The senses
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Transcript of The senses
The SensesThe Senses
Chapter 8.2Chapter 8.2
How Does Vision Occur?How Does Vision Occur?
PathwayPathway
Light enters through pupilLight enters through pupil Lens focuses light on retinaLens focuses light on retina
PhotoreceptorsPhotoreceptors RodsRods
Night visionNight vision 75 – 150 million75 – 150 million Not color sensitiveNot color sensitive
ConesCones Require more lightRequire more light Best for daytimeBest for daytime 6/7 million6/7 million Sensitive to colorSensitive to color
Light energy changes into neuronal impulsesLight energy changes into neuronal impulses Optic nerve carries impulses from retina to the brainOptic nerve carries impulses from retina to the brain
Binocular FusionBinocular Fusion
Images received from two eyes into a Images received from two eyes into a single imagesingle image Retinal disparity is the difference between the Retinal disparity is the difference between the
images stimulating each eyeimages stimulating each eye
How Do We Hear?How Do We Hear?
Pathway of SoundPathway of Sound
Outer ear receives soundOuter ear receives sound Earflap directs sound down the auditory canalEarflap directs sound down the auditory canal Vibrations occur in the canal and vibrate the eardrumVibrations occur in the canal and vibrate the eardrum Middle ear is filled with 3 tiny bones (hammer, anvil, Middle ear is filled with 3 tiny bones (hammer, anvil,
stirrup)stirrup) Vibrates and pushes against the cochleaVibrates and pushes against the cochlea Inner ear= cochleaInner ear= cochlea
Contains fluids and neuronsContains fluids and neurons Pressure causes liquid to move hairs which are attached to Pressure causes liquid to move hairs which are attached to
sensory cells that pick up the motion and turn it into sensory cells that pick up the motion and turn it into neuronal impulsesneuronal impulses
Auditory nerve carries impulses to the brain (temporal lobe)Auditory nerve carries impulses to the brain (temporal lobe)
DeafnessDeafness
Conduction DeafnessConduction Deafness Hinders physical motion through rigidness Hinders physical motion through rigidness
of outer/middle ear bonesof outer/middle ear bones Hearing aids can helpHearing aids can help
Sensorineural DeafnessSensorineural Deafness Damaged cochlea, hair cells, or auditory Damaged cochlea, hair cells, or auditory
neuronsneurons Hearing aids don’t help, cochlear implant Hearing aids don’t help, cochlear implant
mightmight
Vestibular systemVestibular system
Regulates balanceRegulates balance PathwayPathway
3 semicircular canals provide the sense of 3 semicircular canals provide the sense of balance, located in the inner ear and balance, located in the inner ear and connected to the brain by a nerveconnected to the brain by a nerve
Hair cells project into the fluid in the canalHair cells project into the fluid in the canal When you move, canals move, and inertia When you move, canals move, and inertia
causes the fluid to move which bends the causes the fluid to move which bends the receptor cells that are in the fluidreceptor cells that are in the fluid
Over stimulated – causes dizzinessOver stimulated – causes dizziness
Chemical SensesChemical Senses
SmellSmell Vapors enter nose and come into contact with a Vapors enter nose and come into contact with a
special membrane w/ receptors in the upper nosespecial membrane w/ receptors in the upper nose Receptors send messages about smell through the Receptors send messages about smell through the
olfactory nerve olfactory nerve TasteTaste
Chemicals stimulate receptors on the taste budsChemicals stimulate receptors on the taste buds Taste, texture, and temperature info are relayed Taste, texture, and temperature info are relayed
to brainto brain
TouchTouch
Provides information on: Pressure, Provides information on: Pressure, warm, cold, and painwarm, cold, and pain
The more receptors the more sensitiveThe more receptors the more sensitive Skin is sensitive to temperature, but it Skin is sensitive to temperature, but it
has to be different than that of the skinhas to be different than that of the skin Pain is a warning sign to prevent Pain is a warning sign to prevent
damagedamage
Perceptions of PainPerceptions of Pain
Results fromResults from Intense pressureIntense pressure LightLight NoisesNoises HeatHeat
Two typesTwo types Sharp localized painSharp localized pain
What you feel immediatelyWhat you feel immediately Dull generalized painDull generalized pain
Pain you feel laterPain you feel later
Gate Control Theory of Pain Gate Control Theory of Pain
Lesson the pain by shifting our Lesson the pain by shifting our attention away from the pain attention away from the pain impulsesimpulses
Send other signals to compete with Send other signals to compete with the pain signalsthe pain signals
The gate limits the number of The gate limits the number of impulses that can be transmittedimpulses that can be transmitted Athletes can finish a game injuredAthletes can finish a game injured
KinesthesisKinesthesis
The sense of movement and body The sense of movement and body positionposition Works together with vestibular and Works together with vestibular and
visual senses for posture and balancevisual senses for posture and balance Comes from receptors of muscles and Comes from receptors of muscles and
tendons, and jointstendons, and joints No kinesthetic sensation, movements No kinesthetic sensation, movements
would be jerky and uncoordinatedwould be jerky and uncoordinated