Question

Membrane Potential

1. The resting membrane potential of a neuron is _________.   The membrane potential changes when _________. A change in membrane potential to a more positive value is called __________ and a change to a more negative value is called _______.
2. Ions flow through _________ which are controlled by voltage and ________ which are controlled by _________.
3. Neurons communicate with other neurons and targets by generating _________. Ghe neuron generates an action potential only if it reaches a threshold voltage of _________. The phases of an action potentials are _________ which is caused by entry of sodium ions, _________ which is caused by _________, and hyperpolarization which is caused by ________.
4. Once generated, action potentials propagate towards the __________. Along the way, the size of the action potential (decreases/stays the same).
5. Neurons also generate __________ which are short-lived. These signals are necessary for bringing the neuron to its ___________

Events at the Synapse

1. The arrival of action potential at axon terminal triggers _________ which triggers the release of _______ which binds to __________ on the postsynaptic neuron. Ions will enter the postsynaptic neuron to generate local potentails called ________. These local potentials will __________ to generate another _________.

Neurotransmitters

1. The most common excitatory neurotransmitter in the brain is __________; and the most excitatory neurotransmitter in the spinal cord is ________. GABA generates ___________ in the _______ and glycine generates _________ in the _______. Other common neurotransmitters are _________ which is involved in mood disorders; _______ which is released by the parasympathetic nervous system; ________ which is released by the sympathetic nervous system.

Answer 1

1. The resting membrane potential of a neuron is about -70 mV.

Justification: It is the electrical potential energy and the inside of a cell membrane is more negative than outside.

2. The membrane potential changes when signals are generated by opening or closing of ion channels in the membrane.

Justification: Changes in membrane potential occurs when the signals are generated by an opening or closing of ion channels at any point in the membrane and this change is affected by the ion channels in the membrane.

3. A change in membrane potential to a more positive value is called depolarization and a change to a more negative value is called hyperpolarization.

Justification: During the depolarization phase, the internal negative charge of cell becomes more positive and this shift from the negative to the more positive potential includes an action potential. During hyperpolarization, the positive charge becomes more negative. Hyperpolarization is opposite to depolarization.

4. Ions flow through channels which are controlled by voltage and chemical (concentration) gradients.

5. Neurons communicate with other neurons and targets by generating action potentials and chemical neurotransmitters.

Justification: Neurons communicate with each other and targets by generating action potentials and chemical neurotransmitters.

6. The neuron generates an action potential only if it reaches a threshold voltage of -55 mV.

Justification: If a neuron reaches a threshold voltage of -55 mV, it generates an action potential.

Thank you!