Title: Some on the eye
1Some on the eye
- Myopia Near sightedness
- The image focuses in front of the retina
2Pathology of myopia varies
- Japan -44 of adult pop.
- U.S. 20-25 of adults
- Reading and education level
- Are risk factors
- During one of the Chinese revolutions, they
killed people with glasses because it meant they
had read
3Hyperopia
- Farsightedness
- At times confused with loss of vision at onset of
age - Note ostrich eyes are bigger than its brain
4Ostriches are ridiculous
5Presbyopia
- Greek Presby old person
- Theory is that with age the crystallin lens loses
elasticity. - Become far sited
- So they get bifocals
- Ben Franklin
6Astigmatism
- defect of the eye, where vision is blurred by an
irregularly shaped cornea. - A refractive problem
- Might be able to focus in horizontal plane, but
not vertical
7Evolution of the Eye
- Homologous organ
- First eyes 540 mya
- arms race idea
8- Adaptation Birds have better vision
- Night birds can pick up U.V. Light
- Euglena bacteria has a light sensitive patch (2)
- Planarians have eyespots
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10- Is it too complex to evolve piece by piece?
- what good is half an eye?
- Argument from personal belief
- But there are a lot of sub optimal eyes in
nature. - Even in people a myopic person has an advantage
over the blind. - Humans dont have the best eyes by a long shot
- The mantis shrimp has eyes divided into three
parts trinocular vision. - We have 4 visual pigments, they have 16. Can
pick up U.V. and polarized light
11Sea Sickness
- In Part results from your brain focusing on
stable side of boat, waves moving closs, and
waves moving far away on the horizon.
12Decibels
- Logarithmic unit, measures sound levels
- Originally a bell was the amount of sound lost
over 1 mile of telephone line
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14Ear Wax
- Cerumen
- Cleans, lubricates (prevents itching), and
protects - From sebaceous and apocrine glands
- Two genetic types Wet Dominant, Dry recessive
- Asians, Am Indians Dry
- Africans, Europeans Wet
- Builds up in whales like rings in a tree
Wet type ear wax flouresces under U.V. light
15Taste Smell Chemical senses
16- McDonalds Fries
- Win best taste competitions
- Not the method, potatoes, or machinery
- Taste of fried foods determined by cooking oil
- McDs uses 7 cottonseed oil, 93 beef tallow a
fry has more beef fat/ oz than a burger - McDs world
- locations ?
17Obviously there was criticism
- McDs changed to pure veg. oil 1990
- Problem how to make them taste like beef without
using beef? - natural flavor
- Explains why most of our food taste the way it
does.
18Natural Flavor vs. Artificial Flavor
- Both are man made
- 90 of our food is for processed food
- Canning, freezing, dehydrating destroy flavor
- Big money in making flavor
- Name food brands
- Name the companies that makes flavor
19International Flavors Fragrances (IFF)
- Worlds largest flavor company
- Also makes smell of best selling perfumes,
deodorant, and soaps - 2005 1.9 Bil.
- Givaudan 2nd
- Haarman Reimer Largest German
- Takasago Largest Japanese
20Smell owns taste
- Aroma can be 90 of a foods flavor
- What evolutionary benefit would organisms with a
better sense of smell have? - Find food
- Distinguish good food from bad
Evolution puts pressure on us.
21Flavors vs. smells
- Taste buds can detect 5 basic flavors
- Sweet, sour, bitter, salty, astringent, umami
- About 4-10K taste buds on tongue, cheek, pharynx,
epiglottis - Bumps called papillae
- Olfactory system can percieve thousands of
different chemicals
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24Mastication releases gases
- Thin layer of nerve cells called olfactory
epithelium receives gases and transduces them
into smell signals - Brain combines smells signals with simple taste
signals and decides if its something you want to
eat.
25Food preferences personality form early in life
- Babies will adjust to hot spicy, bland health
food, or fast food depending on what the people
around them eat.
Baby eating sushi
26We dont know it all yet
- Psychosomatic effects happen
- Color of food can determine perception of its
taste - People can grow accustomed to bad smells.
- Come back from a long vacation and immediately
take a good whiff of what your house smells like.
Other people smell that whenever they visit you
27Aroma memory
- Nerve signals for smell go right past parts of
our brain associated with memory. - Smelling salts (ammonium carbonate can wake you
up by causing an inhalation reflex - Smells can bring back memories
- Comfort foods
- McDs makes billions on this (Happy Meals)
28Flavor in history
- Empires built, seas crossed, religions and
philosophies changed over taste. - Columbus went looking for flavor
- Salzburg Germany Founded to protect salt trade
- Saffron is 12 a gram
29- So artificial flavors cropped up from perfume
companies after canning started - German scientist playing with chemicals suddenly
lab smells like grapes ? methyl anthranilate ?
grape Kool-Aid? purplesaurus rex
301.4 Bil a year
- 10K new food products a year
- 9/10 fail
31Tech
- Spectrometers
- Gas chromatographs
- Vapor detectors
- Can discern chemicals at 1 ppb
- Human nose can tell 0.000000000003
- Dogs better still
32Complex flavors
- Coffee, roast beast, strawberries thousands of
chemicals at once - Chemical responsible for flavor of Bell pepper
only need 0.02 ppb a drop could flavor a
swimming pool - And its cheap flavor in 12oz of Coke ½ cent
33- Often though, 1 chemical provides the over-riding
sense of the food. - Ethyl-2-methyl butyrate apple
- Methyl-2-peridylketone popcorn
- Ethyl-3-hydroxybutanoate marshmallow
- Hexanal fresh cut grass
- 3-methyl butanoic acid B.O.
34So what?So natural flavor means its made using
old technology
- Natural
- Getting amyl acetate from distilling bananas with
a solvent
- Artificial
- Getting amyl acetate from mixing vinegar with
amyl alcohol, adding H2SO4 as a catalyst
Both taste exactly the same, both happen in the
same factory, but people want to see natural on
their label.
35Art or Science?
- Mouthfeel Its not just flavor,
- TA.XT2i Texture analyzer uses 250 probes to
create an artificial mouth that senses bounce,
creep, crunch, density, chewiness, gumminess,
lumpiness, rubberiness, slipperiness, softness,
wetness, spread, spring-back, tackiness - How do you juggle all of this with subtleties of
flavor?
36Genetics
- Dominant gene
- Phenylthiocarbamide, also known as PTC, or
phenylthiourea tastes very bitter or not at all
depending on genetics - Discovered when a guy at duPont accidently
spilled a bunch of crystalline PTC, some
complained, some did not - May explain why some people are more offended by
cig. smoke
37Super Taster
- 25 of people of European dissent
- Maybe more fungiform papillae
- Linked to food preference, body type
- Coffee, alcohol, may be too intense
- Olives too salty
38Things go horribly awry
- Ageusia (pronounced ay-GOO-see-uh) Loss of sense
of taste - From neural damage
- anosmia - a loss of the sense of smell.
- Cold
- Parkinsons
- Alzheimer's