5.1.3: Neuronal Communication Flashcards
What do sensory neurones carry?
Electrical impulses from the sensory receptor cell to the relay neurone
They may also send impulses to the motor neurone and the brain.
What is the structure of sensory neurones?
Long dendron and an axon
The dendron carries impulses to the cell body, and the axon carries impulses to the next neurone.
What do relay neurones do?
Carry impulses between the sensory and motor neurones
They have multiple short axons and dendrons.
What is the role of motor neurones?
Carry impulses from a relay or sensory neurone to the effector
Effectors can be muscles or glands.
How are motor neurones structured?
One long axon and multiple short dendrons
What do sensory receptors do?
Detect a stimulus and convert it into electrical nerve impulses
They are known as transducers.
What type of stimulus do photoreceptors detect?
Light
What type of stimulus do thermoreceptors detect?
Heat
What type of stimulus do mechanoreceptors detect?
Pressure
What is the function of the Pacinian corpuscle?
Respond to pressure changes
It is located deep in the skin, mainly in fingers and feet.
What is the structure of a Pacinian corpuscle?
A single sensory neurone wrapped with layers of tissue separated by gel
What kind of channels do sensory neurones in the Pacinian corpuscle have?
Stretch-mediated sodium channels
What happens to sodium ion channels in the resting state?
They are too narrow for sodium ions to diffuse into the sensory neurone
This helps to maintain the resting potential.
What occurs when pressure is applied to the Pacinian corpuscle?
Stretch-mediated sodium ion channels deform and widen
This allows sodium ions to diffuse in, establishing a generator potential.
