Taste Receptors

Each taste bud includes a group of modified epithelial cells, which are the taste cells (gustatory cells) that function as receptors. Each of our 10,000 taste buds houses 50 to 150 taste cells. The taste bud also includes epithelial supporting cells. The entire structure is somewhat spherical, with an opening, the taste pore, on its free surface. Tiny projections (microvilli), called taste hairs, protrude from the outer ends of the taste cells and jut out through the taste pore. These taste hairs are the sensitive parts of the receptor cells.

Interwoven among and wrapped around the taste cells is a network of nerve fibers. The ends of these fibers closely contact the receptor cell membranes. A stimulated receptor cell triggers an impulse on a nearby nerve fiber, which travels into the brain.

A chemical to be tasted must dissolve in the watery fluid surrounding the taste buds. The salivary glands supply this fluid. To demonstrate its importance, blot your tongue and try to taste some dry food; then repeat the test after moistening your tongue with saliva.

As is the case for smell, the mechanism of tasting probably involves combinations of chemicals binding specific receptors on taste hair surfaces, altering membrane polarization, and thereby generating sensory impulses on nearby nerve fibers. The amount of change is directly proportional to the concentration of the stimulating substance.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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