},"clues":{"description":["A ball-and-socket joint.","It joins the leg to the pelvis.","The rounded head of the thigh bone sits in a deep cup."],"function":["It carries the weight of the upper body.","It lets the leg swing forward, backward and to the side.","It is one of the most common joints to be replaced in older people."]}},{"id":"ankle","name":"Ankle","aliases":["Ankle joint"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Joint","count":2,"size":7},"clues":{"description":["A joint where the leg meets the foot.","It has two bony bumps, one on each side.","The two lower leg bones grip a foot bone between them."],"function":["It is often sprained by rolling it.","It points the foot up and down.","It carries your full body weight with every step."]}},{"id":"wrist","name":"Wrist","aliases":["Wrist joint"],"attributes":{"system":"Skeletal","region":"Arm & hand","kind":"Joint","count":2,"size":6},"clues":{"description":["A joint where the forearm meets the hand.","It contains eight small bones in two rows.","You can feel your pulse on its thumb side."],"function":["It is where people often wear a watch.","It bends the hand up, down and side to side.","Repetitive typing can squeeze a nerve in a tunnel here."]}},{"id":"achilles-tendon","name":"Achilles tendon","aliases":["Heel cord","Calcaneal tendon"],"attributes":{"system":"Muscular","region":"Leg & foot","kind":"Connective tissue","count":2,"size":15},"clues":{"description":["The thickest and strongest tendon in the body.","It runs down the back of the lower leg.","It connects the calf muscles to the back of the foot."],"function":["It is named after a Greek hero's only weak spot.","It transfers the pull of the calf to the foot.","It lets you push off when you walk, run and jump."]}},{"id":"acl","name":"Anterior cruciate ligament","aliases":["ACL"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Connective tissue","count":2,"size":3.5},"clues":{"description":["A short, tough band of tissue.","It sits deep inside the knee.","It crosses over its partner band to form an X shape."],"function":["Footballers and skiers often tear it.","It keeps the shin bone from sliding forward.","It steadies the knee when you twist or land."]}},{"id":"meniscus","name":"Meniscus","aliases":["Menisci","Knee cartilage"],"attributes":{"system":"Skeletal","region":"Leg & foot","kind":"Connective tissue","count":4,"size":4},"clues":{"description":["C-shaped pads of rubbery cartilage.","There are two in each knee, on the top of the shin bone.","They sit between the ends of the thigh bone and shin bone."],"function":["They are often torn by twisting the knee.","They act as shock absorbers.","They spread out weight and steady the joint."]}},{"id":"cartilage","name":"Cartilage","aliases":["Gristle"],"attributes":{"system":"Skeletal","region":"Whole body","kind":"Connective tissue","count":null,"size":null},"clues":{"description":["A smooth, rubbery tissue that is softer than bone.","It covers the ends of bones in your joints.","It also shapes your ears and the tip of your nose."],"function":["It has no blood vessels, so it heals slowly.","It lets bones glide past each other with little friction.","It cushions joints; wear of it causes osteoarthritis."]}},{"id":"eye","name":"Eye","aliases":["Eyes","Eyeball"],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":2.4},"clues":{"description":["A ball about 2.4 cm across, filled with jelly.","It sits in a bony socket in the skull.","It has a coloured ring with a black hole in the middle."],"function":["It is protected by lids that close many times a minute.","It focuses light onto a layer at the back.","It lets you see."]}},{"id":"cornea","name":"Cornea","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":1.2},"clues":{"description":["A clear, dome-shaped window.","It covers the front of the eye.","It sits over the coloured part and the pupil, and has no blood vessels."],"function":["It is one of the most sensitive tissues in the body.","It does most of the eye's light bending.","Laser eye surgery reshapes it to fix blurry vision."]}},{"id":"iris","name":"Iris","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":1.2},"clues":{"description":["A thin, ring-shaped disc.","It gives the eye its colour.","Its pattern is so unique it can be used like a fingerprint."],"function":["It works like the aperture of a camera.","It controls how much light gets into the eye.","It makes the pupil small in bright light and big in the dark."]}},{"id":"pupil","name":"Pupil","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":0.5},"clues":{"description":["A round, black opening.","It is in the centre of the coloured part of the eye.","It looks black because the light that enters does not come back out."],"function":["It is really a hole, not a solid part.","Light passes through it into the eye.","It gets wider in the dark and narrower in bright light."]}},{"id":"lens","name":"Lens","aliases":["Crystalline lens"],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":0.9},"clues":{"description":["A clear, flexible disc that bulges on both sides.","It sits just behind the coloured ring of the eye.","When it turns cloudy with age, it is called a cataract."],"function":["It fine-tunes focus.","Tiny muscles change its shape to see near or far.","Its stiffening with age is why many older people need reading glasses."]}},{"id":"retina","name":"Retina","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":4},"clues":{"description":["A thin layer of tissue, like wallpaper.","It lines the inside back of the eye.","It contains millions of rods and cones."],"function":["It works like the sensor in a camera.","It turns light into electrical signals.","It sends those signals to the brain through the optic nerve."]}},{"id":"optic-nerve","name":"Optic nerve","aliases":["Optic nerves"],"attributes":{"system":"Nervous","region":"Head","kind":"Other","count":2,"size":5},"clues":{"description":["A thick bundle of over a million nerve fibres.","It runs from the back of each eye toward the brain.","Where it leaves the eye, there is a small blind spot."],"function":["It is a data cable.","It carries signals from the eye to the brain.","The two of them partly cross over at a point called the chiasm."]}},{"id":"ear","name":"Ear","aliases":["Ears","Outer ear","Pinna"],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":6},"clues":{"description":["A curled flap of skin and cartilage on each side of the head.","It keeps growing slowly all through life.","It leads into a short canal that ends at a thin membrane."],"function":["It is a sound collector.","Its shape helps you tell where noises come from.","Its inner parts also help with balance."]}},{"id":"eardrum","name":"Eardrum","aliases":["Tympanic membrane","Ear drum"],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":0.9},"clues":{"description":["A thin, cone-shaped membrane about 1 cm wide.","It sits at the inner end of the canal in the side of the head.","It separates the outer and middle parts of the hearing organ."],"function":["It shakes when sound hits it.","It passes vibrations to three tiny bones.","It can burst from very loud noise or pressure changes."]}},{"id":"cochlea","name":"Cochlea","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":2,"size":1},"clues":{"description":["A tiny tube coiled up like a snail shell.","It sits deep in the inner ear, carved into the skull.","It is filled with fluid and lined with tiny hair cells."],"function":["It turns vibrations into nerve signals.","Different parts of it pick up high and low notes.","Implants named after it can give deaf people a sense of sound."]}},{"id":"tongue","name":"Tongue","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":1,"size":10},"clues":{"description":["A strong, flexible muscle covered in tiny bumps.","It lies on the floor of the mouth.","It is attached underneath by a thin fold of tissue."],"function":["You use it to talk.","It moves food around while you chew and helps you swallow.","It is covered in taste buds that let you taste food."]}},{"id":"taste-buds","name":"Taste buds","aliases":["Taste bud"],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":8000,"size":0.005},"clues":{"description":["Several thousand tiny onion-shaped clusters of cells.","Most are inside the small bumps on the tongue.","Each one is replaced about every two weeks."],"function":["They help you enjoy food.","They tell sweet, salty, sour and bitter apart.","They also sense umami, the savoury flavour."]}},{"id":"nose","name":"Nose","aliases":[],"attributes":{"system":"Sensory","region":"Head","kind":"Sense organ","count":1,"size":5},"clues":{"description":["It sticks out in the middle of the face.","It is made of bone at the top and cartilage at the tip.","It has two openings divided by a wall."],"function":["It warms and moistens the air you breathe.","Its hairs and mucus trap dust and germs.","It holds the cells that let you smell."]}},{"id":"aorta","name":"Aorta","aliases":[],"attributes":{"system":"Cardiovascular","region":"Chest","kind":"Blood vessel","count":1,"size":35},"clues":{"description":["The largest artery in the body, about as wide as a garden hose.","It arches out of the top of the heart like a walking stick.","It runs down in front of the spine into the belly."],"function":["It is the main road for blood.","All blood leaving the left side of the heart goes through it.","It carries oxygen-rich blood to branches that feed the whole body."]}},{"id":"vena-cava","name":"Vena cava","aliases":["Venae cavae","Superior vena cava","Inferior vena cava"],"attributes":{"system":"Cardiovascular","region":"Chest","kind":"Blood vessel","count":2,"size":22},"clues":{"description":["The two biggest veins in the body.","One comes from above and one from below.","Both empty into the right side of the heart."],"function":["They are the end of the line for used blood.","They carry blood that is low in oxygen.","They bring blood back from the whole body to the heart."]}},{"id":"carotid-artery","name":"Carotid artery","aliases":["Carotid arteries","Carotids"],"attributes":{"system":"Cardiovascular","region":"Neck","kind":"Blood vessel","count":2,"size":10},"clues":{"description":["A large artery on each side of the neck.","You can feel a strong pulse just beside the windpipe.","Each one splits into an inner and an outer branch near the jaw."],"function":["Doctors often check your pulse here.","They carry blood to the face and scalp.","They supply most of the blood that reaches the brain."]}},{"id":"jugular-vein","name":"Jugular vein","aliases":["Jugular veins","Jugular"],"attributes":{"system":"Cardiovascular","region":"Neck","kind":"Blood vessel","count":2,"size":15},"clues":{"description":["A big vein on each side of the neck.","The outer one can sometimes be seen bulging when you strain or shout.","The inner one runs beside a big artery in the neck."],"function":["To 'go for' it means to attack someone's weak spot.","It drains blood from the head and neck.","It brings blood from the brain back toward the heart."]}},{"id":"pulmonary-artery","name":"Pulmonary artery","aliases":["Pulmonary arteries","Pulmonary trunk"],"attributes":{"system":"Cardiovascular","region":"Chest","kind":"Blood vessel","count":1,"size":5},"clues":{"description":["A thick vessel leaving the right side of the heart.","It is a short trunk that splits into a left and right branch.","It is the only artery in adults that carries oxygen-poor blood."],"function":["It is the start of a short round trip.","It sends blood away from the heart.","It carries blood to the lungs to pick up oxygen."]}},{"id":"coronary-arteries","name":"Coronary arteries","aliases":["Coronary artery"],"attributes":{"system":"Cardiovascular","region":"Chest","kind":"Blood vessel","count":2,"size":10},"clues":{"description":["Two small arteries that branch off the very start of the aorta.","They wrap around the outside of the heart like a crown.","They run in grooves on the heart's surface."],"function":["The heart's own fuel line.","They feed the heart muscle with oxygen-rich blood.","When one gets blocked, a heart attack can happen."]}},{"id":"femoral-artery","name":"Femoral artery","aliases":["Femoral arteries"],"attributes":{"system":"Cardiovascular","region":"Leg & foot","kind":"Blood vessel","count":2,"size":40},"clues":{"description":["A large artery running down each thigh.","You can feel its pulse in the crease of the groin.","It runs close to the thigh bone and goes behind the knee."],"function":["It is a common entry point for heart catheters.","Injury to it can cause very heavy bleeding.","It is the main blood supply to the leg."]}},{"id":"capillaries","name":"Capillaries","aliases":["Capillary"],"attributes":{"system":"Cardiovascular","region":"Whole body","kind":"Blood vessel","count":10000000000,"size":0.1},"clues":{"description":["The smallest blood vessels in the body.","They are so narrow that red blood cells pass in single file.","Their walls are only one cell thick."],"function":["There are billions of them, reaching almost every cell.","They link the smallest arteries to the smallest veins.","Oxygen and nutrients pass through their walls into the tissues."]}},{"id":"sciatic-nerve","name":"Sciatic nerve","aliases":["Sciatic"],"attributes":{"system":"Nervous","region":"Leg & foot","kind":"Other","count":2,"size":100},"clues":{"description":["The longest and widest nerve in the body.","It is about as thick as a thumb near its top.","It runs from the lower back through the buttock and down the leg."],"function":["Pinching it causes shooting pain down the leg.","It carries signals to and from the back of the thigh and lower leg.","It controls muscles below the knee and gives feeling to the foot."]}},{"id":"teeth","name":"Teeth","aliases":["Tooth"],"attributes":{"system":"Digestive","region":"Head","kind":"Other","count":32,"size":2.3},"clues":{"description":["Hard, white structures set in sockets in the jaws.","They are covered with enamel, the hardest substance in the body.","Adults usually have 32, including four 'wisdom' ones."],"function":["Children lose their first set.","They cut, tear and grind food.","The broad ones at the back crush food before you swallow."]}},{"id":"hair","name":"Hair","aliases":[],"attributes":{"system":"Integumentary","region":"Whole body","kind":"Other","count":5000000,"size":null},"clues":{"description":["Thin strands made of keratin.","They grow out of tiny pockets deep in the skin.","There are about 100,000 of them on the scalp alone."],"function":["The strands themselves are dead, so cutting them does not hurt.","They help keep the body warm.","Tiny muscles can make them stand up, giving you goosebumps."]}},{"id":"fingernails","name":"Fingernails","aliases":["Nails","Fingernail","Nail"],"attributes":{"system":"Integumentary","region":"Arm & hand","kind":"Other","count":10,"size":1.2},"clues":{"description":["Hard, clear plates made of keratin.","They sit on the top of the tips of your fingers.","A pale half-moon shape often shows at their base."],"function":["They grow about 3 mm a month.","They protect the fingertips.","They help you pick up small things and scratch an itch."]}},{"id":"eyelashes","name":"Eyelashes","aliases":["Eyelash","Lashes"],"attributes":{"system":"Integumentary","region":"Head","kind":"Other","count":400,"size":1},"clues":{"description":["Short, curved hairs in a row.","They grow along the edges of the eyelids.","The upper lid has more of them than the lower lid."],"function":["Touching them makes you blink.","They catch dust before it reaches the eye.","They help shade the eye and keep it clean."]}},{"id":"sweat-glands","name":"Sweat glands","aliases":["Sweat gland"],"attributes":{"system":"Integumentary","region":"Whole body","kind":"Gland","count":3000000,"size":0.05},"clues":{"description":["Millions of tiny coiled tubes.","They sit deep in the skin and open as tiny pores.","There are lots on the palms, soles and forehead."],"function":["They work hard during exercise and on hot days.","They release salty water onto the skin.","That fluid evaporates to cool the body down."]}},{"id":"uvula","name":"Uvula","aliases":[],"attributes":{"system":"Digestive","region":"Head","kind":"Other","count":1,"size":1.5},"clues":{"description":["A small, teardrop-shaped piece of soft tissue.","It hangs down at the back of the mouth.","Cartoons often draw it dangling in the throat when a character screams."],"function":["It is part of the soft roof of the mouth.","It helps close off the nose when you swallow.","It makes saliva and can play a part in snoring."]}},{"id":"umbilicus","name":"Belly button","aliases":["Navel","Umbilicus","Bellybutton"],"attributes":{"system":"Integumentary","region":"Abdomen","kind":"Other","count":1,"size":1.5},"clues":{"description":["A small scar in the middle of the stomach area.","It can be an 'innie' or an 'outie'.","It is roughly level with the top of the hip bones."],"function":["It no longer does any job.","It is where a cord once connected you to your mother.","Before birth, food and oxygen came in through that spot."]}}]