Nerve

Repolarisation of an activated neuron does NOT include:

• Opening of voltage-gated Na⁺ channels

• Opening of voltage-gated K⁺ channels

• Shifting membrane potential towards resting levels

• Inactivation of voltage-gated Na⁺ channels

Tags

NGSS.HS-PS3-5

What is a motor unit?

• A muscle fibre and all the neurons it innervates

• A motor neuron and all the muscle fibres that it innervates

• All the nerve fibres and muscle fibres contained in one fascicle

• A motor neuron and a single muscle fibre that it innervates

True or False?

At threshold (-60mV), voltage-gated K⁺ channels are closed and voltage-gated Na⁺ channels open.

• True

• False

Local Potentials

• Depolarise the membrane to the same level (+30 mV) each time

• Depolarise or hyperpolarise the membrane to different levels

• Propagate down the axon

• Associate with voltage-gated ion channels

The region of the neuron where all local potentials summate is the

• Dendrite

• Cell body

• Axon hillock

• Axon Terminal

True or False?

A neurotransmitter from a pre-synaptic neuron binds to a voltage-gated ion channel on the dendrite of a post-synaptic neuron

• True

• False

What is labeled #6?

• Axon

• Neurotransmitter

• Synapse

• Calcium Channel

When an action potential reaches a neuromuscular junction, which of the following will happen first?

• Acetylcholine binds to acetylcholinesterase and depolarizes the cell.

• Sodium ion gates and potassium ion gates open at the same time.

• Acetylcholine enters into the synapse to bond with receptor proteins.

• Vesicles containing acetylcholine fuse with the presynaptic membrane.

What is labeled #1

• Synapse

• Neurotransmitter

• Synaptic Vesicle

• Motor End Plate

What is labeled #2?

• Synaptic Vesicles

• Calcium Channel

• Motor End Plate

• Synapse