Synapses
Next, we'll talk about synapses, the specialized areas where neurons communicate with one another.
1) Start with this video:
2) Read this article for some historical context: History of Neuroscience - Charles Scott Sherrington
3) Watch this video for a quick refresher:
4) Finally, answer these questions to test your understanding:
1. Which component of a synapse below is where neurotransmitters are typically released FROM?
- A. presynaptic membrane
- B. synaptic cleft
- C. postsynaptic membrane
- D. gap junction
Show Answer
Correct answer: A
Neurotransmitters are typically released FROM the presynaptic membrane and INTO the synaptic cleft. They typically bind to receptors on the postsynaptic membrane. Gap junctions (the last answer choice) are regions where neurons communicate at electrical synapses (which don't involve neurotransmitters).
2. This is the most common type of synapse in the human nervous system:
- A. axoaxonic
- B. dendrodendritic
- C. axosomatic
- D. axodendritic
Show Answer
Correct answer: D
Synapses can form between many different parts of neurons, but those that form between the axon terminals of one neuron and the dendrites of another—known as axodendritic synapses—are by far the most common type of synapse in the human nervous system.
3. Inhibiting the reuptake of a neurotransmitter will typically cause levels of that neurotransmitter in the synaptic cleft to:
- A. rise
- B. fall
- C. remain stable
Show Answer
Correct answer: A
Neurotransmitter reuptake is a method neurons use to remove excess neurotransmitter molecules from the synaptic cleft. If you were to inhibit reuptake, it would typically cause more neurotransmitter molecules to accumulate in the synaptic cleft (because the neuron would be less capable of removing them). Inhibition of reuptake is the mechanism for a number of psychoactive drugs, including recreational drugs (e.g., cocaine) and therapeutic drugs (e.g., SSRIs).
4. This neuroscientist coined the term "synapse":
- A. Santiago Ramon y Cajal
- B. John Hughlings Jackson
- C. Eric Kandel
- D. Charles Scott Sherrington
Show Answer
Correct answer: D
Sherrington coined the term "synapse." Sherrington had originally planned to use the term syndesm to describe the functional junction between neurons, but a friend suggested synapse, from the Greek meaning "to clasp," since it "yields a better adjectival form."
5. In an electrical synapse, neurons communicate at a specialized region called a:
- A. synaptosome
- B. neurofibril node
- C. gap junction
- D. synaptic hillock
Show Answer
Correct answer: C
Neurons in an electrical synapse communicate through gap junctions, which allow ions to pass directly between cells, enabling rapid, bidirectional signal transmission.
