What are holes in the surface of dendrites or certain cells muscles and glands that shaped to fit only neurotransmitters?

The holes in the surface of dendrites or certain cells, muscles, and glands that are shaped to fit only neurotransmitters are called receptors. Receptors are protein molecules that bind to specific neurotransmitters and initiate a cellular response. Each type of neurotransmitter has its own specific receptor, which ensures that the neurotransmitter only binds to the cells that are meant to respond to it.

When a neurotransmitter binds to a receptor, it causes a conformational change in the receptor that triggers a cascade of intracellular events. These events can lead to changes in gene expression, enzyme activity, or ion concentrations, which ultimately result in the cellular response that is characteristic of that particular neurotransmitter.

Receptors are essential for the proper functioning of the nervous system. They allow neurons to communicate with each other and with other cells in the body, and they play a critical role in regulating a wide variety of physiological processes, including mood, behavior, movement, and digestion.