c. The general senses in humans include pain, temperature (warm and cold),
touch (light and deep), and proprioception ("body sense": posture, tone, tension).
d. The special senses in humans include smell (olfaction), taste (gustation),
e. The input from each special sensory receptor goes to its own specific area of
the opposite cerebral hemisphere. The general sensory pathway is from the receptor
organ, via the PNS nerves, to the CNS. This general pathway then ascends fiber tracts
in the neuraxis. The pathway ends in the central area of the cerebral hemisphere (on
the side opposite to the input).
Section VII. THE SPECIAL SENSE OF SMELL (OLFACTION)
11-22. SENSORY RECEPTORS
Molecules of various materials are dispersed (spread) throughout the air we
breathe. A special olfactory epithelium is located in the upper recesses of the nasal
chambers in the head. Special hair cells in the olfactory epithelium are called chemore-
ceptors, because they receive these molecules in the air.
11-23. OLFACTORY SENSORY PATHWAY
The information received by the olfactory hair cells is transmitted by way of the
olfactory nerves (cranial nerves I). It passes through these nerves to the olfactory bulbs
and then into the opposite cerebral hemisphere. Here, the information becomes the
sensation of smell.
Section VIII. THE SPECIAL SENSE OF TASTE (GUSTATION)
11-24. SENSORY RECEPTORS
Molecules of various materials are also dispersed or dissolved in the fluids
(saliva) of the mouth. These molecules are from the food ingested (taken in). Organs
known as taste buds are scattered over the tongue and the rear of the mouth. Special
hair cells in the taste buds are chemoreceptors to react to these molecules.
11-25. SENSORY PATHWAY
The information received by the hair cells of the taste buds is transmitted to the
opposite side of the brain by way of three cranial nerves (VII, IX, and X). This
information is interpreted by the cerebral hemispheres as the sensation of taste.