Sensory Receptors : Body Sensation Flashcards
<p>What are sensory receptors?</p>
<p>Sensory receptors are nerve endings with specialised non-neural structures</p>
<p>What do sensory receptors do?</p>
<p>Sensory receptors are transducers that convert different forms of energy into frequency of action potentials, informing the CNS about the internal and external environment</p>
<p>What is sensory modality?</p>
<p>Sensory modality is the stimulis type activating a receptor</p>
<p>What is an adequete stimulis?</p>
<p>An adequete stimulis is the type of energy to which a receptor normally responds</p>
<p>What can you say about sensory receptors being activated by many stimuli?</p>
<p>Sensory receptors are highly sensitive to one kind of stimuli, but may be activated by another</p>
<p>What are some different types of receptors?</p>
<p>Some different types of receptors are:</p>
<p>Mechanoreceptors (mechanical stimuli like touch)</p>
<p>Proprioreceptors (informations about position in space)</p>
<p>Nociceptors (pain)</p>
<p>Thermoreceptors (cold and warmth)</p>
<p>Chemoreceptors (chemical change)</p>
<p>Photoreceptors (responds to the wavelength of light)</p>
<p>What does sensory receptor transduction involve?</p>
<p>Sensory receptor transduction involves ion channels opening and closing, adequete stimuli generates a graded potential</p>
<p>What is membrane deformation?</p>
<p>Membrane deformation is adequete stimuli in mechanoreceptors and proprioreceptors</p>
<p>What does membrane deformation activate?</p>
<p>Membrane deformation activates stretch sensitive ion channels, causing a local graded potential</p>
<p>What happens when the graded potential reaches threshold?</p>
<p>When the graded potential reaches threshold an action potential is fired</p>
<p>What is frequency coding of stimulis intensity?</p>
<p>This means a larger stimuli produces a larger graded potential which produces higher frequency of action potentials fired</p>
<p>What does the number of receptors activated in an area reflect?</p>
<p>The number of receptors activated in an area reflects the stimulis intensity</p>
<p>What are some contrasts in the action potentials of some mechanoreceptors?</p>
<p>In some mechanoreceptors if the stimuli persists then action potentials are constantly fired</p>
<p>In others, action potentials are only fired when something changes</p>
<p>What is adaptation?</p>
<p>Adaptation is when some mechanoreceptors adapt to a maintained stimulus and only signal change</p>
<p>What are the two different kinds of adapting receptors?</p>
<p>The two different kinds of adapting receptors are:</p>
<p>Rapidly/moderately adapting receptors (fire AP at change)</p>
<p>Slowly adapting receptors (constantly fires AP)</p>
<p>Why do nocioreceptors not adapt?</p>
<p>Nocioreceptors do not adapt because they are free nerve endings</p>
<p>What is the pacinian corpuscle and how does it work?</p>
<p>The pacinian corpuscle is a mechanoreceptor:</p>
<ol> <li>Mechanical stimuli deforms capsule</li> <li>Stretches nerve endings and opens ion gated channel</li> <li>Na+influx causes graded potential</li> <li>Action potential generated and fired</li></ol>
<p>What does rapid adaption occur?</p>
<p>Rapid adaption occurs because the fluid redistributes in the capsule and removes mechnical stress from the nerve ending</p>
<p>How do nerve endings respond without a capsule?</p>
<p>Without a capsule, bare nerve endings have no adaptation and fire constant action potentials</p>
<p>What are receptive fields?</p>
<p>Receptive fields are somatic sensory neurons activated by stimuli in a specific area</p>
<p>What posseses receptive fields?</p>
<p>Sensory receptors posses receptive fields</p>
<p>What does our ability to determine two points on the skin depends on?</p>
<p>Our ability to determine two points on the skin depends on:</p>
<p>Receptive field size</p>
<p>Neuronal convergence</p>
<p>What is our ability to determine two points on the skin tested by?</p>
<p>The two point discrimination test</p>
<p>What is neuronal convergence?</p>
<p>Neuronal convergence is when multiple pre-synaptic neurons input a smaller number of post synaptic neurons</p>
<p>What do sensory neurons with neighbouring receptive fields show?</p>
<p>Neighbouring neurons with receptive fields show neuronal convergence</p>
<p>What does neuronal convergence allow?</p>
<p>Neuronal convergence allows sub threshold stimuli to summate at the secondary neuron to generate an action potential</p>
<p>What leads to an insensitive area?</p>
<p>Neuronal convergence and a large receptive field leads to an insensitive area</p>
<p>What is an example of a sensitive and insensitive area?</p>
<p>The lips are sensitive</p>
<p>The back is insensitive</p>
<p>What is acutiy?</p>
<p>Acuity is the ability to locate a stimulis on the skin and differentiate it from another closeby</p>
<p>When does high acuinty occur?</p>
<p>High acuinity happens when lots of signals from an area goes to the brain, low acuinity happens when less go</p>
<p>What is lateral inhibition?</p>
<p>Lateral inhibition is when information from a neuron from a sensory receptor at the end of a stimuli is inhibited by information from the centre</p>
<p>What does lateral inhibition allow us to do?</p>
<p>Lateral inhibition allows us to precisely locate stimulis</p>
<p>What is tonic level of firing?</p>
<p>Tonic level of firing is a base level of nerve impulses firing when nothing is going on</p>
