The statement that is NOT true about axons is:
- Whereas dendrites typically are myelinated, axons seldom are myelinated.
Explanation:
1. Axons are typically longer than dendrites. This statement is true. Axons are the elongated part of a nerve cell that conducts electrical impulses away from the cell body, and they can be much longer than dendrites.
2. Axons contain sodium, potassium, and calcium ion gates in their membranes. This statement is true. Axons have ion channels in their membranes that help in the transmission of electrical signals by regulating the flow of ions such as sodium, potassium, and calcium.
3. Axons seldom are myelinated. This statement is not true. In reality, many axons are myelinated, which means they are covered by a fatty substance called myelin. Myelination helps speed up the conduction of nerve impulses along the axon.
4. Axons terminate in synaptic knobs containing vesicles. This statement is true. Axon terminals end in structures called synaptic knobs or boutons, which contain vesicles filled with neurotransmitters. These neurotransmitters are released into the synapse to communicate with other neurons or target cells.
