Brain and Senses. .

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Brain and Senses

Transcript of Brain and Senses. .

Page 1: Brain and Senses. .

Brain and Senses

Page 3: Brain and Senses. .

http://www.city.ac.uk/optometry/Biolabs/Brainlab/Brainlab.htm

AUDITORY

VISIONVISION

SPEECH

Working Memory “Your Minds Blackboard”

SENSORY

MOVEMENT &

BALANCE

Page 4: Brain and Senses. .

http://www.city.ac.uk/optometry/Biolabs/Brainlab/Brainlab.htm

AUDITORY

VISIONVISION

MOVEMENT &

BALANCE

SPEECH

Working Memory “Your Minds Blackboard”

SENSORY

Page 5: Brain and Senses. .

Sense of Sight

Picture From: http://www.newporteyecare.com/graphics/eye_diagram_300x350.jpg

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How You See:• Light waves enter the eye through the

cornea• Pass through the pupil• Pass through the crystalline lens• Light waves are bent by the cornea

and crystalline lens as they pass through

• They converge on a nodal point immediately behind the lens

• At the nodal point the image becomes reversed and inverted

Information and Picture from: http://library.thinkquest.org/05aug/00386/vision/fun/experiment/index.htm

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How You See:• Light waves continue through the vitreous humor to a clear focus on the retina• The small central portion of the retina is called the macula – it provides the best

vision of any location in the retina

Pictures from: http://library.thinkquest.org/05aug/00386/vision/fun/experiment/index.htm and http://www.ghi.com/yourhealth/encyclopedia/articles/color_blindness_basics.html

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How You See:• Rod cells

– more sensitive– responsible for night vision

• Cone cells – responsible for color vision– work best in bright light

Picture from: http://www.colorado.edu/intphys/Class/IPHY3430-200/image/10-35.jpg

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How You See:• Light waves are then changed into

electrical signals• These signals travel through the

optic nerve to the occipital cortex of the brain

• This is where the brain interprets the signals as an image

• Seeing is a collaboration between the eyes and the brain

Picture From: http://www.msstrength.com/wp-content/themes/zen/images/optic_nerve.jpg

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Fun Vision Facts• The eye of a human can distinguish 500 shades of the gray.• The cornea is the only living tissue in the human body that does not

contain any blood vessels.• All babies are color blind when they are born.• A newborn baby sees the world upside down because it takes some

time for the baby's brain to learn to turn the picture right-side up.• Pirates wore earrings because they believed it improved their

eyesight.

Information From: http://www.funshun.com/amazing-facts/eye-human-body-facts.html andhttp://www.drgoldstone2020.com/custom/15/Fun_Eye_Facts.html

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Optical illusions happen when your brain misinterprets signals from your eyes

Picture From: http://blogs.discovermagazine.com/badastronomy/2009/06/24/the-blue-and-the-green/

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Optical illusions happen when your brain misinterprets signals from your eyes

Picture From: http://www.eyetricks.com/0102.htm

Page 13: Brain and Senses. .

Sense of Smell

Picture From: http://www.worsleyschool.net/science/files/nose/page.html

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How You Smell:• Tiny particles from

objects vaporize and enter the nose

• In the nose they are trapped by and dissolve in mucous

• Special cells in the nasal cavity sense these particles

Picture From: http://www.scienceclarified.com/Ro-Sp/Smell.html

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How You Smell:• Olfactory receptor neurons transform

the odor to a chemical message that is sent to the olfactory bulb

• The principle neurons in the olfactory bulb are called mitral cells

• There are about 50,000 of these cells in the olfactory bulb of a human

• From the olfactory bulb, the information is sent to the olfactory cortex

• The information is sent to the amygdala (fear/emotion) and hippocampus (memory)

Picture From: http://bionoid.net/index.php?c=blog&f=itemview&i=3

Page 16: Brain and Senses. .

Fun Smell Facts• Everyone has a unique smell, except for identical twins.• Recall can be enhanced if learning is done in the presence of an

odor and that same odor is present at the time of the recollection.• No two people smell the same odor the same way.• People recall smells with 65% accuracy after a year, while the visual

recall of photos sinks to about 50% after only three months.The average human being is able to recognize approximately 10,000 different odors.

Picture From: http://www.everythingsmells.com/smellyfacts.html http://www.pu-smells.com/educators/funfacts3.html and http://www.senseofsmell.org/funfacts_main.php

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Smell is also plays an important role in taste

Picture From: http://www.tcho.com/chocolate/how-to-taste-chocolate

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Sense of Touch

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Somatosensory(versus Viscerosensory)

•Receptors in skin (over 20 different kinds of nerve endings that send messages to the brain)•Use unipolar neurons (cell bodies in dorsal root ganglia)•Second cell body in spinal cord•Axons cross spinal cord and go to thalamus (relays senses)•In some cases, thalamus sends information to parietal lobe of brain (receives sensory information)

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Brain

Picture from: http://www.coheadquarters.com/coInnerBrain1.htm

Picture from: http://www.braininjury.com/symptoms.html

Page 21: Brain and Senses. .

Touch Receptors

Picture and information from: www.thinkquest.org

•Some areas of your skin are more sensitive than others because they have more receptors•Most sensitive areas of your body are your hands, lips, face, neck, tongue, fingertips and feet•There are about 100 touch receptors in each of your fingertips•More pain nerve endings than any other type•Fun Fact: Rattlesnakes use their skin to feel the body heat of other animals

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Touch

Picture from: http://www.rci.rutgers.edu/~uzwiak/NBSpring11/NBSpringLect3.html

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Touch Experiment/Vocabulary

• Pain receptors most common but you also have receptors that allow you to recognize objects, numbers, letters, etc. by touch

• Inability to recognize objects by touch: asterognosia

• Inability to recognize drawn numbers or letters: agraphesthesia

• Loss of touch/sensation: anesthesia• Loss of pain: analgesia

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Sense of Taste

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Gustatory System•Sensation of taste:

•Salty•Sweet•Bitter•Sour•Umami—detection of natural amino acids and found in meats, cheeses, and broth

•Traditionally, taste was a survival mechanism as many harmful substances taste bitter•Much of the perception of taste is actually mediated by your sense of smell (olfactory neurons)•Must have saliva to taste

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Taste

Picture from: www.wikipedia.org

•Approximately 10,000 taste buds in our mouth (even some on roof of mouth)•Each taste bud had 50-150 receptors•Each receptor responds best to one type of taste•Taste bud receptors are replaced approximately every 7 days•Receptors send information through cranial nerves to part of the brain stem called the nucleus of the solitary tract•Information is then sent to the thalamus and then the cerebral cortex (parietal lobe)•Like smell, taste information also goes to the limbic system (hypothalamus and amygdala)•Also touch receptors on tongue

Information from: http://faculty.washington.edu/chudler/tasty.html and http://library.thinkquest.org/3750/taste/taste.html

Page 27: Brain and Senses. .

Brain

Picture from: http://northofneutral.wordpress.com/2009/11/12/beware-of-amygdala-hijacks/

Picture from: http://www.braininjury.com/symptoms.html

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Fun Taste Facts

• Insects have the most highly developed sense of taste—they have taste organs on their feet, antennae, and mouthparts

• Fish can taste with their fins and tail as well as their mouth

• In general, girls have more taste buds than boys

• Taste is the weakest of the five senses• Inability to taste is called ageusia

Information from: http://library.thinkquest.org/3750/taste/taste.html

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Taste Experiment

• Dry your tongue with a paper towel• Put a saltine cracker on your dry tongue and

see if you can taste it!

Picture from: http://www.thegeminiweb.com/babyboomer/?p=898

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Auditory System•Sound waves funnel into ear through the external ear canal•In the middle ear, the sound waves will cause your eardrum/tympanic membrane to vibrate•Eardrum causes the three smallest bones in your body: the malleus, the incus, and the stapes to vibrate•Vibrations then pass to a coiled tube in the inner ear called the cochlea•The cochlea is fluid filled and contains hair-like nerve endings called cilia•Cilia vibrations are sent to the brain through the auditory nerve to the temporal lobe

Picture and information from: www.thinkquest.org

•The auditory nerve carries information from approximately 25,000 receptors in your ear!

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Brain

Picture from: http://northofneutral.wordpress.com/2009/11/12/beware-of-amygdala-hijacks/

Picture from: http://www.braininjury.com/symptoms.html

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Your Ears and Balance• Near the top of the cochlea are three

loops called the semi-circular canals full of liquid

• When you move your head, the liquid moves and pushes against the hair-like nerve endings

• From these messages, your brain can tell how your body is moving

• If you have ever felt dizzy after having spun around, it was probably because the liquid inside the semicircular canals swirled around inside your ears causing the hair-like projections to move in all different directions sending mixed messages to your brain

Picture from: http://medical-dictionary.thefreedictionary.com/cochlear+canal

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Hearing

Noise Decibels

Whisper 20

Normal Talking 50-60

Car Traffic 70

Alarm Clock 80

Lawn Mower 95

Rock Concert 100

Jackhammer 115

Jet Engine 130

Gun Shot 140

Loudness is measured in decibels

Long-term exposure can cause hearing loss

Pain begins

Short-term exposure can cause hearing loss

Information from: www.thinkquest.org and http://www.gcaudio.com/resources/howtos/loudness.html

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Fun Hearing Facts

• When you go up to high elevations, the change in pressure causes your ears to pop

• Children have more sensitive ears than adults• Dolphins have the best sense of hearing

among animals (14X better than humans)• An earache is caused by too much fluid

putting pressure on your eardrum—often from an infection, allergies or a virus

Information from: www.thinkquest.org

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Hearing Experiment

• Demonstration of how hearing works!

Picture from: http://www.freedomscope.com/wireless_stethoscope_for_the_hearing_impaired.htm