Final answer:
A synapse is a slight gap between nerve cells, known as the synaptic cleft, where neurotransmitters are released from one neuron and received by another, facilitating communication between cells. Such gaps are crucial for efficient neuronal signaling and can occur between various parts of neurons and other cells.
Step-by-step explanation:
A synapse is best described as option C: a slight gap between nerve cells. This gap, also known as the synaptic cleft or synaptic gap, is essential for the process of neurotransmission where signaling molecules called neurotransmitters are released by the axon terminal of a neuron, and bind to the receptors on the dendrites of another neuron. The synaptic cleft is relatively small, about 20 nm wide, which allows for the rapid raise and lower of neurotransmitter concentration, facilitating efficient communication between neurons or between neurons and other cell types.
During synaptic transmission, information is passed from the presynaptic neuron to the postsynaptic neuron, which may be another neuron, muscle cell, or gland cell. Neurons are commonly both presynaptic and postsynaptic as they can send and receive signals. There are two main types of synapses: chemical and electrical, with chemical synapses being more common, involving the release of neurotransmitters across the synaptic cleft.