Natural and Social Science

11.- THE EARS

Did you hear something? Maybe the sound you heard was as quiet as your cat licking her paws. Or maybe it was loud, like a siren going by. Sounds are everywhere, and you have two cool parts on your body that let you hear them all: your ears!

Your ears are in charge of collecting sounds, processing them, and sending sound signals to your brain. And that’s not all — your ears also help you keep your balance. So if you bend over to pick up your cat, you won’t fall down — or even worse — fall on your cat. Meow!

The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts all work together so you can hear and process sounds.

The Outer Ear: Catch the Wave

The outer ear is called the pinna or auricle (say: or-ih-kul). This is the part of the ear that people can see. It’s what people pierce to wear earrings and what your friend whispers into when it’s time for a secret. The main job of the outer ear is to collect sounds, whether they’re your friend’s whispers or a barking dog.

The outer ear also includes the ear canal, where wax is produced. Earwax is that gunky stuff that protects the canal. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean. So earwax isn’t just gross. It’s gross and useful.

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Puaaggg!!! Lice!!!!

Scratch scratch. Scratch. Your head is feeling really itchy. Could it be lice?

If so, you're not alone. Every year, between 6 and 12 million people worldwide get head lice. Most of those millions are kids. Any kid who goes to school has probably already heard about lice. They can spread easily at schools, so if one kid gets them, the rest of the class might get them, too. What can you do? Let's find out.

What Are Lice?

Lice are very, very small insects. In fact, they are so tiny that you can barely see them! Each louse (the name for one of the lice) is brown and gray and only about the size of a sesame seed.

Lice are parasites (say: pah-ruh-sytes), which means that they live off other living things. Head lice need to be next to skin to survive - and the warmth of your skin is a perfect place for them to live. Lice eat tiny amounts of blood (much less than a mosquito does) for their nourishment and use their sticky little feet to hold on to hair. Gross!

When lice start living in hair, they also start to lay eggs, or nits. Lice can survive up to 30 days on a person's head and can lay eight eggs a day. Lice attach their nits to pieces of hair, close to the scalp. If you see a small, oval blob on a strand of hair, that's probably a nit. If these little eggs are yellow, tan, or brown, the lice haven't hatched yet. If the eggs are white or clear, the lice have hatched.

Although they don't hurt, lice sometimes can irritate the skin and make it itchy (especially at night). Too much scratching can lead to scalp infections.

Life Without Lice

Sure, lice aren't so nice, but there are things you can do to keep them away. To help prevent lice:

• If your friend has lice, don't give the lice any chance to spread to you. Avoid putting your heads together or sharing stuff that could contain lice, such as hats or combs.
• Don't try on hats that belong to other kids.
• Never share a comb, brush, barrettes, or other hair accessories. Use your own, and don't lend them to anyone else.
• Always use your own sleeping bag and pillow when sleeping away from home.

Sharing is usually a great idea - except when you're sharing lice!

10.- THE EYES

Which part of your body lets you read the back of a cereal box, check out a rainbow, and see a softball heading your way? Which part lets you cry when you’re sad and makes tears to protect itself? Which part has muscles that adjust to let you focus on things that are close up or far away? If you guessed the eye, you’re right!

Your eyes are at work from the moment you wake up to the moment you close them to go to sleep. They take in tons of information about the world around you — shapes, colors, movements, and more. Then they send the information to your brain for processing so the brain knows what’s going on outside of your body.

You can see that the eye’s pretty amazing. So, come on — let’s take a tour of its many parts.

The Parts of the Eye

You can check out different parts of the eye by looking at your own eye in the mirror or by looking at (but not touching) a friend’s eye. Some of the eye’s parts are easy to see, so most friends will say OK. Most friends won’t say OK if you ask to see their liver!

               

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9.- SKIN AND HAIR

Quick! What’s the body’s biggest organ?

You might be surprised to find out it’s the skin, which you might not think of as an organ. No matter how you think of it, your skin is very important. It covers and protects everything inside your body. Without skin, people’s muscles, bones, and organs would be hanging out all over the place. Skin holds everything together. It also:

• protects our bodies
• helps keep our bodies at just the right temperature
• allows us to have the sense of touch

Don’t Miss Your Epidermis

The skin is made up of three layers, each with its own important parts. The layer on the outside is called the epidermis (say: eh-pih-dur-mis). The epidermis is the part of your skin you can see.

Look down at your hands for a minute. Even though you can’t see anything happening, your epidermis is hard at work. At the bottom of the epidermis, new skin cells are forming.

When the cells are ready, they start moving toward the top of your epidermis. This trip takes about 2 weeks to a month. As newer cells continue to move up, older cells near the top die and rise to the surface of your skin. What you see on your hands (and everywhere else on your body) are really dead skin cells.

Dermis = Lots of Blood Vessels

Your dermis is also full of tiny blood vessels. These keep your skin cells healthy by bringing them the oxygen and nutrients they need and by taking away waste. These blood vessels are hard to see in kids, but you might get a better look if you check out your grandparents’ skin. As the dermis gets older, it gets thinner and easier to see through.

The Third Layer Is Subcutaneous Fat

The third and bottom layer of the skin is called the subcutaneous (say: sub-kyoo-tay-nee-us) layer. It is made mostly of fat and helps your body stay warm and absorb shocks, like if you bang into something or fall down. The subcutaneous layer also helps hold your skin to all the tissues underneath it.

This layer is where you’ll find the start of hair, too. Each hair on your body grows out of a tiny tube in the skin called a follicle (say: fah-lih-kul). Every follicle has its roots way down in the subcutaneous layer and continues up through the dermis.

You have hair follicles all over your body, except on your lips, the palms of your hands, and the soles of your feet. And you have more hair follicles in some places than in others — there are more than 100,000 follicles on your head alone!

Your hair follicles rely on your sebaceous glands to bring on the shine. Connected to each follicle in the dermis layer is a tiny sebaceous gland that releases sebum onto the hair. This lightly coats the hair with oil, giving it some shine and a little waterproofing.

When you think of your hair, you probably think of the hair on your head. But there’s hair on almost every part of your body. (Some places that don’t have hair include the lips, the palms of the hands, and the soles of the feet.)

Some of the hair on your body is easy to see, like your eyebrows and the hair on your head, arms, and legs. But other hair, like that on your cheek, is almost invisible.

Depending on where it is, hair has different jobs. The hair on your head keeps your head warm and provides a little cushioning for your skull. Eyelashes protect your eyes by decreasing the amount of light and dust that go into them, and eyebrows protect your eyes from sweat dripping down from your forehead.

Hair Comes From Where?

Whether hair is growing out of your head, arm, or ankle, it all rises out of the skin in the same way. It starts at the hair root, a place beneath the skin where cells band together to form keratin (the protein that hair is made of). The root is inside a follicle (say: fol-ih-kul), which is like a small tube in the skin.

As the hair begins to grow, it pushes up from the root and out of the follicle, through the skin where it can be seen. Tiny blood vessels at the base of every follicle feed the hair root to keep it growing. But once the hair is at the skin’s surface, the cells within the strand of hair aren’t alive anymore. The hair you see on every part of your body contains dead cells. That’s why it doesn’t cause pain when someone cuts your hair with scissors!

Nearly every hair follicle is attached to a sebaceous (say: sih-bay-shus) gland, which is sometimes called an oil gland. These sebaceous glands produce oil, which makes the hair shiny and a bit waterproof. Sometimes, like during puberty, these glands can pump out too much oil and a person’s hair may look greasy. Time for a shampoo!!

GEOGRAPHY

For those of you who want to keep on learning Geography.

Interactive maps

Reviewing: CIRCULATION

Click on these links to see the animations that would help you studying about circulation.

Blood system

The heart beat

Heart labelling

 

Play and check your knowledge

HUMAN BODY GAMES

 

Ready for more?

Do you want to keep on trying?? Answer the following quizzes then:

THE CARDIOVASCULAR SYSTEM

THE RESPIRATORY SYSTEM

THE URINARY SYSTEM

THE LOCOMOTOR SYSTEM

THE DIGESTIVE SYSTEM

THE NERVOUS SYSTEM

 

A Glossary of Medical Words

Symptoms, inhaler, tonsillectomy - what do all those medical words mean?

Check out this virtual glossary for lots of easy-to-read definitions.

Once upon a time... THE BRAIN

More questions: THE RESPIRATORY SYSTEM

                                     

1. Name 3 parts of the respiratory system.
2. Where do we breathe in?
3. What do we breathe in?
4. Which part of the air do we need?
5. Which part of the respiratory system is like sacks?
6. How many lungs do we have?
7. What does the nose do?
8. Where does the oxygen pass into the blood?
9. Which part of the respiratory system is a tube?
10. What passes from the lungs into the blood?

Learn a bit more about the BRAIN

How do you remember the way to your friend’s house? Why do your eyes blink without you ever thinking about it? Where do dreams come from? Your brain is in charge of these things and a lot more.

In fact, your brain is the boss of your body. It runs the show and controls just about everything you do, even when you’re asleep. Not bad for something that looks like a big, wrinkly, gray sponge.

Your brain has many different parts that work together. We’re going to talk about these five parts, which are key players on the brain team:

1. cerebrum (say: suh-ree-brum)
2. cerebellum (say: sair-uh-bell-um)
3. brain stem
4. pituitary gland (say: puh-too-uh-ter-ee gland)
5. hypothalamus (say: hy-po-thal-uh-mus)

The Biggest Part: the Cerebrum

The biggest part of the brain is the cerebrum. The cerebrum makes up 85% of the brain’s weight, and it’s easy to see why. The cerebrum is the thinking part of the brain and it controls your voluntary muscles — the ones that move when you want them to. So you can’t dance — or kick a soccer ball — without your cerebrum.

When you’re thinking hard, you’re using your cerebrum. You need it to solve math problems, figure out a video game, and draw a picture. Your memory lives in the cerebrum — both short-term memory (what you ate for dinner last night) and long-term memory (the name of that roller-coaster you rode on two summers ago). The cerebrum also helps you reason, like when you figure out that you’d better do your homework now because your mom is taking you to a movie later.

The cerebrum has two halves, with one on either side of the head. Some scientists think that the right half helps you think about abstract things like music, colors, and shapes. The left half is said to be more analytical, helping you with math, logic, and speech. Scientists do know for sure that the right half of the cerebrum controls the left side of your body, and the left half controls the right side.

A SPELLING BEE GAME

It’s time for a spelling bee!

Try to spell 5 words related to health.

Good luck!!

                                          

 

Now that you are having fun, why not testing your knowledge on the nervous system and do this

quiz.

8.- THE BRAIN AND THE NERVOUS SYSTEM

NERVOUS SYSTEM - I’M SENSING SOMETHING

Since you’re reading this page, we figure you’ve got a nervous system. If you were an insect you would also have a nervous system, but it would be a lot simpler. Even animals that don’t think have simple nervous systems called nerve nets that help them move.

Your nervous system is divided into two parts. Your central nervous system includes your brain and your spinal cord. Your peripheral nervous system is made up of the network of neurons that spans your organs, muscles, and body. The neurons in both systems work together to help you think, survive, and change the world around you.

WHAT DOES THIS SYSTEM DO?

The nervous system is about action and senses. Animals are able to sense what is going on in their surroundings and do something in reaction to that input. If you see a bike that might hit you, you jump out of the way. In that example, your nervous system was involved in many ways. Your eyes saw the bike, your brain figured out the bike might hit you, and your brain told your muscles to make your legs jump out of the way. You sensed and then acted.

The nervous system also senses activity inside of your body. Most of the nervous system response inside of your body is not in your control. Your body automatically senses and reacts to stimulus. Think about eating your lunch. As you eat, your nervous system triggers the start of digestion and release of many hormones and enzymes throughout your body.

INTERACTING WITH OTHER SYSTEMS

Your nervous system interacts with every other system in your body. In the same way that all of your cells need oxygen transported by the circulatory system, all of your tissues and organs require instruction and direction from the nervous system. There is obvious interaction between your muscles and your nervous system. That interaction helps you move around and interact with your environment.

There are many hidden interactions going on within your body. Your endocrine system works closely with your brain and central nervous system to control the creation of specific hormones and enzymes. Your digestive and excretory systems work with the nervous system in both conscious and unconscious ways. While digestion goes on without your thoughts, eating, peeing, and pooping are under your control.

PARTS OF THE SYSTEM

The nervous system is made up of nervous tissues that are, in turn, made up of many types of neurons. There are billions of neurons connected throughout your body. These neurons are connected end to end and transmit electrical impulses from one point to another.

Your peripheral nervous system has two types of neurons that are constantly at work. Neurons that send impulses from the central nervous system to your limbs and organs are called efferent neurons. Neurons that receive sensory information and transmit to the central nervous system are called afferent neurons. Therefore, as the stimulus is received, the afferent neurons work and as reaction is needed, the efferent neurons go to work. Afferent=Receive. Efferent=Act. The words are really close to each other, that’s why repeated the idea.

Once upon a time... BREATHING

Game: Inside the Respiratory System

 

The Respiratory system

You breathe in. You breathe out. But what's happening inside? Watch this movie and find out!

               

7.- RESPIRATORY SYSTEM

RESPIRATORY SYSTEM - ALL ABOUT BREATHING

Your respiratory system is all about exchanging gases with the environment. Some animals such as amphibians are able to exchange gases through their moist skin. Fish have gills while mammals, birds, and reptiles have lungs. Your respiratory system is made of your nose and mouth, a tube called the pharynx, another tube called the trachea, and your lungs. You have two lungs and the exchange of gases between the circulatory and respiratory systems happens in the lungs.

WHAT DOES THIS SYSTEM DO?

Animals need oxygen (O) to survive. In fact, all organisms need oxygen to complete the process to burning glucose for fuel. Even protists and plants need oxygen, but as you become more active, you need a lot of oxygen. That’s where your respiratory system comes in.

It’s purpose is to bring oxygen into your body. One of the products of cellular respiration is carbon dioxide. Your respiratory system also helps your body get rid of that carbon dioxide. While you have lungs, fish have gills that serve as the location for that transfer of gases. Whatever animal you study, oxygen is taken in and carbon dioxide let out.

INTERACTING WITH OTHER SYSTEMS

We already mentioned the circulatory system. With gases like oxygen and carbon dioxide (CO₂), other compounds can be brought into the body by the respiratory system. Smoke can clog the alveoli in your lungs. You can inhale viruses and bacteria that could get you sick. You can also take in larger chemical compounds that can poison your body. All of these compounds can enter your blood stream via your respiratory system.

Although it does not happen in all animals, your respiratory system also interacts with your digestive system. Your mouth and pharynx are both used to swallow and to breathe. There is a branching point where you will find the epiglottis that directs food to your stomach and air to your lungs. Your respiratory system even connects with the nervous system in your nose where you smell.

PROBLEMS WITH RESPIRATION

What can go wrong with your respiratory system? So many things can go wrong with this system. It is very vulnerable to both toxins and diseases. Some diseases such as pneumonia can cause your lungs to fill with fluid and you are no longer able to take in enough oxygen for your body.

Smokers can have a build up of tar and clog the alveoli in the lungs and decrease the amount of oxygen your body can take in. An extreme disease called emphysema actually destroys the tissues in your lungs and the tissue can never be regenerated. Individuals that get emphysema are often forced to breathe pure oxygen to survive.

RESPIRATORY SYSTEM - ALL ABOUT BREATHING Your respiratory system is all about exchanging gases with the environment. Some animals such as amphibians are able to exchange gases through their moist skin. Fish have gills while mammals, birds, and reptiles have lungs. Your respiratory system is made of your nose and mouth, a tube called the pharynx, another tube called the trachea, and your lungs. You have two lungs and the exchange of gases between the circulatory and respiratory systems happens in the lungs. WHAT DOES THIS SYSTEM DO? Animals need oxygen (O) to survive. In fact, all organisms need oxygen to complete the process to burning glucose for fuel. Even protists and plants need oxygen, but as you become more active, you need a lot of oxygen. That’s where your respiratory system comes in. It’s purpose is to bring oxygen into your body. One of the products of cellular respiration is carbon dioxide. Your respiratory system also helps your body get rid of that carbon dioxide. While you have lungs, fish have gills that serve as the location for that transfer of gases. Whatever animal you study, oxygen is taken in and carbon dioxide let out. INTERACTING WITH OTHER SYSTEMS We already mentioned the circulatory system. With gases like oxygen and carbon dioxide (CO2), other compounds can be brought into the body by the respiratory system. Smoke can clog the alveoli in your lungs. You can inhale viruses and bacteria that could get you sick. You can also take in larger chemical compounds that can poison your body. All of these compounds can enter your blood stream via your respiratory system. Although it does not happen in all animals, your respiratory system also interacts with your digestive system. Your mouth and pharynx are both used to swallow and to breathe. There is a branching point where you will find the epiglottis that directs food to your stomach and air to your lungs. Your respiratory system even connects with the nervous system in your nose where you smell. PROBLEMS WITH RESPIRATION What can go wrong with your respiratory system? So many things can go wrong with this system. It is very vulnerable to both toxins and diseases. Some diseases such as pneumonia can cause your lungs to fill with fluid and you are no longer able to take in enough oxygen for your body. Smokers can have a build up of tar and clog the alveoli in the lungs and decrease the amount of oxygen your body can take in. An extreme disease called emphysema actually destroys the tissues in your lungs and the tissue can never be regenerated. Individuals that get emphysema are often forced to breathe pure oxygen to survive. // // RELATED LINKS - Chem4Kids: Metabolism - Chem4Kids: Enzymes - Geography4Kids: Populations - Geography4Kids: Carbon Cycle - Geography4Kids: Oxygen Cycle - Geography4Kids: Nitrogen Cycle

- Overview - Regulation - Skeletal - Muscular - Circulatory > Respiratory - Digestive - Excretory - Nervous - Endocrine - Integumentary - Immune - Lymphatic MORE BIOLOGY TOPICS Custom Search * The custom search only looks at Rader’s sites. // //

Once upon a time... THE DIGESTION

Today's questions: THE DIGESTIVE SYSTEM

                                    

1. Name 5 parts of the digestive system.
2. Which part of the digestive system is like a bag?
3. Which part of the digestive system is a very long, thin tube?
4. Where do the teeth chew the food?
5. Where does the food mix with the gastric juices?
6. Where does solid waste form?
7. Where does the food mix with saliva?
8. What connects the mouth and the stomach?
9. Where do the nutrients pass into the blood?
10. Where does the food turn into a thick liquid?
11. Name 5 nutrients.
12. Name 3 foods that contain protein.
13. Name 3 foods that contain vitamins.
14. Name 2 foods that are good for your teeth.
15. Which nutrient helps us grow?
16. Which nutrient gives us energy?
17. Which nutrient keeps us healthy?
18. How often do we need to eat fruit?
19. How often do we need to eat sweets?
20. How often do we need to eat fish?

Build a Digestive System

The digestive systems of humans and bison are adapted to their diet.

Can you reassemble in the proper order the different components of their systems?

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