Question

Which statement about an action potential is true? 1. It "skips" over segments of myelin, hopping from one node of Ranvier to the next. 2. It is a neurotransmitter that relays messages from motor neurons to muscles, enabling movement.3. It defends the brain from infection and inflammation.4. It has a nucleus containing DNA.

Answer 1

1. It "skips" over segments of myelin, hopping from one node of Ranvier to the next.

Step-by-step explanation:

The action potential is the electrical signal. It is produced in neurons and muscle cells to propagate the nerve impulse. It is fired when the membrane of a neuron is depolarized. Myelinated axons exhibit saltatory conduction of action potential. This means that the action potential is propagated from one node of Ranvier to the next while skipping the in-between myelinated region. This occurs since the voltage-gated channels are mainly concentrated at the nodes of Ranvier. Therefore, the action potential is mainly carried at nodes where Na+ and K+ flow across the membrane.