NATURAL SCIENCES 3 UNIT 3 OUR SYSTEMS LIFE PROCESSES AND SYSTEMS LIFE PROCESSES NUTRITION INTERACTION REPRODUCTION ü Digestive system ü Circulatory system ü The senses ü Nervous system ü Reproductive system ü Respiratory system ü Excretory system ü Locomotor system Commented [A1]:
THE SENSES We use our senses, our locomotor system and our nervous system to interact with the world. We have five senses: sight, hearing, smell, taste and touch. HOW IT WORKS Each of our senses sends a message through the nervous system to our brain so we know what is happening around us and can respond.
1. SENSE OF SIGHT Ø Our eyes are the organs of sight. Ø We can identify different shapes, sizes, colours and distance. Ø Parts of our eyes: a) The iris is a big coloured circle at the front of the eye. b) The pupil is a black circle in the middle of the iris. c) The retina sends information to our brain through the optic nerve. How we see 1. Light enters the eye through the pupil. 2. The retina sends information to our brain through the optic nerve. 3. Our brain identifies the image.
TAKE CARE OF YOUR EYES 1. Visit the optitian s regularly. 2. Wear glasses if you need them. 3. Always read with good light. 4. Don t spend too long using a computer. 5. Don t sit too near the televisión. Watch: HOW OUR EYES WORK https://www.youtube.com/watch?v=syaqgmxb5i0
2. SENSE OF HEARING Ø The ears are the organs of hearing. Ø We can identify loud high and low sounds., quiet Ø Parts of the ears a) Outer ear: It s made up of the part of the ear that is visible and the ear canal. b) Middle ear: It s made up of the ear drum and the three small bones. c) Inner ear: It s made up of the cochlea and the auditory nerve. Outer ear Middle ear Inner ear
HOW WE HEAR 1. Sounds enter the outer ear and go into the middle ear. 2. They make the eardrum vibrate. 3. The vibrations travel along the three small bones to the cochlea. 4. The auditory nerve carries the signals to the brain. TAKE CARE OF YOUR EARS 1. Keep your ears clean by washing them. 2. Stop using cotton swabs in your ears. 3. Keep your ears dry. 4. Turn the volumen down. 5. Use ear plugs around loud noises. Watch: How your ears work https://www.youtube.com/watch?v=hmxohkwwmu8 Play: Identify the sounds http://www.scholastic.com/magicschoolbus/games/sound/
3. SENSE OF SMELL Ø Our nose is the organ of smell. Ø We can identify good and bad smells. Ø Parts of the nose a) The nostrils: they are two holes in your nose. b) The olfactory nerve: it is responsible for your sense of smell. It detects smells in the air and transmite the information to your brain. olfactory nerve nostril HOW WE SMELL 1. Air enters the nose through the nostrils. 2. Air goes to the olfactory nerve. 3. The olfactory nerve detects smells in the air. 4. It sends the information to our brain.
TAKE CARE OF YOUR NOSE 1. Keep your room clean. 2. Blow your nose when it s blocked with a clean tissue. 3. Don t put things into your nose. 4. Cover your mouth with a tissue when you sneeze or cough. 5. Avoid inhaling smoke. Watch: How your nose works https://www.youtube.com/watch?v=hzoszx_hxe4 4. SENSE OF TASTE Ø Our tongue is the organ of taste. Ø We can identify different tastes: salty, sweet bitter and sour. Ø Our tongue is covered in many taste buds. tongue taste buds
HOW WE TASTE 1. Taste buds identify different tastes. 2. Nerves send information about the different tastes to our brain. TAKE CARE OF YOUR SENSE OF TASTE 1. Wash your hands before your eat. 2. Brush your teeth three times a day. 3. Visit the dentist regularly. Watch: How your tongue Works https://www.youtube.com/watch?v=0hwol91cjwm 5. SENSE OF TOUCH Ø Our skin is the organ of touch. Ø Our body is covered in skin. Ø We can identify things that are hot, cold, soft, hard, rough or smooth.. Ø Our skin has lots of nerve endings. nerve endings
HOW WE FEEL 1. You feel sensations through the nerve endings in the skin. 2. Nerves send this information to our brain. TAKE CARE OF YOUR SKIN 1. Keep your skin clean. 2. Protect your skin from sunlight. 3. Wear appropiate clothing. Watch: How your skin works https://www.youtube.com/watch?v=amggcxuyxt8