PERCEPTION AND SENSESBiology 12

PERCEPTION AND INK BLOTS

Inkblots are just meaningless blobs of ink. Yet like clouds and rock formations, inkblots have stirred the Imagination for centuries. In recent years, serious attention has been given to the study of personality through inkblots.

How does an Inkblot test tell the psychologist something about personality? The inkblots don't really do anything. What's important is what people say about the image they see. You might say that the inkblots act as a mirror of the mind.

This kind of personality test is called a projective technique.

You've probably heard about the Rorschach Inkblot Test. Working with mental patients In Switzerland, Herman Rorschach In 1921, developed a system of analysis for inkblots which is still used today.

Perception is influenced by experience.

Since no two people ever have the same experience because of the interaction of learning, environment and genetics... No two people can ever perceive the world in exactly the same way!

WHAT DO YOU SEE?

WHAT DO YOU SEE?

WHAT DO YOU SEE?

WHAT DO YOU SEE?

WHAT DO YOU SEE?

OPTICAL ILLUSIONS

TED Talk – how to fool your brain (16 mins):

http://www.ted.com/talks/lang/eng/beau_lotto_optical_illusions_show_how_we_see.html Check these out! http://www.optillusions.com/

SENSE RECEPTORS Separate receptors located in the skin detect different types of touch stimuli:1. Touch receptors called Meissner’s Corpuscle

2. Pressure receptors called Pacinian Corpuscle

3. Pain receptors that are free nerve endings

4. Heat receptors called Ruffini’s end organ

5. Cold receptors called Krause’s end bulbs

VISION

SCLERA

The white part of the eyeball is called the sclera

The sclera is made of a tough material and has the important job of covering most of the eyeball.

Look very closely at the white of the eye, and you'll see lines that look like tiny pink threads. These are blood vessels.

CORNEA

The part of the sclera in front of the colored part of the eye is called the cornea.

Unlike the rest of the sclera, which is white, the cornea is transparent, or completely clear, which lets light travel through it.

The cornea helps the eye focus.

Cataract

IRIS Behind the cornea are the iris and the pupil.

The iris is the colorful part of the eye.

When we say a person has blue eyes, we really mean the person has blue irises!

PUPIL The iris is a muscle. This allows the iris to control how much light goes through the pupil.

The pupil is the black circle in the center of the iris, and it lets light enter the eye. The pupils will get smaller when a light shines near them and they'll open wider when the light is gone.

LENS

Held behind the pupil by ciliary muscles

The ciliary muscles can change the shape of the lens which allows the eye to focus on objects at different distances.

AQUEOUS HUMOR

The space between the cornea and the lens is filled with a liquid called aqueous humor.

This gives the eye oxygen, protein, and glucose.

VITREOUS HUMOR

The thick liquid inside the eyeball is called vitreous humor.

This gives the eye its shape.

RETINA Your retina is in the very back of the eye, past the vitreous humor.

It is smaller than a dime, it holds millions of cells that are sensitive to light.

The retina takes the light the eye receives and changes it into nerve signals so the brain can understand what the eye is seeing.

The retina is made up of ganglia, nerve fibers and photoreceptors which are like the film in a camera.

The focal point of the retina is called the fovea

There are two types of photoreceptors:Rods and Cones

RODS

Rods are stimulated in lower light They are found outside the area of the fovea

They allow us to see in black and white

CONES

Cones are sensitive to brighter light

They are responsible for colour vision and are concentrated in the fovea.

The retina has three types of cones - red, green, and blue - to help you see different ranges of color.

Together, these cones can sense combinations of light waves that enable our eyes to see millions of colors.

OPTIC NERVE

Axons from the rods and cones gather to form a bundle of nerves called the optic nerve

The location where the optic nerve leaves the eye is called the blind spot.

Find your own blind spot!

EYE ANIMATION

http://www.wisc-online.com/Objects/ViewObject.aspx?ID=AP14304

http://www.kscience.co.uk/animations/eye.swf

HEARING

The ear picks up compressions of air that we call sound waves.

MOVING AIR MOLECULES ARE CHANGED TO NERVE SIGNALS BY THE EAR

Sound waves in air (gas) vibrations in bone (solid) waves in a fluid in the inner ear (liquid) electrical nerve signals

EXTERNAL EAR Pinna - outer ear - takes sound from large area and funnels it into a small space

Auditory canal – carries sound waves to eardrum

MIDDLE EAR

Eardrum (tympanic membrane)

Ossicles – three small bones (malleus, incus, stapes) that vibrate and amplify sound

The stapes strikes the covering of the oval window on the cochlea

Eustachian tube - connects the middle ear to the throat and helps maintain air pressure

EAR ‘POPPING’

Air is less dense so there is less pressure on the tympanic membrane.

You can reduce air pressure in Eustachian tube by swallowing, yawning or chewing gum!

WHAT IS AN EAR INFECTION?

Build up of fluid in Eustacian tube which leads to unequal air pressure!

INNER EAR

Vestibule - communicating chambers and tubes involved in equilibrium

Semicircular Canals – fluid filled structures involved in equilibrium

Cochlea – coiled tube that receives sound waves and converts them to nerve impulses (sense of hearing)

Organ of Corti - contains hearing receptors, hair cells detect vibrations

Auditory nerve is the main nerve leading from ear to brain

Sensory information is interpreted by the temporal lobe of the cerebrum

THE HEARING PROCESS

1. Sound waves enter external ear2. Eardrum vibrates3. Auditory ossicles (malleus, incus, stapes) amplify vibrations4. Stapes hits oval window and transmits vibrations to cochlea5. Organs of corti contain receptor cells (hair cells) that deform from vibrations6. Impulses sent to the auditory nerve7. Auditory cortex of the temporal lobe interprets sensory impulses

Anatomy of the ear: http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP1502

http://bcs.whfreeman.com/thelifewire/content/chp45/4502001.html

How Sound Affects us!

http://www.ted.com/talks/lang/eng/julian_treasure_the_4_ways_sound_affects_us.html

SENSES STATIONS ACTIVITY!

There are 10 stationsThe class will be divided into groups of 2 or 3

As a group, you will cycle through each station

Record your observations as you go

You will have 2-3 minutes per station

TASTY BUDS

Taste buds detect four different characteristics of food.

Each of these types of receptors bind to a specific structure of a ‘taste’ molecule.

Sweet receptors recognize hydroxyl groups (OH) in sugars.

Sour receptors respond to acids (H+). Salt receptors recognize the metal ions (eg Na+).

Alkaloids trigger the bitter receptors (Alkaloids are nitrogen containing bases with complex ring structures).

Many poisons are alkaloids and the presence of the receptors for bitter taste at the back of the tongue may help trigger the vomiting response

UMAMI

The 5th taste – described as ‘savouriness’. It is the taste of some amino acids and RNA molecules

It is described as a ‘brothy’, mouth-coating feeling

Found in meats and ‘hearty’ vegetables. All taste buds can detect umami.http://www.youtube.com/watch?v=71O1CPEWNVY

SMELL

Did you know that 80-90% of what we perceive as ‘taste’ is actually due to smell.

The olfactory bulbs are also directly linked to the amygdala (emotion centre of the brain) – this accounts for smell evoking such strong emotional attachment and memories!

SOMETHING COOL!

Synaesthesia – crosswired senses! http://www.youtube.com/watch?v=KApieSGlyBk

http://www.youtube.com/watch?v=1R_A4tUMOtI&feature=related

Super-Computer Brains!

http://www.ted.com/talks/lang/eng/henry_markram_supercomputing_the_brain_s_secrets.html

http://www.youtube.com/watch?v=KaC6SZsbmsg

Pushing the limits of the human body – Episode 3 Sensation (43mins)