How do chemical senses like taste and smell function?

Chemical senses like taste and smell function by detecting chemical molecules in our environment and transmitting this information to our brain.

Taste, also known as gustation, and smell, or olfaction, are two of the five traditional senses. They are classified as chemical senses because they detect chemical substances in our environment. These senses are crucial for survival, as they allow us to enjoy our food, detect danger (like smoke or spoiled food), and even influence our social interactions.

Taste involves the detection of chemicals dissolved in substances like food or drink. This process begins when you put something in your mouth and it dissolves in your saliva. The dissolved substances then come into contact with the taste buds on your tongue. Each taste bud contains a cluster of gustatory cells, which are the sensory cells responsible for taste. These cells have hair-like extensions called microvilli that protrude through a pore in the taste bud and come into contact with the dissolved substances. When the chemicals bind to receptors on the microvilli, they trigger electrical signals that are transmitted to the brain via sensory nerves, allowing us to perceive the taste.

Smell, on the other hand, involves the detection of volatile chemicals in the air. This process begins when you inhale and the airborne chemicals enter your nose. These chemicals then come into contact with the olfactory epithelium, a specialised tissue in the upper part of your nasal cavity that contains the sensory cells responsible for smell. These cells have hair-like extensions called cilia that are covered in mucus. When the chemicals dissolve in the mucus and bind to receptors on the cilia, they trigger electrical signals that are transmitted to the brain via the olfactory nerve, allowing us to perceive the smell.

Both taste and smell are closely linked and often work together to create our perception of flavour. For example, when you eat, the smell of the food can enhance the taste. This is why food can taste bland when you have a cold and your nose is blocked. In summary, our chemical senses play a vital role in how we interact with and perceive our environment.