FORM 2The world through our senses
1.Sensory organsSensory organsType of sensesStimuli detectedSkinTouchTouch, temperature,pressure, painNoseSmellChemical in air TongueTasteChemical in foodEarHearingSoundEyeSight Light2.Pathway from stimulus to responseStimulus → receptors→ nerves → brain →nerves → effectors → response3.Sense of touch is the sense that is sensitive towards the touch pain,pressure, cold and heat.4.The skin of human is divided into two layers, dermis and epidermis.5.Types of receptors :–Pain receptor–Heat receptor–Pressure receptor–Cold receptor–Touch receptor1.Sensitivity of skin depends of two factors:–Thickness of the epidermis–Number of receptors1.Sense of smell is the sense that can detect stimuli produced bychemicals.2.The sensitivity of nose depends of two factors:–The strength of the smell–The presence of mucus1.The sense of taste is the sense that can detect stimulus produced byflavoured chemicals.2.The tongue is the sensory organ for taste.3.The tongue enables us to detect sweet, salty, sour, and bitter.4.The surface has many taste buds.5.The sense of hearing is the sense that can detect source of soundproduced by vibrating object.6.The function of each part of the eara)Pinna – collects and directs sound wave into ear canalb)Ear canal – directs sound waves to the eardrum