Basic Structure & Appearance
Your blood is actually a liquid tissue (a special body part made of liquid), making it different from solid organs like your heart or lungs!
Blood - Facts for Kids
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Facts About Blood For Kids
The word for blood in ancient Greek is ‘haima’, and in Latin it’s ‘sanguis’. Those old languages give us lots of science and medicine words—like hemoglobin (Greek root ‘hema’) and sanguineous (Latin root ‘sanguis’)!
Your blood comes in four main types: A, B, AB, and O, and each type is like a special code that tells doctors exactly which blood is safe to give you and helps keep you healthy!
If you looked at your blood under a microscope (a tool that makes tiny things look bigger), you’d see it’s made up of tiny round cells floating in a yellowish liquid called plasma (blood juice)!
Red blood cells are shaped like tiny donuts without holes, which helps them squeeze through the smallest blood vessels (tubes) in your body!
A single drop of blood contains about 250 million red blood cells, which is more than the ~4,000 stars you can see in the darkest night sky!!
White blood cells, your body’s guardian angels (protectors), can change their shape like superheroes to catch bad germs!
Your blood is bright red when it carries oxygen and darker red when it needs more oxygen – like a color-changing magic potion!
Blood platelets are so tiny that it would take about 10–60 of them lined up to match the width of a single hair on your head!
Your blood makes up about 8-9% of your body weight, which means a 70-pound child has about 5–6 pounds of blood!
Function & Purpose
Your blood travels through about 60,000 miles (ca. 96,561 km) of blood vessels (tubes) – that’s enough to go around the Earth more than twice!
At rest, your heart pumps about 5 liters of blood each minute — that’s around 1.3 gallons — enough to fill a small fish tank every minute!
Red blood cells travel through your body at about 0.3 millimeters per second in tiny capillaries, which is slower than an ant’s walk!
Your blood helps keep your body temperature (how hot or cold you are) just right at 98.6°F (37°C), like a built-in thermostat (temperature controller)!
Each red blood cell makes about 172,800 trips around your body in its 100–120 days lifetime!
Your blood carries oxygen (air your body needs) from your lungs to every single one of your over 30 trillion cells!
White blood cells can remember germs they’ve fought before, like keeping a diary of bad guys to watch out for!
Your blood helps heal cuts by forming scabs, which are like natural Band-Aids your body makes!
Blood carries messages in the form of hormones (chemical messengers), like billions of tiny mail carriers delivering important letters throughout your body!
Your blood helps remove waste products (body trash) from your cells, like a cleanup crew working 24 hours a day!
Health & Care
Eating foods rich in iron, like spinach and lean meat, helps your body make strong red blood cells!
Exercise helps your blood flow better, making your heart stronger and your body healthier!
Drinking plenty of water helps your blood flow smoothly through your vessels (tubes)!
Your doctor can learn about your health by looking at just a tiny drop of your blood!
Getting enough sleep helps your body make new blood cells while you rest!
Wearing a helmet when bike riding protects your blood vessels (tubes) in your brain from injury!
Your blood can fight off most germs before they make you sick, like having millions of tiny soldiers protecting you!
A healthy diet with lots of vitamins (good stuff in food) helps your bone marrow (inside your bones) make strong blood cells!
Regular check-ups help doctors make sure your blood is healthy and doing its job!
Washing your hands helps prevent germs from getting into your bloodstream (blood flow)!
Amazing Abilities
Your bone marrow (soft inside of bones) makes about 2 million new red blood cells every second!
White blood cells can live anywhere from a few days to several months, always ready to protect you!
Your blood can start forming clots (sticky patches) within about 20 seconds of getting a cut!
Blood can carry oxygen 1about 70 times more efficiently (better) than plain water!
Your blood vessels (tubes) can constrict (get smaller) and dilate (get bigger) to help control your body temperature!
White blood cells can move through your body walls to chase down germs!
Your blood can fight off infections (sickness from germs) you’ve never had before by making new antibodies (germ fighters)!
Blood platelets (tiny sticky pieces) can stick together like Velcro to help heal wounds!
Your blood, combined with your lungs, can carry enough oxygen to help you hold your breath for about 1 to 2 minutes!
The iron in your blood is strong enough to help make a small nail if it were extracted (taken out) and melted!
Growth & Development
A baby has about 1 cup (0.24 liters) of blood in their body, while an adult has 1.2 to 1.5 gallons (about 4.5–6 liters)!
Your bone marrow (soft inside of bones) produces (makes) all your blood cells in special blood-making factories!
Red blood cells live for about 120 days before being replaced by new ones!
Your blood type is determined (decided) before you’re born and stays the same your whole life!
Teenagers usually make blood cells faster than younger children because they’re growing so quickly!
Your body makes different amounts of blood cells depending on what you need – like when you’re sick or exercising!
The amount of blood in your body increases (gets bigger) as you grow taller and bigger!
Your blood vessels (tubes) grow longer as you get taller, like a growing garden hose system!
Blood cells are made faster when you exercise regularly (often), making you stronger!
Your body can adjust (change) how many blood cells it makes based on where you live — making more if you live in high mountains!
