Sensory what we perceive after a stimulus. For

Sensory Modalities

                       A sensory modality is a way of
sensing, like vision or hearing. Modality in
someone’s voice gives a sense of the person’s mood. In logic, modality has to do with whether a
proposition is necessary, possible, or impossible. In general, Amodality is a particular way in
which something exists.

Stimulus modality, also called sensory modality, is one aspect of a
stimulus or what we perceive after a stimulus. For example, the
temperature modality is
registered after heat or cold stimulate a receptor. Some sensory modalities include:
light, sound, temperature, taste, pressure, and smell.

General Senses:

1.  Somatic (Exteroceptors)

a.  Touch b. 
Pressure c. Temperature d. Proprioception e.  Pain

2.  Visceral (Interoceptors)

                                    a.  Pain       b.

Special Senses

a.  Smell or
Olfaction b.  Taste or Gustation c.  Sight or Vision

          d.  Sound or Auditory   e. 
Balance or Equilibrium

Stimulation of a sensory
Transduction of the stimulus

                   Conversion of the stimulus
into a graded potential

Generation of an impulse

                   Conversion of a graded
potential into an action potential at a trigger zone and propagation to CNS.

of sensory input


                   Auditory learners learn best
through hearing, using their ears and their voices as the primary way to learn.
They learn best through verbal lectures, discussions, talking things through
and listening to what others have to say. Auditory learners interpret the
underlying meanings of speech through listening to tone of voice and other
nuances. Written information may have little meaning until it is heard. These
learners often benefit from reading text aloud and using a tape recorder.


              Visual learners need to see the
material to learn most effectively. They need to see the teacher’s body
language and facial expression to fully understand the content of a lesson.
They may think in pictures and learn best from visual displays including
diagrams and hand-outs. During a lecture or classroom discussion, visual
learners often prefer to take detailed notes to absorb the information.


                      Kinesthetic learners are those who learn
best by doing. Kinesthetic persons learn best through a hands-on approach and
actively exploring the physical world around them. They may find it hard to sit
still for long periods and may become distracted by their need for activity and


                                  A sensory
nerve cell or sense organ, as of smell, or taste, that are able to detect and
respond to chemical stimuli.              

A sensory receptor that detects chemical stimuli in the
environment and relay that information to the central nervous



                   A chemoreceptor, also known as chemosensor, is a specialized sensory
receptor cell which transduces (responds to) a chemical substance
(endogenous or induced) and generates a biological signal. This signal may be
in the form of an action potential if the chemoreceptor is a neuron (nerve
cells or in form of neurotransmitter that activate nearby a nerve fibers if
chemosensor is a specialized sensory receptor cell, such as taste receptor in taste bud or in
internal peripheral
chemoreceptor such as carotid body. In more general
terms, a chemosensor detects toxic or hazardous chemicals in the internal or
external environment of the human body and transmits that information to
the central
nervous system, and rarely
the peripheral
nervous system, in order to
expel the biologically active toxins from the blood, and prevent further
consumption of alcohol and/or other acutely toxic recreational intoxicants.


Examples of distance chemoreceptors

Example 1

                 Olfactory receptor neurons in
the olfactory system.Olfaction involves the ability to detect chemicals in the
gaseous state. In vertebrates, the olfactory system detects odors and
pheromones in the nasal cavity.Within the olfactory system there are two
anatomically distinct organs: the main olfactory epithelium (MOE) and the vomeronasal organ. It was initially thought that
the MOE is responsible for the detection of odorants, while the VNO detects pheromones. The current view, however, is
that both systems can detect odorants and pheromones. Olfaction in
invertebrates differs from olfaction in vertebrates. For example, in insects,
olfactory sensilla are present on their antennae.

Example 2

Those buds which are used in taste are present in the gustatory system.The
primary use of gustation as a type of chemoreception is for the detection of
taste ants. Aqueous chemical compounds come into contact with chemoreceptors in
the mouth, such as taste buds on the tongue, and trigger responses. These
chemical compounds can either trigger an appetitive response for nutrients, or
a defensive response against toxins depending on which receptors fire. Fish and
crustaceans, who are constantly in an aqueous environment, use their gustatory
system to identify certain chemicals in the mixture for the purpose of
localization and ingestion of food.

Example 3

Insects use contact chemoreception to recognize
certain chemicals such as cuticular hydrocarbons and chemicals specific to host
plants. Contact chemoreception is more commonly seen in insects but is also
involved in the mating behavior of some vertebrates. The contact chemoreceptor
is specific to one type of chemical.