Download The Senses - Ms. Fahey

The Senses
The five senses are …
• Vision, Hearing, Taste, Touch and Smell
• All these senses are received as AP’s from
sense organs. The brain interprets these
messages to provide our sensory inputs as we
know them.
The Eye
• The best way to understand function of the
eye is to compare it to a camera. A camera
creates images by focusing on an object and
allowing specific amounts of light to pass
through a hole to create a visual impression
on film. The eye functions in much the same
way.
Focus
• When light enters the eye, it passes through
the cornea (camera lens) where 2/3 of focus is
achieved. The light then passes through the
pupil where the iris (aperture) adjusts the
amount of light that is allowed to enter. The
remaining 1/3 of focus is then achieved when
the light passes through the lens (camera
lens).
Focus
• Accommodation is one of the focusing mechanisms
of the eye.
• The shape of the lens can adjust (either thinner or
thicker) by tensing or relaxing the muscles of the eye.
The focused light finally reaches the retina (film)
where it is converted by the rods and cones into a
signal that can travel to the brain (film development).
Once the image reaches the brain, you have sight.
Problems
• Changes in the shape and size of your eyes can
cause problems that affect the way you see
things that are close up or far away. These
problems are referred to as refractive
disorders. Refractive disorders include myopia
(nearsightedness), hyperopia (farsightedness),
and astigmatism.
The Ear
• The Ear has two main functions – balance and
hearing.
• There is an inner, outer and middle section of
the ear.
Parts of the Ear
• Outer Ear: Comprising the pinna, ear canal,
and outer layer of the eardrum.\
• Middle Ear:
• Inner Ear:
Parts of the Ear
• Inner Ear: The last energy transformation
occurs here. Mechanical energy is
transformed into the traveling wave pattern of
the basilar membrane.
Skin Receptors
•
•
•
•
•
•
Heat
Pressure
Touch
Cold
Pain
All send messages to the brain via sensory
neurons
Taste Receptors
• There are four types of
receptors on the tongue
• Salty
• Sour
• Bitter
• Sweet
Smell Receptors
• Smell is a chemical sense (as is taste)
• Chemicals enter the nasal passages and are
picked up by a mucus layer. Receptors in the
mucus pass messages to the brain using the
olfactory nerves.
• Receptors for smell are much more sensitive
than taste receptors.
Taste Receptors