314 Chapter 10
Test Your Knowledge
Match the vestibular organ on the left with its correct component
on the right.
- Utricle and saccule a. Cupula
- Semicircular canals b. Ciliary body
- Cochlea c. Basilar membrane
d. Otolithic membrane
- The dissociation of rhodopsin in the rods in response to light
causes
a. the Na^1 channels to become blocked.
b. the rods to secrete less neurotransmitter.
c. the bipolar cells to become either stimulated or
inhibited.
d. all of these. - Tonic receptors
a. are fast-adapting.
b. do not fire continuously to a sustained stimulus.
c. produce action potentials at a greater frequency as the
generator potential is increased.
d. are described by all of these. - Cutaneous receptive fields are smallest in
a. the fingertips. c. the thighs.
b. the back. d. the arms.- The process of lateral inhibition
a. increases the sensitivity of receptors.
b. promotes sensory adaptation.
c. increases sensory acuity.
d. prevents adjacent receptors from being stimulated. - The receptors for taste are
a. naked sensory nerve endings.
b. encapsulated sensory nerve endings.
c. specialized epithelial cells.- Which of these statements about the utricle and saccule are
true?
a. They are otolith organs.
b. They are located in the middle ear.
c. They provide a sense of linear acceleration.
d. Both a and c are true.
e. Both b and c are true. - Because fibers of the optic nerve that originate in the nasal
halves of each retina cross over at the optic chiasma, each
lateral geniculate receives input from
a. both the right and left sides of the visual field of both
eyes.
b. the ipsilateral visual field of both eyes.
c. the contralateral visual field of both eyes.
d. the ipsilateral field of one eye and the contralateral field
of the other eye.
Review Activities
- When a person with normal vision views an object from a
distance of at least 20 feet,
a. the ciliary muscles are relaxed.
b. the suspensory ligament is tight.
c. the lens is in its most flat, least convex shape.
d. all of these apply. - Glasses with concave lenses help correct
a. presbyopia. c. hyperopia.
b. myopia. d. astigmatism. - Parasympathetic nerves that stimulate constriction of the
iris (in the pupillary reflex) are activated by neurons in
a. the lateral geniculate.
b. the superior colliculus.
c. the inferior colliculus.
d. the striate cortex. - A bar of light in a specific part of the retina, with a
particular length and orientation, is the most effective
stimulus for
a. ganglion cells.
b. lateral geniculate cells.
c. simple cortical cells.
d. complex cortical cells. - The ability of the lens to increase its curvature and maintain
a focus at close distances is called
a. convergence. c. astigmatism.
b. accommodation. d. amblyopia. - Which of these sensory modalities is transmitted directly to the
cerebral cortex without being relayed through the thalamus?
a. Taste d. Hearing
b. Sight e. Touch
c. Smell - Stimulation of membrane protein receptors by binding to
specific molecules is not responsible for
a. the sense of smell.
b. sweet taste sensations.
c. sour taste sensations.
d. bitter taste sensations. - Epithelial cells release transmitter chemicals that excite
sensory neurons in all of these senses except
a. taste. c. equilibrium.
b. smell. d. hearing.
Test Your Understanding- Explain what is meant by lateral inhibition and give
examples of its effects in three sensory systems. - Describe the nature of the generator potential and explain its
relationship to stimulus intensity and to frequency of action
potential production.