Chemical Messengers Flashcards
What are action potentials transmitted along?
Axons to specialized regions called synapses
What separates the presynaptic nerve ending from the postsynaptic component?
A small gap called the synaptic cleft
What are the chemical messengers called that transmit signals across the synaptic gap?
Neurotransmitters
What are neurotransmitters stored in at the endings of axons?
Tiny spherical bags called synaptic vesicles
What triggers the release of neurotransmitters from synaptic vesicles?
The arrival of an action potential leading to the opening of ion channels allowing Ca++ entry
What term describes the process when neurotransmitters diffuse across the synaptic cleft?
Synaptic transmission
What happens to synaptic vesicles after they release neurotransmitters?
They reform and are refilled with neurotransmitter
What is the role of glial cells in the synaptic cleft?
To clear chemical messengers and recycle neurotransmitters
What is the effect of neurotransmitter attachment to ionotropic receptors?
Opens ion channels allowing positive ions to enter, leading to excitation
What is an excitatory post-synaptic potential (epsp)?
A shift in membrane potential from -70 mV to a value closer to 0 mV
What are the two main inhibitory neurotransmitters?
- GABA
- Glycine
What is an inhibitory post-synaptic potential (ipsp)?
A change in membrane potential opposing depolarization
How quickly does synaptic transmission occur?
In less than 1/1000 of a second
What triggers the release of the neurotransmitter glutamate?
Excitation of neurons
What role do metabotropic receptors play in neuronal signaling?
They modulate biochemical processes without initiating action potentials
What neurotransmitter is known to act on both ionotropic and metabotropic receptors?
Acetylcholine
Where are noradrenaline neurons primarily located?
In the locus coeruleus (LC)
What is the function of noradrenaline in the brain?
To organize responses to novelty and stress
What is the primary excitatory neurotransmitter in the brain?
Glutamate
True or False: The effects of neuromodulation are slower and longer-lasting than those of excitatory and inhibitory transmitters.
True
Fill in the blank: The binding of neurotransmitters to metabotropic receptors is similar to using a _______.
Key
What is the main function of G-proteins in metabotropic receptor signaling?
To bridge the receptor to intracellular enzymes affecting cell metabolism
