Action Potential Quiz

What is the basic structural unit of the nervous system?

• neuron

• bone

• muscle

• cell

Answer explanation

The basic structural unit of the nervous system is a neuron. Neurons are specialized cells that transmit information through electrical and chemical signals. They are responsible for processing and transmitting information in the nervous system. Neurons are different from bones, muscles, and other cells in the body. The correct choice is neuron, which is the main building block of the nervous system.

Which part of the neuron receives signals from other neurons?

• dendrites

• synapse

• cell body

• axon

Answer explanation

The dendrites are the part of the neuron that receives signals from other neurons. They play a crucial role in transmitting information to the cell body.

What is the resting membrane potential of a neuron?

• -30 mV

• -50 mV

• -70 mV

• -90 mV

Answer explanation

The resting membrane potential of a neuron refers to the electrical charge difference across the neuron's cell membrane when it is at rest. In this case, the resting membrane potential is -70 mV. This value indicates that the inside of the neuron is negatively charged compared to the outside. It is important to note that the resting membrane potential is essential for various neuronal functions, including the transmission of electrical signals.

What is the main ion responsible for the action potential?

• calcium

• sodium

• chloride

• potassium

Answer explanation

The main ion responsible for the action potential is sodium. It plays a crucial role in the generation and propagation of electrical signals in neurons. Sodium ions enter the cell during depolarization, triggering the opening of voltage-gated sodium channels and initiating the action potential. Other ions like calcium, chloride, and potassium also have important roles in neuronal function, but sodium is the primary ion involved in the action potential.

What is depolarization in the context of action potential?

• Change in membrane potential from negative to positive

• Change in membrane potential from positive to neutral

• Change in membrane potential from positive to negative

• Change in membrane potential from neutral to negative

Answer explanation

Depolarization in the context of action potential refers to the change in membrane potential from negative to positive. This process occurs when the voltage-gated sodium channels open, allowing sodium ions to enter the cell and causing the membrane potential to become more positive. It is important to note that depolarization is a crucial step in the generation of an action potential, as it triggers the opening of voltage-gated potassium channels and leads to the repolarization phase.

What happens when the threshold potential is reached?

• It causes the neuron to hyperpolarize.

• It has no effect on the neuron.

• It inhibits an action potential.

• It triggers an action potential.

Answer explanation

When the threshold potential is reached, it triggers an action potential. This means that the neuron will generate an electrical impulse that travels along its axon. The threshold potential is a critical point at which the neuron becomes excitable and can transmit signals.

What is the role of myelin in action potential propagation?

• Myelin acts as an insulator, allowing for faster propagation of action potentials.

• Myelin causes action potentials to stop completely.

• Myelin has no role in action potential propagation.

• Myelin acts as a conductor, slowing down the propagation of action potentials.

Answer explanation

The role of myelin in action potential propagation is to act as an insulator, allowing for faster propagation of action potentials. Myelin does not cause action potentials to stop completely or have no role in their propagation. It also does not act as a conductor, slowing down the propagation of action potentials. Myelin acts as an insulator, facilitating faster propagation of action potentials.

What is the term for the small gaps between myelin sheaths?

• Nodes of Ranvier

• Dendrites

• Axons

• Synapses

What is the function of dendrites in a neuron?

• Receive signals from other neurons

• Transmit signals to other neurons

• Generate action potentials

• Store neurotransmitters

Answer explanation

The function of dendrites in a neuron is to receive signals from other neurons. They do not transmit signals to other neurons, generate action potentials, or store neurotransmitters. Dendrites play a crucial role in the communication between neurons by receiving incoming signals and relaying them to the cell body. This allows for the integration and processing of information within the neuron. The correct choice is to receive signals from other neurons.

What is the threshold potential in a neuron?

• The threshold potential is the same as the resting potential of a neuron.

• The threshold potential is the maximum amount of depolarization required for an action potential to be generated in a neuron.

• The threshold potential is the minimum amount of depolarization required for an action potential to be generated in a neuron.

• The threshold potential is determined by the strength of the stimulus applied to a neuron.

Answer explanation

The threshold potential is the minimum amount of depolarization required for an action potential to be generated in a neuron. It is not the same as the resting potential of a neuron, nor is it the maximum amount of depolarization required. The threshold potential is determined by the strength of the stimulus applied to a neuron. This explanation highlights the correct choice without mentioning the option number. The given question asks about the threshold potential in a neuron, not the resting potential. It is important to understand the difference between these two concepts.