Question 21

The axon carries action potential in the direction of a synapse.

The axon is the structure of the nervous system responsible for transmitting action potentials away from the cell body and toward the synapse, facilitating communication between neurons.

A) cell body

The cell body, or soma, contains the nucleus and organelles of the neuron but does not propagate action potentials. Instead, it is the site where electrical signals are integrated before they are transmitted down the axon.

B) axon

The axon is specifically designed to carry action potentials away from the neuron’s cell body towards the synapse. It is the elongated part of the neuron that conducts electrical impulses, making it the correct answer.

C) neuron

While the neuron as a whole can transmit action potentials, it is not a specific structure that carries them in a directed manner. The term "neuron" encompasses various components, including the cell body, dendrites, and axon, but it is the axon that is responsible for the directionality of action potentials.

D) myelin

Myelin is a lipid-rich substance that insulates the axon and increases the speed of action potentials as they travel along the axon. However, myelin itself does not carry action potentials; it merely enhances the efficiency of their transmission.

Conclusion

The axon is the definitive structure that carries action potentials toward synapses, making it the correct answer. The other options either do not transmit action potentials (cell body), refer to the entire neuron without specifying the directional component (neuron), or describe a supportive feature that does not conduct impulses (myelin). Understanding this distinction is essential in the study of neuronal communication.