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33 Cards in this Set
- Front
- Back
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What advantage do myelinated axons provide? |
Myelinated axons have a faster conductions velocity than unmyelinated axons. |
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What accessory role does the outer ear (pinna) play in the auditory system? |
funnels sound into the ear canal |
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Fore each of the somatic and visceral stimuli listed below, which of the following receptor types is the appropriate transducer: mecahno-, chemo-, photo-, or thermoreceptors?
muscle length/tension, proprioception, pressure, inflation, distension, osmolarity, temperature, oxygen, glucose, pH |
Muscle length/tension, proprioception, pressure, inflation, distension, osmolarity = mechanoreception
Temperature = thermoreception Oxygen, glucose, pH = chemoreception |
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In Figure 10.5, what kinds of ion channel might open in neurons A and C that would depress their responsiveness: Na+, K+, Cl-, or Ca2+? |
K+ and Cl- channels in neurons A and C are probably opening and causing hperpolarization |
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How do sensory receptors communicat the intenisy of a stimulus to the Cns? |
Sensory neurons signal intensity of a stimulus by the rate at which they fire action potentials |
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What is the adaptive significance of irritant receptors that are tonic instead of phasic? |
Irritant recptos warn th body of dnger. If possible, the body should respond in some way that stops the harmful stimulus. THerefore, it is important that signals continue as long as the timulus is present, meaning the receptors shoudl be tonic rather than phasic. |
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What is the adaptiv advantage of a spinal reflex? |
rapid reaction |
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Rand the speed of signal transmission through the following fiber types, from fastest to slowest: (a) small diameter, myelinated fiber (b) large diameter, myelinated fiber (c) small diameter, unmyelinated fiber |
b,a,c |
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Your sense of smell uses phasic receptors, What other receptors adapt ongoing stimuli? |
There are many examples, including receptors for taste and touch |
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Create a map or diagram of the olfactory pathway from an olfactory sensory neuron to the olfactory cortex |
Olfactory sensory neuron > cranial nerve I > secondary neuron in olfactory bulb > olfactory tract > olfactory cortex in temporal lobe |
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Create a map or diagram that starts with a molecule from the environment binding to its odorant receptor in the nose and ends with neurotransmitter release from the primary olfactory neuron. |
See Figure 10.13 |
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The dendrites are which part of an olfactory sensory neuron? |
The knobby terminals of olfactory sensory neurons function as dendrites |
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Are olfactory neurons pseudounipolar, bipolar, or multipolar? |
bipolar |
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With what essential nutrient is the umami taste sensation associated? |
Umami is associate with ingestion of the amino acid glutamate |
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Map or diagram the neural pathway from a presynaptic taste cell to the gustatory cortex |
Presynaptic taste cell > primary sensory neuron through cranial nerves VII, IX, or X > medulla > thalamus > gustatory cortex in parietal lobe |
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What is a kilohertz? |
1000 Hz or 1000 waves per second |
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Normally when cation channels on a cell open, either Na+ or Ca2+ enters the cell. why does K+ rather than Na+ enter hair cells when their cation channels open? |
Endolymph has high [K+] and low [Na+] so the electrochemical gradient favours K+ movement into the cell |
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Map or diagram the pathways followed by a sound wave entering the ear, starting in the air at the outer ear and ending on the auditory cortex. |
See Figures 10.15, 10.17, and 10.21 |
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Why is somatosensory information projected to only one hemisphere of the brain but auditory information is projected to both hemispheres? |
Somatosensory information projects to the hemisphere of the brain opposite to the side of the body on which the signal originates. The location of sound is coded by the time a stimulus arrives in each hemisphere, so a signal to both hemispheres is necessary. |
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Would a cochlear implant help a person who suffers from nerve deafness? From conductive hearing loss? |
NOT help with nerve deafness NOT help with conductive hearing loss DOES help with sensorineural hearing loss |
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The stereocilia of hair cells are bathed in endolymph, which has a very high [K+] and low [Na+]. When ion channels in the stereocilia open, which ions move in which direction to cause depolarization? |
K+ entry into hair cells causes depolarization |
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Why does hearing decrease if an ear infection causes fluid buildup in the middle ear? |
the eardrum is unable to move freely and cannot transmit sound through the bones of the middle ear as efficiently |
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When dancers perform multiple turns, they try to keep their vision fixed on a single point. How does spogging keep a dancer from getting dizzy? |
the endolymph in the ampulla moves with each head rotation but then stops as the dancer holds the head still; this results in less inertia than if the head were continuously turning |
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What functions does the aqueous humor serve? |
> supports cornea and lens > brings nutrients to epithelial layer of cornea > removes wastes from epithelial layer of cornea |
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(a) Why does shining light into one eye cause pupillary constriction in both eyes?
(b) if you shine a light in the left eye and get pupillary constriction in the right eye but not the left eye, what can you conclude about the afferent path from the left eye to the brain? About the efferent pathways to the pupils? |
(a) the sensory pathway from one eye diverges to activate motor pathways for both pupils
(b) the afferent path and its integration must be functioning because there is an appropriate response on the right side. The motor pat to the left eye must not be functioning |
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Parasympathetic fibers constrict the pupils, and sympathetic fibers dilate them. The two autonomic divisions can be said to have ____________ effects on pupil diameter. |
antagonistic |
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If a person's cornea, which helps focus light, is more rounded than normal, is this person more likely to be hyperopic or myopic? |
the rays would converge more sharply. This causes the focal point to fall in front of the retina, so the person will be myopic |
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(a) static focal length, object moves closer; what happens to image distance Q?
(b) object moves closer, static image distance; what happens to focal length? Flatter or rounder lens? |
(a) image distance gets longer
(b) focal length decreases; rounder lens |
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(a) Explain how convex and concave corrective lenses change the refraction of light.
(b) Which type of corrective lens should be used for myopia, and why? Hyperopia? |
(a) convex: focus beam; concave: scatter beam
(b) myopia: concave; hyperopia: convex |
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Animals that see well in very low light lack a pigment epithelium and instead have a layer called the tapetum lucidum behind the retina. What property might this layer have that would enhance vision in low light? |
it reflects light, which enhances the amount of light hitting the photoreceptors |
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How is the difference in visual acuity between the fovea and the edge of the visual field similar to the difference in touch discrimination between the fingertips and the skin of the arm? |
In both the retina and the skin, the finest discrimination occurs in the region with the smallest visual or receptive fields |
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Macular degeneration is the leading cause of blindness in Americans over the age of 55. Impaired function of the macula causes vision loss in which part of the visual field? |
Damage to the macula, which surrounds the fovea, results in vision loss in the central portion of the visual field. Peripheral vison remains unaffected |
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Why is our vision in the dark in black and white rather than in colour? |
only rods, not cones, are sensitive enough to be stimulated by such low levels of light |
