Sense of Taste or Gustation?-Mechanism Of Action Of Taste Bud

Gustation is the ability to taste or smell food before eating it. In humans, gustation is mainly controlled by the olfactory system, which consists of two parts: the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB). Taste is the sense that allows us to perceive sweet, sour, salty, bitter, hot, or cold.

The receptors for taste are chemoreceptors. They may be on the body surface of an animal. Or they may be present in the mouth and throat.

Taste Bud In Mammals

The surface of the mammalian tongue is covered with many small protuberances. These protuberances are called papillae. Papillae give the tongue its “bumpy” appearance. Thousands of taste buds are present in the crevices between the papillae. Taste buds have two types of cells.

(A) Gustatory Cells:

They are barrel-shaped clusters of chemoreceptor cells.

(B) Supporting Cells:

They give support to gustatory cells. Both these cells are arranged like alternating segments of an orange. Gustatory hairs extend from each receptor cell. These hairs project through a tiny opening called the taste pore. Sensory neurons are associated with the basal ends of the gustatory cells.

Mechanism Of Action Of Taste Bud

The four common tastes are sweet (sugars), sour (acids), bitter (alkaloids), and salty (electrolytes). The exact mechanism of stimulation of a chemoreceptor taste cell is not known. One theory is that different types of proteins are present on the surface of the receptor-cell plasma membrane. Different gustatory stimuli change the proteins. It changes the permeability of the membrane. It opens the gates of chemical stimuli. It causes a generator potential.

2. Taste Buds In Reptiles And Birds

Other vertebrates also have taste buds. But they are present in the other parts of the body. For example, reptiles and birds do not have taste buds on their tongue. Most taste buds are present in the pharynx.

3. Taste In Fishes And Amphibians

The taste buds are present in the skin of fishes and amphibians.

(a) Taste buds in sturgeon are abundant on its head projection. It is called the rostrum. The sturgeon glides over the bottom and its foretaste of food.

(b) In other fishes, taste buds are widely distributed in the roof, side walls, and floor of the pharynx. They monitor the incoming flow of water.

(c) Some fishes like catfish, carp, and suckers feed in the bottom. The taste buds are distributed over the entire surface of their head, body, and the tip of the tail. They are also abundant on the barbells of catfish.

Read about Skin of Fishes