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44 Cards in this Set
- Front
- Back
3 classifications of sensory receptors |
1. type of signal they transduce 2. type of info sent to brain 3. Origin of information |
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Subclassifications of type 1 (type of signal) |
1. Chemoreceptors: chemicals in environment / blood 2. Photoreceptors: light 3. Thermoreceptors: cold /heat 4. Mechanoreceptors: mechanical deformation 5. nociceptors: pain |
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subclassifications of type 2 receptors (info delivered to brain) |
1. proprioceptors: sense of body position 2. cutaneous receptors: touch, pressure, heat, cold, pain 3. special senses |
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subclassifications of type #3 receptors (origin of info) |
exteroceptors and interoceptors |
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Phasic vs tonic receptors |
Phasic: fast adapting; burst of activity when stimulus is first applied tonic: maintains high firing as long as stimulus is applied (pain) |
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Law of Specific Nerve Energies |
Information from any given nerve fiber will only be experienced as one stimulus type ex: punch to the eye is experienced as a flash of light ex: paradoxical coldness |
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Receptor potential |
similar to EPSPs; graded response |
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Receptive fields |
size depends on density on receptors; small receptive fields = higher density = greater tactile acuity |
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Lateral inhibition |
receptors most strongly stimulated inhibit neighboring receptors ; results in sharpening of sensation ; occurs in CNS |
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Explain different cutaneous receptors |
Touch and pressure: merkel's discs; meissner's corpuscles; pacinian corpuscles; ruffini corpuscles capsaicin receptors: heat and capsaicin |
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Gustatory receptors |
taste buds located on papillae of tongue; papillae types: fungiform, circumvallate, foliate |
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5 categories of taste and chemicals they are sensitive to |
Salty: Na+ ion channel Sour: H+ ion channel Sweet: Sugar; G-proteins / 2nd messenger Umami: Glutamate; G-proteins / 2nd messenger Bitter: Quinine; G-proteins / 2nd messenger |
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Olfaction receptors |
Olfactory apparatus; bipolar neurons; sustentacular cells and basal stem cells |
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Olfaction process |
G-protein receptors; 1. Odor binds; activates adenosine cyclase; leads to cAMP and phosphate 2. cAMP opens Na+ and Ca2+ channels 3. Produces a graded Depolarization ; stimulates AP |
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Structures / functions of vestibular apparatus |
Otolith organs; utricle and saccule // linear acceleration Semicircular canals ; rotation acceleration |
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Depolarization vs. hyperpolarization of hair cells |
Depolarization: stereocilia bend toward kinocilium; K+ influx and NT release Hyperpolarization: stereocilia bend away from kinocilium |
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Specialized epithelium of otolith organs |
Macula |
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Explain rotational acceleration |
Semicircular canals; endolymph circulates, pushing cupula and bending hair cells |
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Vestibular nystagmus |
Jerky eye movement due to eye moves being opposite of spinning direction; after spinning stops, intertia causes cupula to bend and eye movements persist |
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Explain sound transmission |
Vibrations from oval window displace perilymph in Scala vestibuli; vibrations then pass to scala tympani and leave inner ear through round window ; soundwaves transmitted through perilymph displace basilar membrane |
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How does sound frequency affects where sound goes? |
High frequency: travels toward base of cochlea Low frequency: travels toward apex of cochlea |
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Explain how we hear |
Sounds enter cochlea duct and hair cells bend; K+ channels open leading to Depolarization ; glutamate is released which stimulates sensory neurons |
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Describe place theory of pitch |
Hair cells located on different places of basilar membrane respond to different frequencies of sound ; outer hair acts as an amplifier for cochlea |
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Explain sound localization |
Interaural time difference: difference in time of arrival of sound in each ear Interaural intensity difference: difference in loudness of sound in each ear |
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Conduction deafness |
Sound waves aren't conducted properly; affects all hearing frequencies. causes: earwax, fluid in middle ear, otosclerosis treatment: hearing aids |
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Sensorineural / perceptive deafness |
Nerve impulses aren't conducted from choclea to auditory cortex ; may only impair certain frequencies causes: damaged hair cells (noise induced), damaged nerve, age (presbycusis) treatment: cochlear implants |
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Describe pathway of light through eye |
1. Cornea 2. Anterior chamber 3. Pupil 4. Lens 5. Vitreous chamber 6. Retina |
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Explain pupils in dim light vs bright light |
Dim light: pupils dilate by contraction of radial muscles via sympathetic stimulation Bright light: pupils constrict by contraction of circular muscles via parasympathetic stimulation |
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Explain how real images look in light refraction |
inverted, upside down, smaller |
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Describe lens accommodation for distant and near vision |
Distant: ciliary muscles relax, sensory ligaments taut, lens thins and flattens Near: ciliary muscles contract, suspensory ligaments relax, lens thickens and rounds |
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Presbyopia |
Loss of lens accommodation with age ; lens can't thicken for near vision |
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Emmetropia / myopia / hyperopia /astigmatism |
Emmetropia: normal vision Myopia: nearsighted ; cause is elongated eyeball; treatment is concave lenses Hyperopia: farsighted; cause is shortened eyeball; treatment is convex lenses Astigmatism: light focuses as lines instead of points on retina ; cause is asymmetry of cornea; correction is cylindrical lenses |
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Two layers of retina |
1. pigmented layer 2. neural layer - photoreceptors; bipolar, horizontal, and amacrin cells; ganglion cells |
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difference between rods versus cones |
Rods: dim light, peripheral vision cones: detailed, color vision |
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What protein do rods contain that causes a bleaching reaction |
rhodopsin |
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explain visual cycle of retinal |
1. light adaptation from dim light to bright light 2. rhodopsin is made of opsin and retinal (11 - cis - retinal) 3. in response to light, retinol is converted to all- trans- retinol and dissociates from opsin (bleaching reaction) |
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Explain electrical activity of retinal cells in the dark |
1. photoreceptors depolarize and inhibitory neurotransmitters are released 2. bipolar neurons are hyperpolarized and inhibited 3. no stimulation of ganglion cells leads to no signal in the brain |
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explain electrical activity of retinal cells in light |
1. photo receptors are hyperpolarized and inhibited 2. bipolar cells depolarize and release glutamate 3. ganglion cells depolarize and send action potentials to brain 4. brain perceives light |
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describe the three types of cones in trichromatic vision |
1. s: shortwave; blue 2. M: medium wavelength; green 3. L: long wavelength; red |
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define the three different types of color blindness |
1. Deuteranopia: absence of M cones 2. protonopia: absence of L cones 3. tritonopia: absence of S cones |
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explain visual sensitivity |
sensitivity is convergence of many rods onto a single bipolar cell and many bipolar cells onto a single ganglion cell ; increases light sensitivity |
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explain visual fields |
right side is projected onto left side of retina, left side is projected onto right side of retina crossover at optic chiasma |
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Describe neural pathway for vision |
1. retina/ganglion cells 2. optic nerve 3. optic chiasma: information from lateral portion of retina stays on the same side, but information from medial portion of retina crosses 4. optic tract 5. lateral geniculate nucleus/thalamus 6. striate cortex / occipital lobe |
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describe saccadic eye movement, smooth pursuit movements, and vergence movements |
1. Saccadic eye movement: high velocity movements that keep the image focused on the fovea Centralis 2. smooth pursuit movements: match the speed of a moving object 3. vergence movements: allows both eyes to converge so an image is at fovea of both eyes |