How are these cells well adapted to their functions?

Olfactory receptor cells are bipolar neurons with dendrites facing the interior space of the nasal cavity and an axon that passes through the cribiform plate then travels along the olfactory nerve to the olfactory bulb. It's function is to collect odorant molecules via receptors and generate an action potential that transmits the signal to the brain. Without the receptor that is exposed at the interior space of nasal cavity, it wouldn't be able to collect odorant molecules.

Rods cannot distinguish colors, but are responsible for low-light black-and-white vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity. Because of the rhodospin pigment, they are able to distinguish images and transmit the image to the brain. Cones are mostly concentrated in and near the fovea and see colour. Objects are seen most sharply in focus when their images fall on the fovea. Both the cone cells and rods are connected through intermediate cells in the retina to nerve fibers of the optic nerve where signals are transmitted.