Neuronal communication Flashcards

(4 cards)

1
Q

Role of myelin sheath

A
  • Acts as an insulating layer which protects the axon
  • Speeds up the conduction of the impulse along the axon (100 m/s) as it leads to the impulse jumping over the nodes of Ranvier.
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2
Q

Types of sensory receptors

A
  • mechanoreceptors (for pressure and movement eg Pacinian corpuscle)
  • chemoreceptors (for chemicals eg olfactory receptors)
  • thermoreceptors (for temperature changes eg end-bulbs of Krause inside the mouth)
  • photoreceptors (for light eg cone cells)
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3
Q

What is a transducer?

A

The ability to convert a stimulus into a nervous impulse (generator potential).

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4
Q

How the Pacinian corpuscle acts as a transducer

A
  1. Sensory neurone is in its resting state as the Na+ channels are too narrow to allow Na+ to diffuse (Resting potential).
  2. Pressure is applied to the PC, which changes its shape, causing the membrane surrounding the neurone to stretch.
  3. Due to this, the Na+ channels widen and allow Na+ to diffuse into the neurone.
  4. The influx of positive ions changes the potential of the membrane (it becomes depolarised), which results in a generator potential.
  5. Generator potential then creates an action potential.
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