Which sensory distinction is not encoded by a difference in neuron identity?
a. White and red
b. Red and green
c. Loud and faint
d. Salty and sweet

Evaluate the following statements according to the information presented in this chapter. Select True or False for each statement.

T/F Most human eyes have one type of rod and three types of cones.

T/F Rods are more sensitive to dim light than cones are.

T/F Nocturnal animals have fewer rods than diurnal animals.

T/F Both rods and cones use retinal and opsins to detect light.

Which of the following are not known to be present in human skin?

a. Thermoreceptors

b. Electromagnetic receptors

c. Pressure receptors

d. Pain receptors

Which of these statements about taste is true?

a. Sweetness is a measure of the concentration of hydrogen ions in food.

b. Sodium ions from foods can directly depolarize certain taste cells.

c. All bitter-tasting compounds have a similar chemical structure.

d. Sourness is detected when hydrogen ions bind to membrane receptors.

The human brain differentiates tastes from smells because action potentials for the two sensations differ in

a. Magnitude and shape.

b. Threshold potential.

c. Where they are received in the brain.

d. How long they take to reach the brain.

What do the receptor cells in the lateral line system along the sides of a shark and the cochlea of your ear have in common?

a. They use hair cells to sense sound or pressure waves.

b. They are organs of equilibrium.

c. They use electromagnetic receptors to sense pressure waves in fluid.

d. They use granules that signal a change in position and stimulate their receptor cells.

What type of sensory system do migrating birds use to detect direction?

The transduction of sound waves into action potentials occurs

a. In the tectorial membrane as it is stimulated by hair cells

b. When hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons

c. As the basilar membrane vibrates at different frequencies in response to the varying volume of sounds

d. Within the middle ear as the vibrations are amplified by the malleus, incus, and stapes

If you look away from this book and focus your eyes on a distant object, the eye muscles _________ and the lenses _________ to focus images on the retinas.

a. Relax . . . Flatten

b. Relax . . . Become more rounded

c. Contract . . . Flatten

d. Contract . . . Become more rounded