1. Sensory Receptors

3. D.S.Q. 1. What is getting ready to happen to the foot in the picture? 2. What will most likely happen as soon as the feather rubs against the foot? 3. What causes different reactions to this kind of stimulation?

4. Discussion Questions 1. How many senses do we have? 2. When we sense something by touch, our bodies receive a mechanical input. What kind of input are we receiving with our sense of taste or smell? Chemical input 3. What kind of input are we receiving with our sense of sight or hearing? Electromagnetic Input 4. What allows us to hear a sound?

5. How do we receive signals? Which system helps us receive signals? Nervous system Any change or signal in the environment that an organism can recognize and react to is called a stimulus. After the nervous system analyzes a stimulus, it directs a response.

6. What do our senses do? Your eyes, ears, nose, mouth and skin are specialized sense organs that enable us to get information from the outside world. Each organ contains sensory neurons that send impulses to the brain Your brain interprets them, which enables us to understand more about the environment.

7. How do we see? Our eyes respond to the stimulus of light WE convert that stimulus into impulses that our brain interprets, which lets us see First, the light rays enter through the pupil Second, they pass through the lens and the muscles in the lenses adjust the shape and focus the light rays on the retina Third, the lens bend the light rays, and produce an upside down image

8. How do we see cont.? Fourth, the nerve impulses then travel through the brain and the brain turns the image right-side up

9. Taste and Smell Taste and smell work together They both depend on chemicals in the air or in food The chemicals trigger responses in receptors in the nose and mouth Then the nerve impulses travel to the brain and helps us interpret the smells and tastes

10. How do we hear? Sounds are caused by the vibrations of air particles Ears convert sound waves into nerve impulses that your body interprets 3 main parts of the ear—outer,middle, & inner

11. How do we hear cont? 1. Sound waves enter your outer eat through the canal 2. When the sound waves reach your eardrum, they cause it to vibrate 3. The vibrations pass the 3 tiny bones in the middle of your ear, and takes them to the inner ear. 4. These vibrations turn into nerve impulses and then are interpreted by the brain

12. Touch Sense of touch is found all over your skin.

13. 4 types of nerves that respond to specific kinds of changes 1. Mechanical Changes (Mechanoreceptors) Enables us to detect touch, sense the position of our muscles, bones and joints and detect sounds and the motion of the body

14. 4 types of nerves that respond to specific kinds of changes 2. Chemical Changes (Chemoreceptors) The chemical processes of smelling and tasting begins when molecules go into the nose or mouth where they dissolve and stimulate special chemical receptor cells. The cells then send the messages to the brain and that detects the odors and flavors.

15. 4 types of nerves that respond to specific kinds of changes 3. Temperature Changes (Thermoreceptors) Humans and animals sense hot and cold temperatures on their skin and inside their bodies Thermoreceptors are in the brain and are used to monitor internal body temperatures

16. 4 types of nerves that respond to specific kinds of changes 4. Light Changes (Photoreceptors) Eyes are the only organs that detect light using different receptors in the retina for color (cones) and brightness (rods)