The five senses
Vocabulary
Index
Word
Spanish
Regular
Slow
Display
Display
#TEXT
Dalay time:
Pause
Translate
Selected and not selected words
Show me words On
Show me words Off
Index
Word
Spanish
Transcript
Regular audio
Slow audio
+ 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 (of sound) 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 it 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 older 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. - The 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. + Whoops 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.
Escuela de Arte y Tecnología