Neuronal Communication Flashcards
What are neurones?
Specialised cells that conduct nerve impulses
What do sensory neurones do?
Transmit action potentials from sensory receptors to other neurones
What do relay neurones do?
Transmit action potentials from sensory neurones to motor neurones
What do motor neurones do?
Transmit action potentials from the Central Nervous System or relay neurones to muscle or glands
What do reflexes bypass?
The central nervous system
Where is the cell body located on a sensory neurone?
in the middle of the dendron and axon
Where is the cell body located on a motor neurone?
At the dendron end
What direction does an impulse travel along a neurone?
From the dendron to the axon
What does myelin act as?
An electrical insulator, speeding up the conduction of action potentials along an axon
Where is myelinated?
Along the long axons within the nervous system (white matter)
Where is non-myelinated?
In neuronal body cells and dendrites (grey matter)
How do action potentials travel when myelinated?
Action potentials jump along axons at nodes of Ranvier by saltatory conduction
Does myelination make the axon wider or narrower?
Wider
Does myelination make transmission faster or slower?
Faster
How do action potentials travel along non-myelinated neurones?
Occur throughout the whole length of the axon
Between each adjacent Schwann cell there is a small gap known as?
a node of Ranvier
What is the stimulus of a mechanoreceptor?
Pressure and movement
What is the stimulus of a chemoreceptor?
Chemicals
What is the stimulus of a thermoreceptor?
Heat
What is the stimulus of a photoreceptor?
Light
Give an example of a mechanoreceptor
Pacinian corpuscle - detects pressure
Give an example of a chemoreceptor
Olfactory receptor - detects smells
Give an example of a thermoreceptor
End-bulbs of Krause
Give an example of a photoreceptor
Cone cell - detects different light wavelengths
Example of a sense organ with a mechanoreceptor
Skin
Example of a sense organ with a chemoreceptor
Nose
Example of a sense organ with a thermoreceptor
Tongue
Example of a sense organ with a photoreceptor
Eye
Define transducer
Converts stimuli (light, heat, pressure) into a nervous impulse (generator potential)
Where are Pacinian corpuscles located?
Deep within your skin
What is the special type of sodium channel called in a Pacinian corpuscle?
Stretch-mediated sodium channel
What happens when a stretch-mediated sodium channel changes shape?
Their permeability to sodium also changes
