Our information about the world around us is obtained through the stimulation of sensory
nerves in the peripheral nervous system, which relay this information to the brain.
brain is able to build a picture from these signals, and our perception of the world is
shaped by this input combined with experience.
Changes in the environment cause
sensory receptors that are specialized for a specific
(which sense) to trigger the
depolarization of sensory nerve endings and the firing of neurons for different types of
pressure, sound, touch, vibration, gravity
A. GENERAL PROPERTIES OF SENSORY NEURONS
1. Receptors as Transducers
All receptors act like transducers, in other words, they convert one type of energy into
another (like some of the equipment you use in your laboratory).
Each sensory organ
contains primary sensory receptor cells.
These cells have specialized endings that detect
small changes in a given stimuli that cause the cell to create electrical potentials that
usually generate an action potential.
After several synapses, the signals are eventually
passed to the cerebral cortex, which is when we may become conscious of the sensation,
or in other words, we
However, once sensation reaches this
level, the actual sensation has been processed by the CNS, and often modified by our
attention and previous experience.
Specialized sensory receptors exist for the various senses in each sense organ:
olfactory receptors in the epithelium of the nose
taste receptor cells on the tongue
touch and temperature nerve endings in the skin
hair cells in the organ of Corti in the inner ear
rods and cones in the retina of the eye
hair cells in the vestibular apparatus of the inner ear
Name some things you can sense that are not mentioned above.
2. Receptive Fields
Usually a sensory cell can detect only a small portion of the full range of possible stimuli
that your whole sensory system can detect.
This limited range of stimuli fall within that
cell’s receptive field.
Every sensory cell, no matter at what level of the nervous system,
has a receptive field, but for various reasons, the size of these receptive fields may vary by
a great deal.
What properties would be exhibited by a receptive field of the following primary sensory
Touch, Sight, Sound, Motion