Warm-Up

If you had to live without one of your five senses, which one would you choose to lose and why?

SENSATION AND PERCEPTION

An Introduction

Sensation The stimulation of

sensory receptors and transmission of information to the central nervous system.

Perception Psychological process

through which we interpret sensory stimulation

Thresholds

Absolute Threshold The weakest amount of stimulus that can be

sensed. Difference Threshold

The minimum amount of difference that can be detected between two stimuli.

Absolute Threshold For HumansSense Stimulus Receptors Threshold

Vision Electromagntic Energy

Rods and cones in the retina

A candle flame viewed from a distance of about 30 miles on a dark night.

Hearing

Sound Waves

Hair cells of the inner ear

The ticking of a watch from about 20 feet away in a quiet room.

Smell Chemical substances in the air

Receptor cells in the nose

About one drop of perfume diffused throughout a small house.

Taste Chemical substances in saliva

Taste buds on the tongue

About 1 teaspoon of sugar dissolved in 2 gallons of water.

Touch Pressure on the skin

Nerve endings in the skin

The wing of a fly falling on a check from a distance of about .4 inch.

Detection and Adaptation Signal-Detection Theory

Your environment, physical state, mood, and your attitude can affect sensitivity to stimuli.

Sensory AdaptationProcess by

which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli.

VISION

Light is electromagnetic energy. We only see ROYGBIV, this is only a

fraction of all the possible colors in the electromagnetic spectrum. (infrared and ultraviolet light)

The Eye

Blank Diagram of the Eye

Parts of the Eye The Pupil

Lets in light. (think of a camera lens) Pupil size is sensitive to light and emotions. Allows dark and light adaptation for up to 45

minutes.

Parts of the Eye Lens

Adjusts to the distance of objects by changing its thickness.

When people squint, they are adjusting the thickness of the lenses in their eyes.

Parts of the Eye

Retina Sensitive surface – acts like the film of a

camera. Photoreceptors make it possible for the optic

nerve to carry the message to the brain.

Parts of the Eye

Cornea Protects the eye from germs, dust, etc. Contributes most of the eyes focusing power.

Parts of the Eye

Iris Colored portion of the eye.

Parts of the Eye

Optic Nerve Transmits visual information to the occipital

lobe of the brain.

Diagram of the Eye

Additional Eye Information

Blind Spot Spot where optic nerve leaves the eye

Rods and Cones Located in the Retina Rods are sensitive only to light, black and

white. Cones provide color vision.

Visual Acuity The sharpness of vision

Afterimages The color’s complementary color.

Colorblindness People who do not have normal color

vision. They are partially or totally unable to distinguish color due to an absence of, or malfunction in, the cones.

Total color blindness is rare. Partial color blindness is fairly common.

Red-Green color blindness is the most common.

Far more common among men because the deficiency is carried in the X chromosome.

Answer 25

Answer 29

Answer 56

Answer 6

Answer 8

Warm-Up

Colorblindness occurs in ______________ more often than in ______________.

What is the function of the Rods and Cones in the eye?

What happens if there is a problem with the Cones?

What are afterimages? What is the spot called where the optical

nerve leaves the eye?

HEARING

Hearing Sound travels through the air in waves. Changes in air pressure that result from

vibration causes sound waves. Anything that makes a sound causes a

vibration.

http://www.youtube.com/watch?v=s9GBf8y0lY0

Parts of Hearing Pitch

How high or low a sound is.

The Human ear can hear sound waves from 20 to 20,000 cycles per second.

Loudness Is determined by

amplitude – Sound Waves.

Loudness is measured by decibels (dB) 0 dB is the lowest we

can hear.

The Ear

Parts and Function

The shape of the ear is specifically made to capture sound.

3 sections of the ear Outer (what we typically think of as the ear) Middle (stretches from the eardrum through 3

small bones) Inner (consists of the cochlea and attaches to

the auditory nerve)

Parts and Function

Eardrum is the gateway for outer to middle ear.

As it vibrates it sends the vibration to 3 small bones in the middle ear. Hammer Anvil Stirrup

Parts and Function Those bones then send the vibration to

the inner ear. It reaches the cochlea, which looks like a

snail, but is a bony fluid filled tube that contains neurons and then connects to the auditory nerve.

Deafness About 2 million Americans are deaf. Deafness may be inherited, caused by

disease, injury or old age. Conducive deafness is caused by damage

to the middle ear. Usually in older people (can be helped with

hearing aids. Sensorineural deafness is caused by

damage to the inner ear. Usually caused by damage to the auditory

nerve through disease or prolonged exposure to very loud noises.

THE OTHER SENSESSmell, Taste, and Touch

The Nose

Smell

The receptor for the sensation of smell is the nose.

The olfactory nerve is the connection to the brain from the nose.

Taste and Smell are closely related.

The Tongue

Taste

There are four basic tastequalities.

Sweet Sour Salt Bitter

Taste is sensed through receptors on the tongue called taste buds.

Scraping or burning your tongue kills taste buds, they renew in about a weeks time.

Touch

Registering the Sensation of Touch

The are three ways we understand touch. Pressure Temperature Pain

Pressure is received by receptors around hair roots. Different parts of the body

are more sensitive than others.

Temperature is sensors that help you adapt to temperature changes. These are neurons just below the skin.

Touch Pain is adaptive because it

motivates us to do something to make it stop.

Pain goes from its point of contact – the spinal cord – to the thalamus – to the cerebral cortex, where prostaglandins, or chemicals that tell the brain of the pain, are released.

The Gate Theory suggests that only a certain amount of information can be processed so if you rub or scratch the area it helps pain go away. By doing so you flood the neurons.

Body Senses Vestibular Sense tells you

whether you are physically upright or upside down. Sensory organs located in the

ear monitor the body’s motion, balance, and tells you whether you are upside down or falling.

Kinesthesis is “to move” and “perception. It is when information is fed to the brain from sensory organs in the joints, tendons, and muscles.