Synapses Flashcards
What is a synapse?
A specialized site of contact between axon terminals of presynaptic neurons and postsynaptic neurons or effector cells (muscles, glands).
What are the two main types of synapses?
Electrical and Chemical synapses.
How do electrical synapses transmit signals?
Through gap junctions that allow direct current flow between cells
What is the main difference between chemical and electrical synapses?
A: Chemical synapses use neurotransmitters for signal transmission, while electrical synapses transmit current directly.
Q: Define excitatory postsynaptic potential (EPSP).
A: A graded depolarization in the postsynaptic cell that increases the likelihood of an action potential.
Q: Define inhibitory postsynaptic potential (IPSP).
A graded hyperpolarization in the postsynaptic cell that decreases the likelihood of an action potential.
What is synaptic plasticity?
The ability of synaptic transmission to be strengthened or weakened over time, important for learning and memory.
What are the two types of summation that contribute to neural integration?
- Temporal summation
- spatial summation.
What occurs during temporal summation?
Multiple postsynaptic potentials produced by one presynaptic neuron sum if they occur close together in time.
What are ionotropic receptors?
Receptors that open ion channels directly upon neurotransmitter binding, leading to fast responses.
Q: What are metabotropic receptors?
A: Receptors that activate G-proteins and intracellular signaling pathways, leading to slower, longer-lasting effects.
Q: What role do neurotransmitters play at chemical synapses?
A: They are released from presynaptic vesicles and bind to postsynaptic receptors to induce changes in membrane potential.
Q: What is the significance of the synaptic cleft?
A: It is the gap between presynaptic and postsynaptic cells where neurotransmitters diffuse to transmit signals.
Q: What happens when action potentials reach the axon terminal?
A: Voltage-gated Ca²⁺ channels open, allowing calcium influx that triggers neurotransmitter release.
