Sensory System

Although we often assume that our sense organs are reporting a complete picture of the world to our brains, in fact the world is full of stimuli (very low frequency sound, cosmic rays, electrical fields, etc.) that our sense organs cannot detect. This situation is best characterized as a failure of our sense organs to do what to these stimuli?

You look all over for your glasses and then find them pushed back onto your forehead. This error could be attributed to __________.

A fish detects vibrations in the water around it by means of its lateral lines, rows of sensory receptors along each side of the body. Based on what you know about sensory receptors, the lateral line receptors are probably which of the following?

If we wait too long between meals, our blood glucose levels drop. Which receptors will respond to this decrease in blood glucose?

Which of the following classes of sensory receptors consists of neurons with naked dendrites?

The round window is found __________.

Organs in the inner ear of mammals are the cochlea, semicircular canals, and vestibule. Match them to their functions.

Sitting too close to the amplifiers at a concert may __________.

The brain determines the loudness of a sound from the __________.

If the basilar membranes in the ears were equal in width and flexibility along their length, how would this affect a person's sense of hearing?

A person born without otoliths in the ears would be __________.

Compound eyes are advantageous for small prey species to detect a potential predator because __________.

In the vertebrate eye, the __________ focuses light on the photoreceptors.

Which of the following correctly traces the path of light into your eyes?

What is the fluid in the anterior chamber of the eye?

Difficulty in distinguishing red from green is most likely due to a defect in which cells?

A human born with nonfunctional rhodopsin would __________.

Which of the following occurs when you move from a bright area into a darkened room?

Which of the following choices is the correct order of the neural pathways that light travels after hitting the retina?

Correct focusing of the image on the retina in humans is achieved by changing the __________.

The body uses the vitamin A precursors from some foods to make a substance called retinal, which __________.

When you move an object from 15 inches in front of your eyes to 10 inches in front of your eyes, the lenses __________.

The greatest concentration of cone receptors is found at the __________.

Some sensory processing occurs within the retina of the vertebrate eye. In one type of retinal processing, a horizontal cell that receives input from a stimulated rod or cone then inhibits surrounding photoreceptors and bipolar cells. This type of processing is called __________.

Incapacitating the muscles of a mammalian eye would result in an inability __________.

A baby is born with the normal number and distribution of rods but no cones. What would we expect the baby to be?

Which of the following statements is correct?

Taste and smell are two distinct senses in animals living in terrestrial environments. Animals living in aquatic environments, however, have no distinction between taste and smell. Which response might explain this difference?

Which sensory receptor—category pair is correct? (A)hair cell—nociceptor (B)snake pit organ—mechanoreceptor (C)taste receptor—chemoreceptor (D)olfactory receptor—electromagnetic receptor

Which of the following sensory receptors is incorrectly paired with its category? a. hair cell—mechanoreceptor b. snake pit organ—thermoreceptor c. taste receptor—chemoreceptor d. olfactory receptor—electromagnetic receptor

Complete this concept map summarizing sensory receptors.

In the human ear, how do different hair cells respond to different frequencies of sound? a. Waves of pressure move through the fluid in the cochlea. b. Hair cells are “sandwiched” between membranes. c. Receptor proteins in the stereocilia of each hair cell are different; each protein responds to a certain range of frequencies. d. Because the basilar membrane varies in stiffness, it vibrates in certain places in response to certain frequencies.

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 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.

How does your brain determine the volume and pitch of sounds?

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

Compare and contrast the lateral line system of fishes with electroreception in sharks.

When you first sit down to read in a coffee shop, the surroundings seem very loud. Yet after a few minutes reading you realize you hardly notice the noise at all. Why is that?

Scientists generally think that a “good hypothesis” is one that is reasonable and testable and inspires further research into a phenomenon. Using these criteria, explain whether Dalton’s hypothesis about color vision was a good hypothesis. Was it correct?

Hold your right eye closed. With your left eye, look at the + in the image below. Starting from about two feet away, slowly bring your head closer while looking at the +. What happens to the dot when you get close to the image? What property of the eye’s structure does this exercise demonstrate?

Scientists collected data on the date of onset of the menstrual cycles in a group of women who moved into a college dormitory together in the fall. The y-axis of the graph shows the mean difference (in days) between the onset of a woman’s cycle and the average onset date of the rest of the women. Evaluate whether these data provide evidence for the existence of a human pheromone.

Construct a graph in which membrane potential is on the y axis and time is on the x axis. Then draw the action potentials that occur when a bitter flavor is absent, followed by the action potentials that result when a person tastes a bitter flavor.

Design experiments to test the hypothesis that electric eels are both electrogenic and electroreceptive.

SCIENTIFIC THINKING We know that sea turtle hatchlings use Earth’s magnetic field to navigate. Do they also use light cues from the moon to get from the sand to the ocean waves? Outline an experiment to answer this question.

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? Scientists have identified dozens of pheromones used by honeybees for communication. Which type of sensory system uses pheromones? a. mechanoreception b. photoreception c. chemoreception d. thermoreception e. electroreception

Have you ever felt your ears ringing after listening to loud music? Can this permanently impair your hearing? Should manufacturers of music devices and producers of concerts be required to warn consumers? What effect might warnings have?

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? Honeybees produce an alarm pheromone when their hive is molested. This pheromone stimulates the bees to protect the hive. If you were to count the number of alarm pheromone receptors in honeybee tissues, which type of bee would likely have the most—a queen, a drone, or a worker? Why?

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? Why might an alarm pheromone be more effective for triggering a protective response in a hive than signals that involve other senses, such as vision or hearing?

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? Researchers observed that the queen produces a pheromone that attracts both drones and workers. They hypothesized that this pheromone inhibits ovarian development in the workers, making the workers infertile. To test this hypothesis, they exposed workers to a synthetic version of the queen pheromone and then recorded their “ovary development score.” (Higher scores indicate more fully developed ovaries.) The results are shown in the graph here. Do these results support the researchers’ hypothesis? Why or why not? (*** signifies P<0.001.)

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? In the experiment described in Question 14, the researchers dissolved the queen pheromone in diethyl ether, a chemical that helps volatilize the pheromone, making it easier for the workers to detect it in the air. The control treatment consisted of plain diethyl ether. Why did they use this as the control, instead of simply not exposing the workers to any chemical?

Honeybees live in social groups consisting of a queen, up to several hundred male drones, and thousands of infertile female workers. The drones mate with the queen only, and the workers protect the hive, forage, and feed and groom the queen. The health of the hive depends on the female workers performing these duties instead of reproducing. What roles do pheromones play in maintaining a functional beehive? Beekeepers carefully manage their beehives by adding mated queens, drones, and workers at appropriate times. However, sometimes the bees abandon a new hive before the queen can mature, and the result is inefficient hive management and honey production. Suggest a potential use of queen pheromone in controlling this problem.