5.1.3 Flashcards
(29 cards)
What are sensory receptors?
Groups of specialised cells that detect changes in the surroundings and convert them to neuronal signals.
What is the function of sensory receptors?
They act as transducers, converting one type of energy to chemical and then electrical energy.
Name an example of a photoreceptor.
Rods and cones in the eye.
What type of receptor are olfactory receptors?
Chemoreceptors.
What do Pacinian corpuscles detect?
Pressure and movement.
What are sensory neurons responsible for?
Carrying the action potential from a sensory receptor to the central nervous system.
What is the structure of a relay neuron?
They have many short dendrites and a short axon.
What is the role of motor neurons?
Carrying an action potential from the central nervous system to an effector.
What three main structures comprise neurons?
- Cell body
- Dendrons
- Axons
What is the resting potential of a neuron?
-70mV.
What maintains the resting potential?
The sodium-potassium pump.
What happens during an action potential?
The membrane is depolarised, generating an action potential.
What initiates the depolarization of a neuron’s axonal membrane?
A detected stimulus.
What is saltatory conduction?
The propagation of action potentials in myelinated neurons, jumping from node to node.
What is the all-or-nothing principle in action potentials?
The threshold value must be reached to generate an action potential.
What is a synapse?
A junction between two or more neurons.
What neurotransmitter is involved in cholinergic synapses?
Acetylcholine.
What role does acetylcholinesterase play in synaptic transmission?
It hydrolyses acetylcholine to prevent continuous action potentials.
What is temporal summation?
Combining several action potentials in the same pre-synaptic neuron.
What is spatial summation?
Combining action potentials arriving from several pre-synaptic neurons.
What is an inhibitory post-synaptic potential?
A potential that reduces the effect of summation and prevents an action potential.
How do synapses ensure unidirectional action potentials?
Only the pre-synaptic bulb contains vesicles of neurotransmitter.
What is the role of synapses in filtering signals?
They filter out low-level signals that cannot achieve summation.
What can happen to the pre-synaptic neuron after prolonged stimulation?
It can run out of vesicles, leading to habituation.
