Human Body - Science for Kids - Rock 'N Learn

[Music] rock and learned [Music] hey kevin what are you doing i'm studying for a test over the body i don't see a body it looks like an ordinary book to me no marco i'm learning about the human body that can be a lot of material it is but it's really interesting i'm even considering becoming a doctor or maybe doing medical research wonderful there are so many fascinating jobs in the medical field yeah and learning about the human body is fun i have an idea why don't we join bailey our life science expert on my super

science station to learn more about the human body all right [Music] hi guys welcome to the body systems learning center thanks bailey your body is made up of many different systems here at the body systems learning center we'll take a look at how some of the systems in your body work together to keep you going [Music] your skeletal system keeps you from looking like a bean bag on the floor it's made up of bones that support the rest of your body you should be sure to get plenty of calcium in your diet calcium helps build

and maintain strong bones some bones protect important delicate parts of your body for example this skull is kind of like a helmet inside your head that protects your brain [Music] your brain is the control center for your entire body it's part of the nervous system your nervous system also includes the nerves thin threads of nerve cells called neurons run throughout your body i heard that the nerves carry messages back and forth that's right nerves generally connect to the brain through the spinal cord inside your backbone sensory nerves send messages to the brain from the body

motor nerves carry messages from the brain to all the muscles and glands in your body [Music] exactly and it's your muscular system that allows you to move many of your muscles are attached to your bones with tendons these are called skeletal muscles [Music] but there are other kinds of muscles that help move things inside of you like food or blood isn't blood part of the cert circu circulatory system yeah that one [Music] the circulatory system is an organ system that moves nutrients gases and wastes to and from cells the circulatory system is also called the

cardiovascular system it includes the heart the blood and blood vessels blood is the fluid that circulates around the body bringing to your cells the nutrients and gases your body needs blood also gets rid of the waste your cells produce wow blood is pretty important but wait there's more some cells in the blood help fight diseases and the circulating blood also helps maintain your body temperature the heart is the main engine of the circulatory system it's a large muscle made of four different chambers two on the right and two on the left the right side of

the heart pumps deoxygenated blood into the lungs so that carbon dioxide can be dropped off and oxygen can be picked up the left side of the heart pumps the oxygenated blood all the way to the rest of the body that's why the left side of the heart is bigger than the right it has to work harder are there any other parts of the circulatory system i'm glad you asked the arteries and veins are tube-like vessels arteries take blood from the heart and veins bring blood back to the heart and each time the blood circulates from

the heart out to the body about 20 of it goes through the kidneys the kidneys filter out some of the waste before the blood heads back to the heart the kidneys are actually part of the urinary system [Music] the urinary system removes waste from the blood converts it to urine and stores it until it's tinkle time the kidneys are two bean-shaped organs they filter waste called urea from the blood they combine the urea with extra water from the body to produce urine then the urine passes down two thin tubes called ureters to the bladder the

bladder is a hollow balloon shaped organ that holds the urine until it's time to go to the bathroom then the urine passes out a small tube called the urethra and out of your body and then you can breathe easy you sure can with your lungs which are part of the respiratory system [Music] the respiratory system allows oxygen into the blood and lets carbon dioxide leave the blood that sounds simple enough but let's go through all the parts of the respiratory system so we can understand how it works this large muscle attached to the lungs is

called the diaphragm when it contracts the lungs pull in air and you take a breath air enters through the nose into the nasal cavity as it flows through the nasal passages the air gets filtered warmed and moistened mucus along these passages trips dust and particles in the air to clean it before it gets to the lungs after the nasal passages the air travels past the larynx or voice box then the air moves down the trachea or windpipe the trachea joins the upper respiratory tract to the lungs if you gently touch the front of your throat

you can feel the trachea nice marco your description of the upper respiratory system is like a breath of fresh air but let me tell you what happens once the air gets into the lungs at the bottom of the trachea are two large tubes these tubes are called the main stem bronchi one goes into the left lung and the other goes into the right lung each main stem bronchus then branches off into tubes or bronchi they get smaller and smaller like branches on a tree the tiniest tubes are called bronchioles and there are about 30 000

of them in each lung each bronchiole is about the same thickness as a hair at the end of each bronchiole is a special area that leads into clumps of tiny air sacs called alveoli there are about 500 million alveoli in your lungs each alveolus has a net like covering of small blood vessels called capillaries these capillaries are so tiny that the cells in your blood need to line up single file just to get through them whoa capillaries are really tiny yes they are the alveolus is the pickup place for oxygen which the cells in your

body need to work and they're also the drop-off place for carbon dioxide which is a waste product from your cells hey that's the exact opposite of what plants do smart boy i like it the way you think your lungs are important for breathing but they are also important for talking which i just love to do we know marco above the trachea is the larynx or voice box across the voice box are two pieces of tissue called vocal cords when the vocal cords are open air flows through freely when they partially close as you exhale they

vibrate to make sounds hey that's pretty cool sounds like your tummy wants to talk i guess i'm a little hungry perfecto let's talk about the digestive system while you eat this orange we'll talk about where that orange will travel as it makes its way through your digestive system your body actually gets ready for digestion before you eat just seeing or smelling food creates saliva or spit in your mouth when you eat food the saliva breaks down the chemicals in the food a little your tongue helps out too pushing the food around while you chew with

your teeth when you're ready to swallow the tongue pushes the mushed up food toward the back of your throat and into the opening of your esophagus the second part of the digestive tract the esophagus is a stretchy pipe that's about 10 inches long it moves food from the back of your throat to your stomach when you swallow a special flap called the epiglottis flops down over the opening of your windpipe to make sure the food enters the esophagus and not the windpipe muscles in the walls of the esophagus move in a wavy motion to slowly

squeeze the food through the esophagus this takes about two or three seconds your stomach is attached to the end of the esophagus it's a stretchy sac shaped sort of like the letter j it has three important jobs to store the food you've eaten to break down the food into a bulky liquid mixture and to slowly empty that liquid mixture into the small intestine the stomach is like a mixer churning and mashing together all the small balls of food that come down the esophagus into smaller and smaller pieces it does this with help from the strong

muscles in the walls of the stomach and gastric juices that also come from the stomach's walls in addition to breaking down food gastric juices also help kill bacteria that might be in the food this small intestine is a long tube with about a one inch diameter it's packed inside you beneath your stomach and a dog's small intestine is about 22 feet long the small intestine breaks down the food mixture even more so your body can absorb all the vitamins minerals proteins carbohydrates and fats the small intestine can help extract these nutrients with a little help

from the pancreas liver and gallbladder those organs send different fluids to the first part of the small intestine these juices help to digest food and allow the body to absorb nutrients the pancreas makes enzymes that help the body digest fats and protein a fluid from the liver called bile helps to absorb fats into the bloodstream and the gallbladder serves as a warehouse for bile storing it until the body needs it food may spend as long as four hours in the small intestine during that time the food becomes a very thin watery mixture nutrients in the

food are absorbed into the blood and go to the liver the leftover waste or the part of the food your body can't use goes on to the large intestine the nutrient-rich blood comes directly to the liver for processing the liver filters out harmful substances or wastes and turns some of the waste into more bile the liver even helps figure out how many nutrients will go to the rest of the body and how many will stay behind in storage for example the liver can store certain vitamins and a type of sugar your body uses for energy

[Music] at about 2.5 inches across the large intestine is thicker than the small intestine and it's almost the last stop on the digestive tract like the small intestine it is packed into the body and would measure five feet long if you spread it out let's not try that the waste passes through the part of the large intestine called the colon which is where the body gets its last chance to absorb the water and some minerals into the blood as the water leaves the waste product what's left gets smaller and harder as it keeps moving along

until it becomes a solid the large intestine pushes the waste into the rectum the very last stop on the digestive tract the solid waste stays here until you are ready to push it out wow that's a lot of information to learn i think i can make it a little easier to digest [Music] let's go [Music] [Applause] the alimentary canal that's another name for the digestive system i'm not so sure about this don't worry it'll be fun and here's some music you can really sink your teeth into ladies and gentlemen they're rocking mullers yeah let's travel

through the aloe mountain now [Music] [Music] your tongue pushes it back after it is chewed the epiglottis comes next for us it helps food go down the esophagus and not down the wind pipe next comes the stomach the food goes in and it's broken down before the small intestine the blood picks up some nutrients there and takes them to the liver to store and share awesome then comes the large intestine for waste accumulation it takes out more water and gets things ready for defecation waste moves through the colon getting hotter as it flows till finally

out of the rectum it goes wow that was fun we're not finished yet [Applause] that's all of the body systems we have time for now step right this way what's this place it's this sensory learning center this stuff looks cool this stuff is cool it will help us learn about your five senses sight taste smell hearing and touch from the moment you wake up in the morning until you go to bed at night your eyes take in information and relay to your brain for interpretation when you look at an object you are actually seeing the

light that bounces off the object and into your eyes the light enters your eye through this transparent protective layer called the cornea then light passes through the dark round opening in the center of your eye called the pupil i've noticed in the mirror that sometimes my pupils are large and sometimes they get smaller that's because of the muscles in the iris or the colored part of the eye by expanding and contracting the iris can change the size of the pupil according to the amount of light that's around you when you're in bright light the iris

expands and the pupil becomes smaller ah but if it's dark the iris makes the pupil larger to let in more light you've got it the muscles of the iris adjust the size of the pupil and determine how much light enters the eye just behind the pupil is the lens with the help of muscles the lens actually changes shape to bring things into focus if you're looking at something up close the lens will become thicker but if you are admiring something far away the muscles will squeeze the lens to make it thinner so that you can

see the image clearly i get it the muscles around the lens of my eye kind of act like the automatic focus of a camera exactly after the lens the image travels through the vitreous humor no not that kind of humor the vitreous humor or just vitreous is a jelly-like substance that fills your eye the light travels through it onto the back surface of the eyeball called the retina the retina has over 100 million light-sensitive cells called rods and cones rods identify shapes and work best in dim light they aren't very good at detecting color cones

on the other hand identify color and fine details they work best in bright light both of these types of cells send information to the brain through the optic nerve the amazing thing is that when images go through the lens they are turned upside down it's the brain's job to turn the image right side up and then tell you what you are seeing the brain does this in a special place called the visual cortex because your eyes are so important they have many features to protect them the eyebrows help block sweat from running into your eyes

eyelashes help keep out small dirt and dust particles and eyelashes also protect your eyes from sunlight or bright lights your eyelids sweep dirt from the surface of the eye when you blink and they help protect your eyes from injury tears constantly bathe the front of your eye to keep it clean and moist i think i see how important the eyes are let's move on to the sense of taste there are four main taste sensations sweet salty sour and bitter but some experts add a fifth called umami or savory most of the receptor cells for taste

in humans are found on the surface of the tongue and along the soft palate some people used to think that different parts of the tongue could only detect certain tastes but scientists now know that any taste sensation can come from any area of the tongue most of your sense of taste is really about your sense of smell huh what marco is trying to say is that most of the time when you think something is delicious it is because you like it smell you're smelling food not only before you take a bite but also while you

are chewing odor molecules from the food inside your mouth float upwards on a remarkable smell journey special cells in your nose recognize tiny odor particles floating in the air these molecules can come from things like food or flowers or even stinky things many odors aren't single sense or single kinds of molecules but a mixture of different things as you breathe in air passes through the nasal cavity i remember that's where the air gets filtered warmed and moistened right the odor chemicals that you inhale reach an area on the roof of your nasal cavity called the

olfactory epithelium it's covered with millions of microscopic nerve cells that can detect smell these nerve cells connect into the olfactory nerve which takes smells to the olfactory cortex in your brain if your nose is at its best and you don't have a cold you can tell the difference between as many as 10 000 different smells that's amazing it certainly is hey when talking about our sense of smell i noticed the word olfactory several times good observation kevin olfactory is a useful vocabulary word olfactory means related to the sense of smell now let's talk about how

your ears work when an object makes a noise it sends vibrations speeding through the air those vibrations are also known as sound waves your outer ear funnels these vibrations into your ear canal as the vibrations move into your middle ear they hit your eardrum and cause it to vibrate the eardrum is also called the tympanum it is smaller and thinner than the nail on your pinky finger that is small when your eardrum vibrates it passes along the sound vibrations to the three smallest bones in your body the hammer then the anvil and finally the stirrup

this stirrup passes the vibrations into a coiled tube in the inner ear called the cochlea the fluid-filled cochlea contains thousands of hair-like nerve endings called cilia when the stirrup makes the fluid in the cochlea vibrate the cilia move if destroyed by loud sounds these cilia never grow back so that's why my mom doesn't want me listening to loud music right different cilia are specialized to detect sounds at various frequencies they send this information to the brain through the auditory nerve your brain makes sense of the messages and tells you what sounds you are hearing your

ears also help you keep balance near the top of the cochlea are three loops called the semicircular canals these fluid field loops are pointed upward diagonally and horizontally when you move your head the liquid in the semicircular canals moves around it pushes against hair-like nerve endings which send messages to your brain from these messages your brain can tell how your body is moving if you have ever felt dizzy after riding a carnival ride that spins it was probably because the liquid inside these semi-circular canals swirled around inside your ears this made the hairs of the

sensory cells bend in all different directions and send confusing signals to your brain oops that made me feel a little dizzy made you feel huh then why don't we talk about a different kind of feel your sense of touch your skin is the largest sensory organ of the body the most common types of receptors found in your skin are heat cold pain pressure and touch many people think of pain as being bad but pain receptors actually help keep you safe by telling your brain that a part of your body is being harmed this is probably

the reason we have more nerve endings for pain than any other type have you ever noticed that some parts of your body are more sensitive than others yeah even a tiny paper cut on my finger can be really painful that's because there are more receptors in some areas of your skin than in others the more receptors the more sensitivity some of the most sensitive areas of your body are your hands lips face neck tongue fingertips and feet and the least sensitive part of your body is the middle of your back thanks guys i've learned a

lot about the human body today we'll see about that let's play the body wheel [Applause] you folks at home can play along to see how much you have learned let's get started spin that wheel kevin okay here goes [Music] ah the circulatory system read the question bailey how many chambers are found in the human heart four you are correct sir blood flows into the right atrium and then the right ventricle pumps it to the lungs after picking up oxygen the blood returns to the left atrium and the left ventricle pumps the oxygenated blood to the

rest of the body you have 1 000 points kevin spin again [Music] don't be nervous just kidding i know you'll do well with this question on the nervous system what kinds of nerves send messages to your brain from your body hmm there were the sensory nerves and the motor nerves because the body has sensory receptors that send messages to your brain i'll have to say it's the sensory nerves fantastico you remembered both kinds of nerves and the sensory nerves really are the ones that send messages to your brain that's another thousand points for you do

i get to spin again you certainly do [Music] this is not my strong suit can i buy a bowel read kevin his question about the muscular system bailey what kinds of muscles help you move i know this one the skeletal muscles perfecto the skeletal muscles can move from involuntary reflexes but they usually act as voluntary muscles that means you move them by thinking about them but smooth muscles are involuntary examples of smooth muscles are the muscles that move food in your stomach and intestines muscles that make your blood vessels larger or smaller and do you

remember those small circular muscles in your eye the iris yes that's it another kind of involuntary muscle is the cardiac muscle which is only found in the walls of the heart you have 3 000 points kevin this is your last spin i hope it's a good one [Music] ah what a breath of fresh air bailey the question please this one's worth 2 000 points what structures in the lungs take oxygen into the capillaries i remember this the alveoli that's right the alveoli are the tiny air pockets where oxygen is exchanged for carbon dioxide hooray you

have 5 000 points you win what do i win what do i win a trip oh boy where do i get to go a trip home [Music] don't be disappointed this is a trip in style [Music] [Applause] this is awesome where do i get on the spaceship spaceship there's no spaceship [Music] uh what now [Music] hello everyone mike mechanical your friendly mechanical pencil here let's look at some questions about the human body with marco kevin and bailey you might see some questions like these on a life science test if you like you can download a

copy of the test at marco's website marcothepencil.com let's get started one in which order does food travel through the digestive system after it is swallowed b looks correct but i better read the other answers just to make sure a is not correct the trachea is part of the respiratory system you don't breathe your food not unless you want to get choked c is wrong too no way does the stomach come before the esophagus and d has trachea in the list again so our answer is b esophagus stomach small intestine large intestine [Music] [Applause] i like

the way you are carefully examining each answer before making your choice thanks marco two which best describes the primary role of the lungs in the respiratory system a the lungs exchange carbon dioxide for oxygen that is an important role of the lungs but i'll look at the other choices to be sure this is the best answer b the lungs are necessary for people to talk hmm that's true but it doesn't seem like the primary or most important role of the lungs nope how about c the lungs house the bronchioles and the diaphragm hold on the

diaphragm isn't inside the lungs this one is wrong that means d all of the above can't be right our best answer is a [Music] [Applause] three which system is responsible for transporting nutrients gases and wastes to and from the cells in the body let's see all of these systems move things around in the body but the only one that actually transports nutrients to the cells and takes gases and wastes away from the cells would have to be the circulatory system it includes the heart the blood and the blood vessels sounds like a is that answered

[Music] [Applause] you are so smart kevin let's quickly review these other systems in the question the respiratory system helps exchange gases to support life in humans and other mammals this provides oxygen to the blood and removes carbon dioxide and other gaseous wastes from the blood the digestive system turns the food you eat into useful nutrients and the urinary system you may recall produces stores and eliminates urine bailey you're kind of showing off don't you think why thank you marco why don't you read the next question kevin four jackson broke his arm playing soccer what conclusion

can jackson make from the bar graph below oh boy a graph question yeah we see a lot of those in my class and sometimes they can be a little confusing i will help you through it what do you notice right off it looks like they're comparing the amount of calcium in some food servings is there anything you notice about the bars a cup of plain yogurt is way above the other foods for the percentage of daily calcium that it provides although swiss cheese is not too far behind hey bailey told me that calcium is important

to build and maintain strong bones that means it would probably help repair a broken bone it sure would now read the answers to find the best conclusion about the graph a he should avoid yogurt so that his arm will have a better chance of healing no way that would be the opposite of what jackson would want a void means that you don't do it b swiss cheese would be a better choice than yogurt to provide more calcium no the graph shows that swiss cheese has less calcium than yogurt even though swiss cheese has more calcium

per serving than some of the other foods [Music] yogurt would be the best choice to get the most calcium that sounds right but let me read the last answer just to make sure reading all of the answers is always a good test-taking strategy d jackson should avoid pinto beans and broccoli oh no marco no i'm confused should jackson avoid those foods since he needs lots of calcium are you saying he should just eat yogurt all the time no that would get boring besides it wouldn't be healthy to only eat yogurt even though it's not my

favorite food i eat broccoli because it provides lots of healthy nutrients like vitamins and antioxidants and pinto beans have protein and fiber jackson wouldn't want to avoid broccoli or pinto beans necessarily i'll stick with answer choice c magnifico [Music] [Applause] i like the way you use good reasoning to arrive at your answer and you considered all of the choices all right that was fun for more great learning adventures you can visit my buddy marco's website www.markothepencil.com see you later you