Mini quiz CH 8,9&10

What type of summation occurs when a postsynaptic neuron receives excitatory postsynaptic potentials (EPSPs) from multiple presynaptic neurons at the same time?

• Temporal summation

• Spatial summation

• Mechanical summation

• Equal summation

What is the neuromuscular junction?

• A synapse between two neurons in the central nervous system.

• The synapse between a sensory neuron and a spinal cord interneuron.

• A synapse between a motor neuron and a skeletal muscle fiber.

• The synapse between a sensory neuron and a skeletal muscle fiber

What best describes the receptors that respond to acetylcholine (ACh) at the neuromuscular junction?

• Voltage-gated sodium channels that open when the membrane potential reaches threshold.

• Ligand-gated ion channels that open when ACh binds to them.

• Mechanically-gated channels that respond to muscle movement.

• Voltage-gated channels that allow direct ion flow between the motor neuron and muscle fiber.

What is the reversal potential for ACh receptors?

• The membrane potential at which the action potential is initiated.

• The resting potential of the muscle fiber before synaptic transmission occurs.

• The voltage at which the Na⁺ channels are fully open and the K⁺ channels are closed.

• The membrane potential at which there is no net movement of charge across the membrane, because the inward and outward ion flows are equal.

What is the quantal hypothesis proposed by Katz?

• The concept that the endplate potential (epp) is the result of simultaneous release of many "quanta" or vesicles containing ACh.

• The idea that each neurotransmitter release produces a single action potential in the postsynaptic neuron.

• The concept that the miniature endplate potential (mepp) is caused by spontaneous voltage gated ion channel opening.

• The theory that ACh is released in large pulses without the involvement of vesicles.

 What is the role of synapsin in synaptic vesicle function?

• Synapsin binds vesicles to actin filaments, anchoring them in place within the axon terminal.

• Synapsin causes vesicle fusion with the presynaptic membrane.

• Synapsin transports neurotransmitter molecules into the vesicles.

• Synapsin promotes the release of neurotransmitters by opening voltage-gated calcium channels.