How are messages between synapses sent?

How are messages between synapses sent?

• A. Electrochemically
• B. Mechanically
• C. Photons
• D. Gravitationally

Answer: (A)

Messages between synapses are transmitted electrochemically. When an electrical signal, an action potential, arrives at the presynaptic terminal, it opens voltage-gated calcium channels. Calcium floods in and triggers vesicles filled with neurotransmitters to fuse with the presynaptic membrane and release their contents into the synaptic cleft. The neurotransmitters diffuse across the gap and bind to receptors on the postsynaptic membrane, changing its electrical state by opening ion channels or triggering internal signaling. This chemical signaling then converts back into an electrical response in the next neuron, propagating the signal. This isn’t done mechanically, by light (photons), or by gravity, so those options don’t fit. The key idea is that electrical activity in one neuron triggers chemical communication that then affects the next neuron’s electrical activity.

Messages between synapses are transmitted electrochemically. When an electrical signal, an action potential, arrives at the presynaptic terminal, it opens voltage-gated calcium channels. Calcium floods in and triggers vesicles filled with neurotransmitters to fuse with the presynaptic membrane and release their contents into the synaptic cleft. The neurotransmitters diffuse across the gap and bind to receptors on the postsynaptic membrane, changing its electrical state by opening ion channels or triggering internal signaling. This chemical signaling then converts back into an electrical response in the next neuron, propagating the signal.

This isn’t done mechanically, by light (photons), or by gravity, so those options don’t fit. The key idea is that electrical activity in one neuron triggers chemical communication that then affects the next neuron’s electrical activity.