46. Sensory Systems

The middle ear converts

a. Air pressure waves to fluid pressure waves

b. Air pressure waves to nerve impulses

c. Fluid pressure waves to nerve impulses

d. Pressure waves to hair cell movements

Which of the following sensory receptors is incorrectly paired with its category?

a. Hair cell . . . Mechanoreceptor

b. Taste receptor . . . Chemoreceptor

c. Rod . . . Electromagnetic receptor

d. Olfactory receptor . . . Electromagnetic receptor

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.

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

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

Considering that sounds and odors both trigger changes in the patterns of action potentials in sensory neurons, how does the brain perceive which sense is which when the action potentials reach the brain?

a. The action potentials stimulated by sounds are different in size and shape from those stimulated by odors.

b. The axons from different sensory neurons go to different areas of the brain.

c. Mechanoreception is not consciously perceived by the brain, whereas chemoreception is.

d. Chemoreception is not consciously perceived by the brain, whereas mechanoreception is.

Give three examples of how the sensory abilities of an animal correlate with its habitat or method of finding food and mates.

Eighty-year-old Mr. Johnson was becoming slightly deaf. To test his hearing, his doctor held a vibrating tuning fork tightly against the back of Mr. Johnson's skull. This sent vibrations through the bones of the skull, setting the fluid in the cochlea in motion. Mr. Johnson could hear the tuning fork this way, but not when it was held away from the skull a few inches from his ear. The problem was probably in the _________ . (Explain your answer.)

a. Auditory nerve leading to the brain

b. Hair cells in the cochlea

c. Bones of the middle ear

d. Fluid of the cochlea