SCF3C1_Eye_Ear_Nose PDF

Eyes and the Sense of Sight 1. The eye is the sensory organ sensitive to light. 2. We can see the beautiful things around us because we have eyes to detect lights of different colours. 3. The wall of the pupil eyeball consists of three layers: Sclera (outer layer) Choroid (middle layer...

Eyes and the Sense of Sight 1. The eye is the sensory organ sensitive to light. 2. We can see the beautiful things around us because we have eyes to detect lights of different colours. 3. The wall of the pupil eyeball consists of three layers: Sclera (outer layer) Choroid (middle layer) Retina (innermost layer) 4. How do we see? The flowchart below will show you how we are able to see the things around us. Ear and the Sense of Hearing 1. Ear is a sensory organ that detects sounds and gives us the sense of hearing. 2. We hear hundreds of different sounds each day. 3. The human ear is divided into 3 major sections: Outer ear, middle ear and inner ear 4. How exactly do we hear sounds? The flowchart below will show you the mechanism of hearing. 5. As a person grows older, their sense of hearing will be weaker. 6. This could be due to the eardrums becoming less elastic so it cannot vibrate as well as it used to. Nose and the Sense of Smell 1. There are thousands of chemicals in the air that we breathe in each day. 2. Some of these chemicals, when dissolve in the mucus on our smell receptors in the nose, will enable us to smell. 3. The nose is a sensory organ that is sensitive to smell. 4. Besides being a sensory organ, the nose also allow air to pass through it to enter our lungs for respiration. 5. There are hairs in the nose that traps dust and microorganisms. 6. How do we smell? The flowchart below shows the mechanism of smell. 7. Have you ever wondered why we cannot smell properly when we have a cold or flu? 8. When we have flu, too much mucus on the smell receptors will prevent the receptors from detecting the chemicals as air flows through.