
If you had to live without one of your five
senses, which one would you choose to lose
and why?
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

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.
Sense
Stimulus
Receptors
Vision
Electromagnt Rods and
ic Energy
cones in the
retina
Threshold
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.

Signal-Detection Theory

Your environment, physical state, mood, and your
attitude can affect sensitivity to stimuli.
Sensory
Adaptation
Process by
which we
become
more
sensitive to
weak stimuli
and less
sensitive to
unchanging
stimuli.


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 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.

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.

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.

Cornea


Protects the eye from germs, dust, etc.
Contributes most of the eyes focusing power.

Iris

Colored portion of the eye.

Optic Nerve

Transmits visual information to the occipital lobe of
the brain.

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





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?

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



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 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)



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


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.



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.
Smell, Taste, and Touch



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.

There are four basic taste
qualities.






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.

The are three ways we
understand touch.




Pressure is received by
receptors around hair roots.


Pressure
Temperature
Pain
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.


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.

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.