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94 Cards in this Set
- Front
- Back
Characteristics of Sensory Receptors |
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what is a sensory receptor? |
Specialized nerve cell that is designed to respond to a specific sensory stimulus |
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Give examples of sensory stimulus |
touch, pressure, pain, light, sound, position in space and vibration |
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what are 3 types of sensory receptors? |
1.exteroceptors 2.interoceptors 3. proprioceptors |
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What are the functional categories according to the type of signal they transduce |
-chemoreceptors: sense chemicals in the environment (taste, smell) or blood -photoreceptors: sense light -thermoreceptors: respond to cold or heat -mechanoreceptors: stimulated by mechanical deformation of the receptor (touch, hearing) |
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cutaneous receptors |
respond to pain, temperature, pressure, vibration, and discrimative touch |
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Nociceptors |
pain receptors that depolarize when tissues are damaged
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what type of stimuli does nociceptors include |
-heat, cold, pressure, or chemicals
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what are they main neurotransmitters foe Nocicpetors? |
-glutamate and substance P are the main neurotransmitters |
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How can the preception of pain be enhanced? |
by emotiond, concepts, and expectations |
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what are prorioceptors? |
found in muscles, tendons, and joints. provide a sense of body position and allows fine muscle control |
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What are the 5 special sense receptors? |
1. visual 2. olfactory 3. auditory 4. gustatory 5. equilibrium |
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Receptors cannot be classified by the origin of the information
TRUE or FALSE |
FALSE, receptors can be classified by the origin of the information (exteroceptors, interoceptors)
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What are exteroceptors? give examples |
respond to stimuli from outside the body; includes cutaneous receptors and special senses. -examples: visual, auditory, tactile, gustatory, and olfactory
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What are interoceptors: |
respond to internal stimuli; found in organs; monitor blood pressure, pH, and oxygen concentrations |
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Receptors can not be categorized based on how they respond to stimulus
TRUE or FALSE |
FALSE, receptores can be categorized on how they respond to stimulus |
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Define Phasic Receptor |
responds with a a burst of activity when stimulus is first applied but quickly adapt to the stimulus be decreasing response |
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what kind of changes can Phasic Receptors alert us to? |
environmental changes |
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does phasic receptors allow sensory adaptaion? |
yes phasic receptors do allow for sensory reception |
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what is sensory adaptation |
cease to pay attention to constant stiumli |
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what are some examples of phasic receptors |
smell, touch, temperature |
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what is a tonic receptors |
they maintain a high firing rate as log as the stimulus is applied |
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what is an example of a tonic receptor |
pain |
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is tonic receptor fast or slow adapting? |
slow adapting |
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is phasic receptor fast or slow adapting? |
fast adapting |
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what is paradoxical cold |
pereception of cold at different temperatures |
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What is a generator potential? |
stimuli that produces depolarization |
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what do receptors behave like? |
dendrites of neurons |
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what is pacinian corpuscle |
-one of the four major types of mechanoreceptors. -They are nerve endings in the skin responsible for sensitivity to vibration and pressure. |
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what is a generator (receptor) potential? |
type of graded potential, is the transmembrane potential difference of a sensory receptor |
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increasing the ________increases the magnitude of the generator potential until threshold is met and an ______________ occurs |
pressure, action potential |
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Generator (receptor) Potential is a graded response.
TRUE or FALSE |
TRUE |
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what happens with the generator potential in Pacinian corpuscles which are phasic receptors, if pressure is maintained |
generator is diminished |
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how does the generator potential in tonic receptors relate to stimulus intensity? |
the generator is proportional to the intensity of the stimulus. |
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in tonic receptors how does the increased intensity effect frequency of action potentials? |
the frequency of action potentials increases with the intensity, after the threshold is reached |
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define Cutaneous Receptors |
type of sensory receptor found in the dermis or epidermis. They are a part of thesomatosensory system. -Cutaneous receptors include e.g. -cutaneous mechanoreceptors, -nociceptors (pain) -thermoreceptors (temperature). |
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what are naked dendrites of sensory neurons? |
pain, cold, and heat receptors |
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what kind of receptors have a special structure arounf their dendrites? |
touch and pressure receptors |
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give examples of touch and pressure receptors (mechano-receptors) |
1. Merkel's disks 2. Meissner's corpuscles 3. Pacinian corpuscles 4. Ruffinin corpuscles
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what is the structure, sensation, and location of:
Free nerve endings |
-unmyelinated dendrites of sensory neurons -light touch; hot; cold;nocicpetion (pain) -around harid follicles; throughout skin |
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what is the structure, sensation, and location of:
Merkel's discs |
-expanded dendritic endings associated with 50-70 specialized cells -sustained touch and indented depth -base of epidermis (stratum basale)
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what is the structure, sensation, and location of:
Ruffini Corpuscles (endings) |
-Enlarged dendritic endings with open, elongated capsule -skin stretch -deep in dermis and hypodermis
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what is the structure, sensation, and location of:
Meissner's corpuscles |
-dendrites encapsulated in connective tissue -changes in texture; slow vibrations -upper dermis (papillary layer)
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what is the structure, sensation, and location of:
Pacinian Corpuscles |
-dendrites encapsulated by concentric lamellae of connective tissue structures -deep pressure; fast vibrations -deep in dermis |
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Characteristic of Merkel's discs |
indentation |
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Characteristic of Root hair plexus |
light brushing |
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Characteristic of Pacinian Corpuscle |
vibration; deep pressure |
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Characteristic of Meissner's Corpuscle |
changes in texture |
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Characteristic of Free nerve ending |
touch, pain, hot, cold |
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Characteristic of Ruffini endings |
Skin stretch |
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define cold receptors |
stimulated by cold and inhibited by warm |
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do more receptors respond to cold or hot? |
there are many more receptors that respond to cold than to hot |
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where are cold receptors located? |
close to the epidermis |
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what else can cold receptors respond to? |
menthol |
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what is the temperature range of response for cold receptors? |
8-28 degrees Celcius |
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what kind of channel can cold receptors serve as |
as an ion channel for sodium and calcium- a transient receptor potential (TRP) |
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Define warm receptors |
excited by warming and inhibited by cooling |
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where are warm receptors located?? |
deeper in the dermis |
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Warm receptors are the same as receptors that detect painful heat
TRUE or FALSE |
FALSE, they are different |
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define hot receptor |
receptor that experiences pain by a hot stimulus is sensed by a peical nociceptor, called a capsaicin receptor |
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what kind of channel can a hot receptor serve as |
serves as an ion channel for sodium and calcium- a TRP channel |
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what temperature is the hot receptor activated? |
43 degrees celcius of higher |
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Nociceptors can by _______or _________ |
myelinated neurons, unmyelinated neurons |
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sudden sharp pain is transmitted by what type of neurons |
myelinated neurons |
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dull persistant pain is transmitted by what type of neurons? |
unmyelinated neurons |
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how can Nociceptors be activated? |
-chemicals released by damaged tissue (ATP) -pH change -mechanical stimuli |
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how is acute itch stimulated? |
by histamine release form mast cells and basophils |
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define mast cells |
chemicals are very irritating and cause itching, swelling, and fluid leaking from cells |
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define basophils |
type of white blood cell (leukocyte) with coarse, bluish-black granules of uniform size within the cytoplasm. |
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what kind of itch it stimulated by other chemicals and does not respond to antihistamines |
chronic itch |
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what stimulates unmyelinated sensory axons to the spinal cord |
Receptors |
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what steps does the neural pathways from the Somatesthetic Sensations for pressure receptors and proprioceptors |
1. First they are carried by a large myelinated fibers that ascend the dorsal columns of the spinal cord on the ipsilateral side
2. Then they synapse in the medulla oblongata
3. The seond tier of neurons cross sides as they ascend the medial lemniscus to the thalamus, where they synapse
4. Third-order neurons go to the postcentral gyrus in the parietal lobe (somatosensroy cortex) |
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what steps does the neural pathways from the Somatesthetic sensations for heat, cold, and paint receptors |
1. First carried into spinal cord by thing myelinated and unmyelinated neurons to the lamina of the dorsal gray horns
2. Synapse within spinal cord onto second-order neuron
3. Cross sides and ascend lateral spinothalamic tract
4. Synapse on thrid-order neurons in thalamus and continue to the post central gyrus |
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When does emotional response to pain occur? |
when information is sent from the thalamus to the anterior is sent from the thalamus to the anterior cingulate gyrus (part of the limbic system) |
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Define referred pain |
when the brain may interpret heart pain as arm pain, or gallbladder pain as back pain |
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What is the receptive field? |
the area of skin that when stimulated, changes the firing rate of a neuron |
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The size of the receptive field depends on what? |
the density of receptors in that region of skin |
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There are alot of receptors in the back and legs so the receptive fields are small
TRUE or FALSE |
FALSE, they are large because there are few receptors |
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There are few receptors in the fingertips, so the receptive fields are large
TRUE or FALSE |
FALSE, there are many receptors in the fingertips, so the receptive fields are small |
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The more receptors the _______the field, the ________the area of the somatosensory cortex |
smaller, larger |
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greater tactile acuity - sharpness of the sensation=? |
a small reeptive field |
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How can receptive fields be measured? |
by seeing at what distance a person can perceive two separate points of touch |
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what does two-point touch threshold measure? |
tactile acuity |
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What is the lateral inhibition? |
Receptors where touch is the strongest are stimulated more than areas where touch is lighter |
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Receptors that are most strongly stimulated _____those around them. What does this allow? |
inhibit, this allows us to perceive well-defined sensations at a single location instad of a "fuzzy" border |
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Where does the lateral inhibition occur? |
in the Central Nervous System |
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The ability to not notice the smell of fish from the previous day is due to tonic receptors.
true or false |
false,Sensory adaptation is due to phasic receptors that give a burst of firing when the stimulus starts and then again when it ends. See section 10.01 of the text for more information. |
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Receptive fields that do not receive a strong stimulation will help sharpen the sensation by |
lateral inhibition
Those receptors that are on the edges of the stimulation will have their stimulation reduced which will strengthen the stimulus to those receptors that are more central, increasing their acuity. See section 10.02 of the text for more information. |
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How many neurons are in the somatesthetic pathway from the skin to the postcentral gyrus? |
3, Sensory pathways will generally have three neurons. The first neuron runs from the receptor to the spinal cord. The second neuron runs through the spinal cord to the thalamus. The third neuron runs from the thalamus to the somatesthetic cortex on the postcentral gyrus. See section 10.02 of the text for further study. |
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When a generator (receptor) potential reaches threshold, an action potential will be produced.
true or false |
true, An action potential will be produced once the receptor potential has reached threshold. See section 10.01 of the text for more information. |
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The greater the receptor density, the greater the sensory acuity.
true or false |
true
The more receptors present in a particular area, the better the sharpness (acuity) of the sensation. The finger tips have many more touch receptors than the upper arm, so more detailed touch information will be transmitted from the finger tips than from the upper arm. See section 10.02 of the text for more information. |
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Sensations of heat, cold, and pain travel to the spinal cord, cross to the contralateral side, and ascend to the thalamus by way of the ______ tracts. |
lateral spinothalamic
Sensations of heat, cold, and pain travel to the spinal cord, cross to the contralateral side, and ascend to the thalamus by way of the lateral spinothalamic tracts. See section 10.02 of the text for more study on this topic. |
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Match the stimulus example to the type of sensory receptor. 1.chemorceptor touch 2.photoreceptor carbon dioxide 3.mechanoreceptor glow stick 4.nociceptor a burn 5. thermoreceptor open oven |
1. carbon dioxide 2.glow stick 3. touch 4. a burn 5. an open oven |
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When a stimulus is applied to a sensory ending, a graded response called a _______ potential is produced. |
generator |