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27 Cards in this Set
- Front
- Back
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what is the function of Sense?
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to detect and send info to the CNS regarding internal and external environment
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what do Visceral afferents do?
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they detect information about the internal environment
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what types of information do visceral afferents detect?
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blood pressure
internal temperature CO2 concentration |
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does visceral afferent info reach consciousness?
why do we need them? |
no; they are necessary for maintaining homeostasis
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what are sensory afferents?
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axons that detect info re: outside temp and position in space (somatic),or vision, hearing, taste, or smell (special sense).
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what is a stimulus?
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the energy that impinges upon and activates a sensory receptor
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what are the 2 possible forms of sensory receptors?
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1. The specialized end of an afferent neuron that directly passes a change in potential along the neuron.
2. a seperate cell that releases a chemical to generate a change in potential of the afferent neuron. |
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what is stimulus transduction?
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the process where a stimulus (like light or tissue stretching) is transformed into electrical energy
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what is an adequete stimulus?
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the type of energy that normally stimulates a neuron, and does it best.
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what is the difference between a Receptor Potential and Generator Potential?
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Receptor Potentials occur when a SEPERATE cell from the neuron is stimulated and then causes ion channels to open.
Generator Potentials occur when a special membrane portion of the afferent neuron ITSELF recieves the stimulus and causes ion channels to open. |
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what is an example of a RECEPTOR potential?
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a ROD or CONE in the eye.
a seperate cell is stimulated by light, and releases a chemical messenger to diffuse across a synapse to chemical-messenger-gated channels in the afferent neuron. |
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What are two examples of GENERATOR Potentials?
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-Thermoreceptors
-Baroreceptors The stimulus acts right on the aff. neuron itself, and current - graded potential - flows from the initial membrane stimulated to where there are voltage-gated channels to activate. |
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How are Action Potentials generated by
-Receptor potentials -Generator potentials ? |
Receptor potentials cause a chemical to diffuse and activate/open chemical msngr-gated ion (Na+) channels.
Generator potentials cause charge to open voltage-gated Na+ channels. |
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What is "Adaptation"?
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a decrease in action potential generation with the same strength of stimulus.
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What type of receptors are slow or non-adaptive?
2 examples? |
Tonic receptors.
Pain receptors - meant to tell us when we're in danger.. Muscle-joint receptors - give information re; where our limbs are in space - if we forget, we'd fall over. |
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what are rapidly-adapting receptors called?
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phasic
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How do Phasic receptors work?
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example: putting on a watch.
You put on a watch and feel it initially, then immediately get used to the constant presence. - Stim remains Constant, but the receptor turns off. When you remove the watch, you feel it - that is the OFF-RESPONSE. |
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what are Phasic receptors really concerned with?
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stimulus INTENSITY -
PUT it on TAKE it off while it's on, you don't care. |
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what does a Pacinian corpuscle do?
what type of receptor is it? |
detects changes in pressure and vibration, proportional to how intense it is.
the neuron is wrapped in layers of connective tissue. when something presses on it, Na channels open and a generator potential is generated. When the pressure removes, an off-stimulus fires. PHASIC |
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What is the "Receptive Field"?
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the area within which the sensory neuron responds to sensory information
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what is acuity?
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one's ability to discriminate between senses. the smaller the receptive field, the more acute the sensation is.
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what is Receptor Density?
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the amount of neurons there are in a receptive field.
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How do you get the greatest Acuity?
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by having a very high density of receptors in a very small receptor field.
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what does the CNS Code of Information include?
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1. Stimulus intensity
2. Stimulus location 3. Stimulus Identity |
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how is a stimulus intensity increased or changed?
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a. Frequency - the greater NUMBER of generator potentials induced by a stimulus, the greater number of Action potentials will result.
b. Receptor Fields - the greater number of them for the same neuron type, the more intense of a sensation will be felt. |
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How is it that the CNS code of info tell you the LOCATION of a stimulus?
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Because everytime a neuron fires, it sends the SAME information from the SAME TYPE of stimulus
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How does the CNS code convey what TYPE of stimulus is firing the neuron?
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Because according to Muller's doctrine, a specific neuron will convey a specific type of info to the CNS
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