Light coming in through the eye is focused on a layer of tissue at the back of the eye called the _______ by means of being bent, or refracted, by both the eye’s _______ and the ________ that lies behind it.

The eye’s photoreceptor cells come in two varieties:_______, which function in low- light situations but provide only _______ vision; and ______, which respond best to bright light but that provide.________ vision.

Visual information is passed from the eyes to the brain via our two_______.

Taste cells are part of organized collections of 50 to 100 cells known as _______. Taste works by means of “tastants” interacting with hair-like projections that extend from the_______.

Sound waves are collections of air molecules that are either more or less _______ than molecules of ambient air.

The inner ear’s cochlea is filled with _______; its vibrations open and shut “trapdoor” channels on _______ cells, thus resulting in the transmission of a nerve signal.

Each of our senses employs the cells known as _______, which can both respond to stimulation and transform their responses into _______.

All senses except _______ route their signals through the brain’s______, after which these signals go to differing parts of the _______ for additional processing.

The 340 to 380 types of olfactory receptors we have allow us to discriminate among a much greater number of smells because the various receptor types can send signals in different _______.

The spinal cord can receive input from _______and direct ________ in response, without input from the brain. This entire process is known as a_______.

The autonomic nervous system is divided into the sympathetic or “_______” division and the parasympathetic or “_______” division.