A myelin sheath is an insulating layer that is wrapped around an axon. In the peripheral nervous system, each myelin sheath is formed by an individual Schwann cell which wraps itself around the axon length. In the central nervous system, oligodendrocytes send out numerous processes (arms!) to wrap multiple axons. So myelin is actually just [...]
Chapter: Neuroscience
Neurotransmitters
Neurons communicate with each other by releasing chemical messengers called neurotransmitters. Neurotransmitters are found at the end of a neuron axon, called the presynaptic terminal. These chemicals are released in response to an electrical stimulation (the traveling action potential). Another neuron then detects the neurotransmitters by specific receptors at its postsynaptic membrane. Activation of these [...]