Transcript Human Anatomy and Physiology I

Human Structure and
Function II
Special Senses
Olfactory sense –
The sense of smell
Both smell and taste use chemoreceptors.
Of all the senses, only smell and taste have
fibers that run to both cortical areas and
the limbic system.
Olfactory receptors are bipolar neurons.
Are replaced throughout lifetime, but lost at the
rate of about 1 % per year.
The cilia, or olfactory hairs are the sensitive portions
Chemical must be dissolved in watery mucus to
stimulate the receptor.
Combinations of primary scents allow us to recognize
thousands of different odors.
Gustatory sensations : Taste
Uses chemoreceptors
Substance must be dissolved before can be detected
Detects 4 basic sensations:
salty, sour, sweet and bitter
Also may have receptors for alkaline, metallic,
umami and water!