Somatic and Special Senses
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SOMATIC AND SPECIAL SENSES SPECIAL SENSES 1. 2. 3. 4. 5. Smell Taste Vision Hearing Balance SOMTIC SENSES 1. Tactile (touch) 2. 3. 4. Touch Pressure Thermal (hot vs cold) Pain Proprioceptive SENSORY RECEPTORS Detect environmental changes Sensation occur via a pathway Stimulus Sensory receptor Conduction Integration What integrates the sensation? The brain!!!!! TYPES OF RECEPTORS 1. Mechanoreceptors 2. Nociceptors 3. light Chemoreceptors 5. pain Photoreceptors 4. Touch, pressure, hearing Chemicals in nose and mouth Osmoreceptors Osmotic pressure TYPES OF MECHANORECEPTORS TYPES OF MECHANORECEPTORS Merkel receptors Sense fine detail Fires continuously Meissner corpuscle Control hand grip Fire when stimulus is added and removed TYPES OF MECHANORECEPTORS (CONTINUED) Ruffini corpuscle Senses skin stretching Fire continuously Pacinian corpuscle Respond to fine detail in fingers Fire when stimulus is applied and removed ADAPTATION Sensors adapt by Perception of stimulus fades/disappears “get use to it” HOW SENSITIVE ARE YOU? Measure in mm!! PAIN Fast Pain Slow Pain Localized in large area E.x Why can’t the brain feel pain? Localized E.x Doesn’t have nocicptors http://www.youtube.com/ watch?v=tnABHy6tjL8 HOMUNUCLEUS HOMUNUCLEUS Is a map that corresponds body part to touch sensitivity The proportion of the sensory cortex to the size of the body region is uneven. EX. a relatively large cortical is devoted to the face and the lips, and a small area is devoted to sensations arising from the trunk. MAKE YOUR OWN HOMUNUCLEUS ANALYSIS QUESTIONS 1. 2. 3. 4. 5. 6. Is your skin’s sensitivity in proportion to the size of the body part? Is it reversed? Explain how/why this is the case. What would happen if your skin’s sensitivity in your hands stopped working? Why is a small portion of your cerebral cortex devoted to your arm while a large portion is devoted to your hands and fingers? Which receptors allow you to feel fine detail? Where would you expect to find several of these receptors? Why? Which type of receptors would you expect to find in your fingertips? Why? How different is your homunucleus from your partners? Where are they different and where are they the same? HOMUNUCLEUS ANALYSIS The hands and fingers are more useful for gathering information and need more sensory receptors and area to integrate the info Able to feel fine details with fingers OLFACTION (AKA SENSE OF SMELL) Detected by an olfactory receptor Olfactory receptor Hair like extensions Not nose hair In olfactory epithelium OLFACTORY PATHWAY HTTPS://WWW.YOUTUBE.COM/WATCH?V=SNJNO6OPJCS Odor absorbed by receptor Integrated by limbic system or temporal lobe SMELL AND MEMORY Odor + limbic system + parietal lobe = scent memory TESTING OUR SENSE OF SMELL ANALYSIS 1. 2. 3. How many odors were you able to identify? Were some odors easier to identify than others? Why? Why do you think some odors elicited a memory? HOW SMELL IS INTEGRATED BY THE BRAIN GUSTATION (AKA SENSE OF TASTE) 1. 2. 3. 4. 5. Sour Sweet Bitter Salty Umami (savory/meaty) How does a cold affect your sense of taste? TASTE BUDS (PAPILLAE) On surface of tongue Gustatory Pathway 1. Taste receptors 2. Cranial nerves 3. Medulla oblongata 4. Limbic system 5. Parietal lobe GUSTATORY PATHWAY MAPPING TASTE BUDS Where are the receptors for salt found? sweet ? sour? bitter? savory/umami? The center of the tongue Not many receptors = does sense taste very well HOW THE BRAIN UNDERSTANDS TASTE Neurotransmitter is released Foods taste different because Different neurons are activated ANATOMY OF THE EYE HTTP://WWW.HANDWRITTENTUTORIALS.COM/VIDEOS.PHP?ID=38 FLOW OF TEARS SCIENCE OF TEARS Tears Salt, mucus, lysozyme (kills bacteria) Are produced to: Clear, clean and moisten the eye Emotions LAYERS OF THE EYEBALL 1. Fibrous tunic 2. Vascular tunic 3. Cornea Sclera Choroid Ciliary body iris Retina FIBROUS TUNIC Cornea Is curved This varies in individuals and as you age Sclera “White” of the eye Gives shape Protects Point of muscle attachment VASCULAR TUNIC Choroid Cilliary body Lines the sclera Nourishes the retina Muscle- controls the shape of the lens Process- secretes aqueous humor Aqueous humor Nourishes the eye as it ciculates through both chambers VASCULAR TUNIC Lens Iris Changes shape to focus light on retina Clearer vision Held in place by zonular fibers Is convex (curves outward) Colored part of eye Pupil Light enters here Diameter changes in response to light RETINA (CONTINUED) Fovea centralis Sharp central vision Lots of cones and zero rods Optic disk “blind spot” Does not have photoreceptors (rods and cones) RETINA Photoreceptors Rods Light sensitive cells Transmit info to brain E.x. rods and cones Low light Sense shades of grey Cones Need brighter light Sense color INSIDE THE EYEBALL Vitreous body Fluid that prevents the eye from collapsing Intraocular pressure Refers to fluid inside the eye Balance between production and drainage of aqueous humor RETINA Types of photoreceptors 1. Rods Low light Sense shades of grey 2. Cones Need brighter light Sense color MUSCLES OF THE EYEBALL Ciliary muscle Lateral rectus muscle Moves eye inward Medial rectus muscle Controls diameter of pupil Moves eye outward Orbicularis oculi Open and close the eyelids ANATOMY OF THE EYE ANSWER KEY 2. Fiberous Tunic Cornea and sclera Retina Vascular Tunic Choroid, ciliary body and iris Cones Retina Choroid Lateral rectus muscle Sclera Aqueous Humor Medial rectus muscle Rods Pupil Ciliary muscle Intraocular pressure 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. Cornea Iris Orbicularis oculi Fovea Centralis Pupil Optic nerve Vitreous body, vitreous humor Optic disk Lens Rods and cones Hold the lens in place Superior rectus and inferior rectus True AMOUNT OF LIGHT Bright light Iris expands Pupil gets smaller Low light Iris contracts Pupil bigger . TYPES OF CONES Red cones Sense red light Green cones Sense green light Blue cones Sense blue light THE MANTIS SHRIMP HTTPS://WWW.YOUTUBE.COM/WATCH?V=PPW9RIY7GUS Bullet like punch Punch heats the water to 8,000 F Are able to see cancer Cancer cells scatter light differently It has 16 different photoreceptor cells VISION RATINGS 20/20 20 ft away you see what the avg person sees 20/40 20 ft away you see what the avg person sees from 40 ft away 20/10 20 feet away you see what the avg person sees from 10 ft away VIEWING OBJECTS Distant objects (20 ft away) Light rays are parallel Lens is flat Near objects Light rays are divergent Lens becomes (rounder) =accommodation HOW DOES ACCOMODATION WORK? TESTING THE BLIND SPOT Trial Left Eye Distance Right Eye Distance 1. At what distance did the dot disappear? 2. Why do you think the dot disappeared? 1 2 3 4 5 Average TESTING THE BLIND SPOT Close your right eye. Stand about 20 inches away from the blind spot tester. With your left eye, look at the +. Slowly move toward the image while looking at the +. At a certain distance, the dot will disappear from sight. Measure how far away you were when the dot disappeared. Reverse the process. Close your left eye and look at the dot with your right eye. Move slowly towards the image and the + should disappear. Measure how far away you were when the dot disappeared. TESTING THE BLIND SPOT Measure how far away you were when the dot disappeared. This is when the dot fell on the blind spot of your retina BINOCULAR VISION Allows for Depth 3D vision Better binocular vision Eyes in front TESTING BINOCULAR VISION 1. 2. 3. 4. Have your partner hold two different pencils at different distances in front of you so that both pencils can be seen. With both eyes open, try to grab the pencil that is furthest from you. Repeat steps one and two twice. Have your partner change the pencils distance with each trial Repeat steps one through three with one eye closed THE VISUAL PATHWAY THE VISUAL PATHWAY Images (light rays): 1. Enter the pupil 2. Lens inverts image 3. Optic nerve sends info to the brain ***crosses over at optic chiasm (chi-as-ma) 4. 5. Brain integrates image Sends Info back CERUMEN • Prevents “stuff” from getting into the ear AKA Ear Wax Cerumen CERUMEN FAIL! http://www.youtube.co m/watch?v=ZgLWl1bjH 84 RUPTURED TYMPANIC MEMBRANE What can cause it to tear? Trauma or infection Treatment Self healing May need surgery DID YOU KNOW . . . . . Elephants can hear with their feet! Have pancinian corpuscles in their feet Nerve impulses are sent directly to the brain OUTER EAR Pinna Directs sound waves towards the external auditory canal External auditory canal Funnels sound toward the tympanic membrane MIDDLE EAR Tympanic membrane Auditory Ossicles (bones) Vibrates due to sound waves Deliver sound vibrations Eustanchian Tube Equalizes air pressure Drains middle ear Oval Window Equalizes hydrolic pressure Fluid motion Cochlea Transfers vibrations from ossicles to cochlea Round Window INNER EAR Converts stimuli into nerve impulses Semicircular Canal Equilibrium and balance ANATOMY OF THE EAR ANSWER KEY 11. 3. 4. 5. 6. 7. 8. 9. 10. Oval window Pinna Eustachian tube Delivers vibrations to inner ear fluids Hammer, anvil, stirrup External auditory canal Semicircular canals Round window 12. 13. 14. 15. 16. 17. 18. Tympanic membrane, eardrum Cochlea Repels insects & prevents drying out, earwax To connect with oval window The cochlea To prevents things from getting in The auditory ossicles stapes COCHLEA COCHLEA Basilar membrane Organ of Corti Vibrates in same pattern as sound waves Short hairs = high frequency Longer hairs = low frequency What type of relationship exists between hair length Cochlear Implant and frequency? https://www.youtube.com/watch?v=zeg4qTnYOpw Negative correlation https://www.youtube.com/watch?v=I8eHquhr52s Use of Implant https://www.youtube.com/watch?v=HTzTt1V nHRM BASILAR MEMBRANE VIBRATIONS https://www.youtube.com/watch?v=KnXFlLFsOk PHYSIOLOGY OF HEARING 1. 2. 3. 4. 5. 6. Sound waves enter ear Tympanic membrane pushes auditory ossicles Cause the stapes to “hit” oval window This vibrates fluid in ear Hairs move Nerve impulse sent to brain HEARING AND AGING Hairs in inner ear die or are damaged Do not regenerate
