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.