Human Body Facts
Human Body Facts
The brain uses over a quarter of the oxygen used by the human body.
Your heart beats around 100000 times a day, 36500000 times a year and over a billion times if you live beyond 30.
Red blood cells carry oxygen around the body. They are created inside the bone marrow of your bones.
The colour of a humans skin is determined by the level of pigment melanin that the body produces. Those with small amounts of melanin have light skin while those with large amounts have dark skin.
Adult lungs have a surface area of around 70 square metres.
Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams. More eye facts.
The smallest bone found in the human body is located in the middle ear. The staples (or stirrup) bone is only 2.8 millimetres long.
Infants blink only once or twice a minute while adults average around 10.
As well as having unique fingerprints, humans also have unique tongue prints.
The left side of your body is controlled by the right side of your brain while the right side of your body is controlled by the left side of your brain.
Antibiotics are only effective against bacteria, they won't help in fighting off a virus.
It takes the body around 12 hours to completely digest eaten food.
Your sense of smell is around 10000 times more sensitive than your sense of taste.
Your nose and ears continue growing throughout your entire life.
human brain
The human brain is like a powerful computer that stores our memory and controls how we as humans think and react. It has evolved over time and features some incredibly intricate parts that scientists still struggle to understand.
The brain is the center of the human nervous system, controlling our thoughts, movements, memories and decisions.
With evolution, the human brain has become more and more complicated, many of its interesting properties are still not well understood by scientists.
The brain contains billions of nerve cells that send and receive information around the body.
The human brain is over three times as big as the brain of other mammals that are of similar body size.
Each side of the brain interacts largely with just one half of the body, but for reasons that are not yet fully understood, the interaction is with opposite sides, the right side of the brain interacts with the left side of the body, and vice versa.
The largest part of the human brain is called the cerebrum. Other important parts include corpus callosum, cerebral cortex, thalamus, cerebellum, hypothalamus, hippocampus and brain stem.
The human brain is protected by the skull (cranium), a protective casing made up of 22 bones that are joined together.
The brain of an adult human weighs around 3 pounds (1.5 kg). Although it makes up just 2% of the body's weight, it uses around 20% of its energy.
The brain is suspended in Cerebrospinal fluid, effectively floating in liquid that acts as both a cushion to physical impact and a barrier to infections.
Diseases of the brain include Alzheimer’s disease, Parkinson's disease and multiple sclerosis. Diseases such as these can limit the normal function of the human brain.
Most strokes result from a blood clot in the brain that blocks the local blood supply, this causes the damage or destruction of nearby brain tissue and a wide range of stroke symptoms.
Blood
Blood makes up around 7% of the weight of a human body.
Blood contains red blood cells, white blood cells and platelets.
These blood cells float in a yellow liquid called blood plasma. Blood plasma is made up of 90% water and also contains various nutrients, electrolytes, gases, proteins, glucose and hormones.
Blood plasma can be separated from the cells by spinning blood in a device known as a centrifuge until the cells collect at the bottom of the tube.
Red blood cells have the important job of carrying oxygen around the body. They also contain a protein called hemoglobin. Hemoglobin contains iron which combines with oxygen to give hemoglobin and our blood, a red color.
Red blood cells develop in bone marrow and circulate in the body for around 120 days.
White blood cells are an important part of the body’s immune system. They defend against certain bacteria, viruses, cancer cells, infectious diseases and other unwanted materials.
Platelets help blood clot in order to limit bleeding when your skin is cut. Blood clots can occasionally have negative effects, if they form in blood vessels going to the brain they can cause a stroke while clotting in a blood vessel going to the heart can lead to a heart attack.
As well as delivering important substances to our cells, blood also helps take away unwanted waste products.
Grouping human blood types can be a difficult process and there are currently around 30 recognized blood types (or blood groups). You might be familiar with the more simplified “ABO” system which categorizes blood types under O, A, B and AB. Do you know which blood type you are?
Many generous humans around the world give blood donations every year. This blood is used in important blood transfusions or made into medication.
There are strict rules that limit the number of people who can volunteer blood donations. These include screening processes that test for diseases that could be transmitted by a blood transfusion as well as ensuring recovery time for the donor’s body to replace its own blood.
One of the principal signs of life for humans is blood pressure, this is the measure of pressure that circulating blood has on the walls of blood vessels. Blood pressure is usually taken from a person’s upper arm. Although averages vary from person to person, a general human being is known to have a normal blood pressure of around 112/64 mmHg. High blood pressure can increase the risk of a stroke or heart attack.
Skin Facts
Learn some fun skin facts for kids. The skin of both humans and other animals can be much more than just a physical line of defense.
Your skin performs important functions that allow you to live a normal life, you might not notice it happening but you can be sure your skin is doing its part to keep your body healthy. Read on and enjoy the following interesting facts about skin.
- Skin is the human body’s largest organ (an organ is a group of tissues that work together to perform functions in your body, others include your brain, heart and lungs).
- Your skin performs a range of different functions which include physically protecting your bones, muscles and internal organs, protecting your body from outside diseases, allowing you to feel and react to heat and cold and using blood to regulate your body heat.
- The layers of mammal skin include the epidermis, dermis and subcutis.
- The outer layer of your skin is the epidermis, it is found thickest on the palms of your hands and soles of your feet (around 1.5mm thick).
- The subcutis (or hypodermis) is the deepest layer of your skin, as well as storing fat, it also contains blood vessels, hair follicle roots and nerves.
- If skin is severely damaged then it may try to heal by forming scar tissue. Scar tissue is not the same as normal skin tissue, it often appears discolored and lacks sweat glands and hair.
- The color of human skin depends on the amount of pigment melanin that the body produces. Small amounts of melanin result in light skin while large amounts result in dark skin.
- Areas that experience repeated friction or pressure can form tough, thick skin known as a callus. Common examples of calluses can be seen on the hands of tennis players and the fingertips of guitarists.
- A large amount of the dust in you home is actually dead skin.
- All mammals have some hair on their skin, even if it isn’t easy for you to see.
- Rhinoceros’s are protected by thick skin which can be between 1.5cm and 5cm deep.
- Although polar bears have both white and transparent (see through) fur, their skin is actually black.
- Amphibians such as frogs have unique skin. Rather than drinking water, frogs actually soak it into their body through their skin. They also use their skin to absorb around half the air they need.
- Snakes have smooth, dry skin.
- A number of different sea creatures, such as sea lice and barnacles, attach themselves to the skin of whales, making it their home.
- Some fruits and vegetables are known to have ‘skins’, these include bananas, oranges, apples and potatoes.
lungs
amazing organs that allow us to breathe in the oxygen we need to live as well as breathe out the waste product carbon dioxide. Read on and enjoy all the interesting facts about lungs.
The primary functions of your lungs are to transport oxygen from the air you breathe into your bloodstream while taking away carbon dioxide, which is released into the air when you breathe out.
Most vertebrate animals (animals with spines) have two lungs.
Your left and right lungs aren’t exactly the same. The lung on the left side of your body is divided into two lobes while the lung on your right side is divided into three. The left lung is also slightly smaller, allowing room for your heart.
Can you live without one lung? Yes you can, it limits your physical ability but doesn’t stop you from living a relatively normal life. Many people around the world live with just one lung.
People who have a large lung capacity can send oxygen around their body faster. You can increase you lung capacity with regular exercise.
When resting, the average adult breathes around 12 to 20 times a minute.
An average person breathes in around 11,000 litres of air every day.
The study of lung diseases is known as pulmonology.
As well as other parts of your body and your general health, smoking is bad for your lungs. Smoking can cause lung cancer among other lung affecting diseases.
Asthma is a common disease that affects the lungs. Asthma attacks happen when your airways narrow after being irritated. The narrow airways make it hard for you to breathe in air.
Pneumonia is a dangerous disease that makes it harder for your lungs to absorb oxygen from the air you breathe.
Other lung diseases include emphysema, tuberculosis and bronchitis.
Eyes
Eyes detect light and allow us to see.
The information our eyes receive is sent to our brain along the optic nerve. This information is then processed by our brain and helps us make appropriate decisions, for example if you can see an object flying in your direction then you will probably move quickly out of the way.
Around 95% of animals have eyes. Some are very simple, just picking up light and dark conditions while others are more complex, allowing for the recognition of shapes, color and depth.
Like humans, some animals have eyes placed close together that allow for improved depth perception, others have eyes spread further apart (often on opposite sides of their head, as in horses) to allow for a greater field of view and an early warning against potential predators.
The light sensitive tissue lining the inner surface of your eye is known as the retina, acting in a similar way to film in a traditional camera.
Cone cells in the retina detect color while rod cells detect low light contrasts.
The part of the eye that allows us to focus on different things in known as the lens, it changes shapes so we can focus on objects at various distances.
The cornea is the transparent covering of the iris and pupil, along with the lens it refracts light so it can be projected onto the retina.
The central opening of your eye is known as the pupil, it changes size depending on the amount of light.
The colored area around the pupil is called the iris, it controls the size of the pupil and can be colored brown, blue, green or other colors and shades depending on the person.
Scientists believe that animal eyes evolved around 500 million years ago, beginning in simple form (perhaps just distinguishing light and dark) but giving a distinct advantage. This advantage led to eyes evolving quickly amongst animals (by evolutionary standards) as those without the ability to see struggled to survive against those that could.
Throughout the animal kingdom there are many different types of eyes, for example the human eye is very different to the compound eye of a fly which is better at detecting fast movements.
Human eyes contain a small blind spot where the optic nerve passes through the retina. Our brains use information from the other eye to fill in the vision gap so it is rarely, if ever, noticed.
Glasses and other protective equipment are often worn by humans to protect the eyes from UV rays or during various dangerous activities such as welding.
Glasses and contact lenses are worn to correct common sight conditions such as short and long sightedness.
foods.
McDonald’s fast food chains employ over 1.5 million people around the world. More fast food facts.
Different parts of the world have their own local cuisine. The diets and general food habits of various cultures depend on social, religious, economic and safety factors as well as the availability of different foods.
Examples of food and cuisine that are popular or famous in certain areas of the world include hummus in the Middle East, apple pie in the USA, raw fish in Japan, cheese in France, roast meat and vegetables in England, curry in India and tortillas in Mexico.
There are around 2000 different plant types that humans use to cultivate food.
Examples of popular vegetables include lettuce, carrots, asparagus, cauliflower, broccoli, spinach, potatoes and onions.
Cutting onions releases a gas which causes a stinging sensation when it comes into contact with your eyes. Your body produces tears to dilute the irritant and remove it from your eyes.
China is the largest producer of garlic, producing over 10 million tons in 2008 and accounting for over 75% of world output.
Examples of popular fruits include apples, oranges, pears, strawberries, peaches, bananas, apricots and grapes.
India is the world’s largest producer of bananas, producing nearly 22 million tons in 2007.
Humans use many different methods for gathering food which include farming, hunting, gardening, foraging and fishing.
Humans eat meat from a number of different animals, common examples include meat from chickens, cows, sheep and pigs. Other food products that come from animals include milk, eggs and honey.
Although humans are omnivores (eating both plants and animals), many people choose not to eat meat and fish, they are known as vegetarians. Those who don’t eat or use any products made from animals (including eggs, dairy products and honey) are known as vegans.
Food for human consumption is typically made from plants and animals but we also eat other products such as fermented foods and fungus (mushrooms, truffles etc).
Cooking is an important part of food preparation that involves applying heat. In most cases this transforms the chemical make up of food, altering its texture, flavor, nutritional properties and appearance.
Types of equipment used in the cooking process include ovens, microwaves, toasters, grills, pots and frying pans.
Various cooking methods include boiling, simmering, steaming, sautéing, pan frying and deep-frying.
Around 70 million people suffer from food poisoning every year with around 7 million of these cases being fatal. Careful food storage, temperature control and preparation is necessary to avoid potentially dangerous bacteria, toxins and viruses.
Around 8% of children and 2% of adults have some kind of food allergy, this occurs when the body’s immune system incorrectly assumes a certain food protein is harmful and attacks it. Common examples of food allergies include reactions to peanuts, gluten and shellfish.
Fast food
Fast food (or junk food) is the name given to food that can be prepared and served quickly, often served at basic restaurants or in packaged form for convenient takeaway/takeout. It is typically inexpensive to buy but unhealthy to eat.
Popular forms of fast food include burgers, fries, pizza, fish and chips, kebabs and fried chicken.
Well known fast food franchises and restaurants include McDonalds, Kentucky Fried Chicken (KFC), Pizza Hut, Taco Bell and Burger King.
As well as at restaurants, fast food is commonly sold at convenience stores and gas stations. Examples of this include hotdogs, meat pies and doughnuts.
Fast food is often highly processed and produced on a large scale to decrease costs. Ingredients and various menu items are typically prepared at a different location before being sent to restaurants to be cooked, reheated or quickly put together for the customer’s convenience.
While hamburgers, fries and pizza are seen as traditional fast foods, countries throughout the world sell all types of fast food that may not be so well known. Some examples of these include kebabs, Chinese takeaways (friend noodles, rice and meat dishes), sushi and bento type foods in Japan and fish and chips in the UK, New Zealand and Australia.
Consumers in the USA spend over $100 billion on fast food every year.
McDonald’s is arguably the worlds most well known fast food chain. There are McDonald’s restaurants found in over 100 countries around the world and they serve over 40 million customers every day.
Due to increased awareness of public health and obesity levels, efforts have been made to improve fast food menus by lowering fat levels or at least offering healthier alternatives. While these health concerns are generating more attention, fast food is still linked to worldwide weight gain problems, increased diabetes risks and healthcare costs.