Structure:
The cerebrum's control center for smell is connected by the olfactory nerve,
to the enlargements at the distal end, called olfactory bulbs. Sensors
in the membranes of the mouth and nostrils are connected to the olfactory
bulbs. The olfactory nerve, Cranial
Nerve II, is actually an extension of the brain,
because it has no nerve cell body.
Function:
Based upon their structure, chemicals from the environment attach to some
of the many specific receptor structures in the mucus membranes of the
nose. Electrical signals generated there travel through the olfactory bulbs
and nerves, to the olfactory center; it identifys the smell, based on past
exposures to the chemical. A signal is also sent to the cerebrum where
memory associations are sorted, and appropriate responses, perhaps an escape
from a preditor, are generated by the motor cortex.
