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26 Cards in this Set
- Front
- Back
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Sensory Receptors - Sensation
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*connect to environment, stimulus activates receptor
*transduction converstion stimulus into physiological signal *brain interprets the physiolgical signal |
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Stimulus
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*environment
*change receptor in some way *each receptor binds to one stimulus vest |
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Sensation
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*brain always assumes stimulus is "normal"
*conscious senses - 5 senses *unconscious senses - position in space, BP, temp |
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Types of Receptors
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*parts of cells-no dendrites, modified receptor structures
*many produce AP's, many do not(produce receptor potentials) |
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Types of receptors
-Physical |
*physical chang either opens ion channel, or alters protein or smaller molecule
*touch, hair cell in ears, photo receptors, beroreceports |
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Types of receptors
-Chemical |
*taste, smell
*chemical must bind to receptor-ion channel *nocieptors *pain receptor -chemical/phys receptors |
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Receptor Potentials
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*generator potential
*local potential, graded potential *all receptor cells-short-only RP *in long-receptor potential-AP |
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Receptor Potentials
-Magnitude |
*in short cells, the RP causes release proportional to stimulus
*in long-# pf AP proportional to stimulus size |
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Receptor Potentials
-Frequency Dependence |
*to reach CNS-some afferent neuron must fire APs-brain interprets # of APs as size of stimulus
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Adaptation
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*decrease in # of APs despite a prolonged stimulus
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Adaptation
-phasic receptors |
*adapt over time-rate is variable
*many also have off response *touch-very fast *pain, BP-adapt more slowly |
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adaptation
-tonic receptors |
*do not adapt
*most tonic receptorts-truck muscles-posture |
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sensory specificity
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*brain interprets all stimuli as normal
*both stimulus and its site of action |
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Pain
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*nociceptors
*survival value, protection from harm *anticipation of pain activates pain areas of cortex |
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Pain
-fast pain |
*sharp, localized, passes quickly
*uses unmyelinated fibers-NT is substance P |
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Pain
-Substance P |
*ALWAYS associated with slow pain
*unique to pain pathway synapses *treatable with strongest analgesics. dont wait forever to start treatment |
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Pain
-Opioid Receptors |
*bind natural analgesics and outside analgesics-morphine
*open ion channels-> change membrane potential |
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Pain
-Opioid Receptors -Enkephalins/Endorphins |
*enkephalins-head. penta peptide. half life 25 seconds
*endorphins-periphery. larger peptides with enkephalin sequence. *morphine: 1/2 life of hours *sites:@ injury, in spinal cord, in brain. [these 3 will stop pain pathways] |
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Chemical Senses
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*molecular binding to receptors
*flavor:comb. of taste and smell |
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Taste
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*molecules must dissolved in saliva
*molecules must reach taste buds in order to be tasted |
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Taste Buds
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*receptors of taste pore
*tight junction ring cells at taste pore *epithilial cells-> basal cells-> receptor cells~(10 days) |
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Taste
-Neural Tracts |
*taste info
*thalamus-parietal lobe-"what youre eating" *limbic system-"like it" |
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Taste
-Taste receptors |
*sweet-sugars
*salty-sodium *acid/sour-H+ ions *bitter-quinine-(+) charge. (most sensitive, good detecting poisions) *umami-glutomate(amino acids) |
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Smell
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*receptors top of nasal cavity
*>1000 distinct smell receptors. >1% of human genome |
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Olfactory Receptors
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*covered with mucus-water soluble
*smelled-must be volatile enough to float to top *hydrophilic enough to dissolve in mucus *receptor-dendrites->replace every few weeks |
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Olfactory Adaptation
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*receptor tonic
*adaptation in CNS-brain can control what you detect *adaptation to one cell doesnt affect other smells *signal goes cortex(what) limbic system(like) |
