Sensitive cells:
In our body there are several cells which are specialized in collecting information from the outside. These "receivers" can be found in the senses:

Taste: We have taste buds (also known as gustatory cells) in our tongue. They are responsible for detecting the flavors of substances dissolved in water.

Smell: we have a membrane called olfactory bulb in our nose. It is formed by multiple olfactory cells that are responsible for perceiving odours.

Skin: There are different receptors, called tactile corpuscles, which are specialized in detecting different sensations. For instance: cold, heat, pressure or touch. Free nerve endings are responsible for the sensation of pain.

Sight: We have cells sensitive to light, cones sensitive to bright light, and rods sensitive to dim light.

Hearing: the earliest receiver of sound is the eardrum, a small membrane that vibrates when it receives acoustic waves and transmits this vibration to a chain of auditory ossicles called Hammer (also called Malleus), Anvil (also known as Incus) and Stirrup (also called Stapes) that carry sound to the inner ear, where we also have the semi-circular ducts (or semi-circular canals), which are three very small tubes which are filled with a liquid substance and where there are some tiny receptors associated to equilibrium.