PCB chapter 6
Which of the following statements about taste is true?
H+conveys sour, sugars convey sweet, amino acids convey umami
What defines a cell as an afferent neuron?
It has an axon that carries information to integrating centers.
__________ are a kind of receptor that respond to extremely strong stimuli, including those that may cause tissue damage.
Nociceptors
Which of the following choices is FALSE regarding rhabdomeric photoreception?
The absorption of light leads to cell hyperpolarization.
For sensory receptor cells, the "threshold of detection" is the weakest stimulus that produces
a response 50 percent of the time
What is true about the chromophore?
absorbs energy from photons, covalently linked to a member of opsin gene family, and plays a role in photoreceptor sensitivity to different colors, derivative of vit A
__________ send signals in the form of action potentials from periphery to integrating centers such as brain
afferent neurons
In the mammalian inner ear, inner hair cells detect sounds, while outer hair cells __________.
amplify sounds
In arthropods, the primary olfactory organs are generally located on the
antennae
Touch and pressure receptors can be broadly grouped into three categories: tactile receptors, proprioceptors, and __________.
baroreceptors
A thin piece of dome-shaped cuticle was found near one of the joints in a cricket leg. When it was removed, the animal could no longer make coordinated movements, but it could still respond to the rapid approach of a predator. This structure is most likely a
campaniform sensilla
The compound called __________ can stimulate warm-sensitive neurons.
capsaicin
Which of the following structures from the vertebrate inner ear is NOT part of the vestibular apparatus?
cochlea
Ruffini corpuscles are associated with __________ and detect __________.
connective tissue of skin; skin stretch
A tympanal organ functions as an insect __________
ear
In vertebrates, olfactory receptor cells are bipolar sensory neurons, but taste receptor cells are __________.
epithelial cells
___________ are single cells that contain a photosensitive pigment and a shading pigment that helps provide directional information by shading light coming from some directions.
eyespots
A polymodal sensory receptor encodes different modalities using labeled line processing.
false
Arthropods do not have external sensory structures because the hard exoskeleton prevents it.
false
Different sensory neurons use different types of action potentials to transmit information.
false
In vertebrates, each odorant receptor protein can bind only a single odorant.
false
Mechanoreceptors make use of G proteins to transduce mechanical signals into electrical ones.
false
Proprioceptors normally fire phasically.
false
Taste receptor proteins are always associated with G proteins.
false
The gustatory system can discriminate as many compounds as the olfactory system.
false
The vertebrate olfactory system can distinguish thousands of odorants through labeled line processing.
false
To focus on an object, the cornea must modify its shape to some extent.
false
Unicellular eukaryotes cannot respond to environmental stimuli.
false
Vertebrate tactile receptors are grouped into complex mechanosensory organs.
false
Weakly electric fish have organs to generate electrical discharge, but do not have electroreceptors.
false
It is generally held that ciliary photoreceptors are associated with invertebrates, while rhabdomeric photoreceptors are associated with vertebrates.
false (both can have both)
The vestibular, tympanic, and cochlear ducts of the mammalian inner ear are filled with a substance called perilymph.
false (only vestibular and tympanic, cochlear filled with endolymph)
In aquatic vertebrates, gustation always involves detecting sensations involved with
food (olfaction associated with food, predators, potential mates, and locations)
In both the ________ and _________ the overlying bipolar and ganglion cells are pushed to one side, allowing light to strike the photoreceptors without passing through several layers of neurons. This is where vision is sharpest.
fovea and visual streak
Stimulus intensity is normally coded by action potential __________.
frequency
When a sensory receptor is an afferent neuron, the membrane potential that is initiated by a stimulus is called a
generator potential
If the orientation of your ears were changed so that your right ear still faced forward but your left ear faced backward, how would your ability to locate the direction of an auditory stimulus change?
improved ability to distinguish front from back
Improving the resolving power of the compound eye would require
increase number of ommatidia or reduce the size of each ommatidium
Mechanoreceptors translate mechanical signals into electrical signals when pressure on the cell
induces a conformational change in ion channels, allowing ions to flow.
In response to a stimulus, a signal transduction pathway is initiated, which ultimately leads to the opening or closing of __________.
ion channels
Which eye structure constricts or dilates to control the amount of light that enters the eye?
iris
To help discriminate the location of a touch stimulus, neurons at the center of the receptive field can inhibit those at the edge, a process known as __________.
lateral inhibition
What are the three bones in the middle ear?
malleus incus stapes
Select the pair below that does not match.
mechanoreceptors- magnetic fields
The compound called __________ can stimulate cold-sensitive neurons.
menthol
In the vertebrate olfactory system, the olfactory receptor cells have one end in the olfactory epithelium, and the other end makes synapses with neurons in the __________ of the brain.
olfactory bulb
Compound eyes are composed of many __________.
ommatidia
The organ of the inner ear of mammals that contains the hair cells is called the __________.
organ of corti
The focal point is the
point where light waves converge after passing through the lens. (incoming light rays must converge at the retina, not behind it or in front in order to produce a clear image)
Sensory cells that respond to more than one class of stimulus are called __________ receptors.
polymodal
All sensory systems work in the same general way. They transduce an incoming stimulus into changes in membrane
potential
You are riding your bicycle over a very bumpy road, reading a street sign far ahead of you. Which sensory inputs are required to accomplish this task?
proprioceptors, visual inputs, inner ear
Odorant receptors are
proteins
________ is when the action potential frequency declines if the stimulus intensity is maintained at a constant level.
receptor adaptation
To generate an optimal visual image, the focal point must fall on the
retina
Which taste receptor does NOT use a G-protein-coupled receptor for activation?
salty
Merkel's disks are used by the visually impaired for reading Braille. One quality of the receptor that allows this is
small receptive field
In mammals, the circadian clock is located in the
suprachiasmatic nucleus.
What is the main difference between "on" and "off" region receptive fields?
the nature of the response of the bipolar cell to glutamate
Among vertebrates, taste buds share certain common features. Which of the following is FALSE?
they are single neurons TRUE: onion shaped, They have a pore that opens out to the surface of the body, and They have numerous microvilli on the apical surface.
A paramecium is capable of responding to
touch, chemicals, temperture
Bitter and sour tastes are generally associated with
toxic substances
Which of the following is one of the steps of sensory processing?
transduction of the signal, transmission of the signal to the integrating center, perception of the stimulus at the integrating center
There are two main types of mechanoreceptor proteins: epithelial sodium channels and __________.
transient receptor potential channels
A cup-shaped eye has improved discrimination in light direction and intensity over a flat sheet eye.
true
All vertebrates have an inner ear.
true
Bitter-taste receptors do not depolarize when activated.
true
Despite the great diversity of eye structure, there is surprising similarity at the molecular level in the development of eyes in all animals.
true
In Drosophila, each gustatory neuron appears to express only a single receptor protein.
true
In vertebrates, each odorant receptor cell expresses only a single kind of odorant receptor protein.
true
Many sensory receptor cells are epithelial cells.
true
Odor receptor proteins are always coupled to G proteins.
true
One similarity of all sensory receptors is that they must transduce some signal into a membrane potential.
true
Sensory processing requires the release of neurotransmitter.
true
The activity of hair cells in the vertebrate inner ear depends on a high concentration of extracellular K+.
true
The labeled line theory is based on the assumption that there is a discrete pathway from a sensory cell to the integrating center.
true
The minimum criterion for calling something an eye, rather than a photoreceptor, is the ability to detect the direction by which light has entered the organ.
true
Unlike taste receptor cells in vertebrates, invertebrate taste receptor cells are bipolar sensory neurons.
true
Vertebrate hearing and equilibrium require the activity of hair cells, so-called because of the cilia that extend from the apical end of each cell.
true
Terrestrial vertebrates detect pheromones using an organ called the __________ organ.
vomeronasal
The __________ law describes the logarithmic relationship between stimulus magnitude and perceived stimulus intensity.
weber-fechner