The sense organs — eyes, ears, tongue, skin, and nose — help to protect the body. The human sense organs contain receptors that relay information through sensory neurons to the appropriate places within the nervous system. Each sense organ contains different receptors.
•General receptors are found throughout the body because they are present in skin, visceral organs (visceral meaning in the abdominal cavity), muscles, and joints. •Special receptors include chemoreceptors (chemical receptors) found in the mouth and nose, photoreceptors (light receptors) found in the eyes, and mechanoreceptors found in the ears. Oooh, that smell: Olfaction
Olfactory cells line the top of your nasal cavity. On one end, olfactory cells have cilia — hair-like attachments — that project into the nasal cavity. On the other end of the cell, are olfactory nerve fibers, which pass through the ethmoid bone and into the olfactory bulb. The olfactory bulb is directly attached to the cerebral cortex of your brain. As you breathe, anything that is in the air that you take in enters your nasal cavity: hydrogen, oxygen, nitrogen, dust, pollen, chemicals. You don’t “smell” air or dust or pollen, but you can smell chemicals. The olfactory cells are chemoreceptors, which means the olfactory cells have protein receptors that can detect subtle differences in chemicals. The chemicals bind to the cilia, which generate a nerve impulse that is carried through the olfactory cell, into the olfactory nerve fiber, up to the olfactory bulb and to your brain. Your brain determines what you are smelling. If you are sniffing something that you haven’t experienced before, you need to use another sense, such as taste or sight, to make an imprint in your brain’s memory. Mmm, mmm, good: Taste
The senses of smell and taste work closely together. If you cannot smell something, you cannot taste it, either. Taste buds on your tongue contain chemoreceptors that work in a similar...