Receptor cells that are neurons with sensory dendrites are faster than receptor cells that are separate from neurons. Why is that, and why might that be important in, for example, the sense of touch versus vision?

What are the receptor cells in the eye that are most sensitive to light and that give an image in black / white (grayscale)?

Imagine you wake up to the smell of smoke, The sound of the fire alarm, the flashing lights of sirens, the acreage taste of smoke in the air. In other words, all your senses are reacting to this emergency. Your body goes into "flight or fight mode".  Question: in about two paragraphs, can you describe the sensory pathway that the sensory information from just one of these special senses takes to the brain to be integrated. for example, if you were describing the smell of the smoke, how was odor detected? Which cranial nerves are involved? Where are those located? Where do they connect to the rest of the brain?

An example of a sensory neuron is one that leads from a pain receptor in the finger to the spinal cord. A pin can be pressed against the skin without eliciting a response from the pain receptor. However, if the pin is jabbed into the finger, the pain receptor may be stimulated and the finger would quickly be withdrawn through a reflex arc. How do we sense different types of pain (very painful vs. not painful at all)? Using the threshold potential and the all-or-none principle, explain how it is possible to sense different levels of pain.