14.4 receptors Flashcards
what do corpuscles respond to?
changes in mechanical pressure
features of sensory neurones
- specific to a single type of stimulus
- produces a generator potential by acting as a transducer
what is a transducer?
converts one form of energy into another
what do Pacinian corpuscles transduce?
mechanical energy -> generator potential (electrical energy)
where do Pacinian corpuscles occur?
- deep in the skin e.g. fingers, soles of feet, external genitalia
- joints
- ligaments
- tendons
what do Pacinian corpuscles in the joints, ligaments and tendons allow?
enable the organism to know which joints are changing direction
where are Pacinian corpuscles found?
end of sensory neurones
how does stimulation of a Pacinian corpuscle cause an action potential?
- deform stretch mediate channel
- Na+ channels open
- Na+ diffuses in
rod cells
- rod- shaped
- greater number than cone cells
- more at the periphery of the retina, absent at the fovea
- give poor visual acuity
- sensitive to low- intensity light
- 1 type
cone cells
- cone- shaped
- fewer numbers than rod cells
- few at the periphery of the retina, concentrated at the fovea
- give good visual acuity
- not sensitive to low- intensity light
- 3 types
what is retinal convergence?
number of rod cells connected to a bipolar cell
what sort of summation do rod cells show?
spatial summation
draw a Pacinian corpuscle
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