T HE S ENSORY S YSTEM By: Colin, Haley, Connor, Crystal, Abby, and Derek

V OCABULARY Retina- A layer of light-sensitive cells in the back of the eye Rods-photoreceptors that detect very dim light Cones- photoreceptors that detect bright light and help you see colors Iris- the colored part of the eye

V OCAB CONT. Lens- a curved, transparent object that forms an image by refracting light Pupil- a hole in the eye which light enters through Cochlea- an organ in the ear that converts sound waves into electrical impulses Taste buds- Receptors for tasting

N OSE The nose is one of the five senses. The nose helps you to smell good and bad smells. Smell and taste are closely related. The receptors for smelling are olfactory cells. When you inhale through your nose it filters and warms the air. The receptors for smell are located on olfactory cells in the upper part of your nasal cavity.

T HE E AR Has the three smallest bones in the body Made up of three parts Outer (Pinna)- Channels sound into middle ear Middle- Eardrum, the 3 bones Inner- Cochlea, waves create vibrations there Cochlea has two purposes 1) Keeps you balanced 2) Converts waves into vibrations The Auditory Nerve sends the vibrations to the brain. The Eardrum vibrates and makes the bones vibrate.

T HE E AR The ear is composed of many parts that if we were to loose any of the following parts you would not be able to hear as well as you could. The parts of the ear are: auricle, outer ear canal, eardrum, malleus, incus, stirrup, cochlea, and the auditory nerve. Outer ear is composed of the auricle and outer ear canal Middle ear is composed of the eardrum, malleus, incus, and stirrup Inner ear is composed of the cochlea and the auditory nerve The cochlea and the auditory nerve could be the most important parts of the ear. The cochlea converts sound waves into electrical impulses and sends them to the auditory nerve. The auditory nerve then sends it to the brain, and the brain interprets them. The malleus, incus, and stirrup are the smallest bone in the body which is incredible for the job they perform A very important part of the ear also is that the ear helps keep the body balanced When you spin around in circles the reason why you get dizzy is because the fluid in the cochlea is moving around making everything spin

T HEEYE T HE EYE The second most complex organ. The eye can see a candle up to 14 miles in the right conditions. There are 120,000,000 rods for night vision. When there is an object coming toward you, your eye will automatically blink so it doesn’t damage your eye. The tears are meant to clean the eye, and is very helpful to heal cuts or scratches in your eye. There are 2,000,000 working parts in the eye. The eye can process 36,000 bit of information every hour. The human eye weighs approximately 28 grams. Sight is the ability of the brain and the eye to work together to detect light waves within the visible range which is sight. The second most complex organ. The eye can see a candle up to 14 miles in the right conditions. There are 120,000,000 rods for night vision. When there is an object coming toward you, your eye will automatically blink so it doesn’t damage your eye. The tears are meant to clean the eye, and is very helpful to heal cuts or scratches in your eye. There are 2,000,000 working parts in the eye. The eye can process 36,000 bit of information every hour. The human eye weighs approximately 28 grams. Sight is the ability of the brain and the eye to work together to detect light waves within the visible range which is sight.

T HE E YE The light enters the eye through the pupil. It passes through the lens. The lens changes the shape and the direction. Light energy produces changes in photoreceptors that trigger nerve impulses. The image “hits” the retina and sent to the optic nerve. From the optic nerve the image is sent to the brain.

The tongue is a very interesting organ It is part of the sensory system On the tongue, there are thousands of tiny little bumps called papillae. Embedded in the papillae, are the very tiny taste buds. The taste buds are the things that sense the taste of everything you eat or drink. After the taste buds receive the taste of something, it sends a signal through several nerve cords, and then proceeds to the brain, all in a fraction of a second. All instantaneously, that is the sense of taste Sensory receptors in your tongue detect dissolved chemicals.

F UN F ACTS A elephant nose can smell water three miles away. Insects have the most powerful sense of taste. The carrot only seems orange because they reflect only orange light. Girls usually have more taste buds than boys. Your eyes are the same size from birth, but your nose and ears are always growing. You can recognize about 10,000 different odors. Your thumb is the same length as your nose.