Biological Systems MCAT Practice Exam

How does the structure of a bipolar neuron differ from other neurons?

1. It has two axons

2. It has one axon and one dendrite

3. It is unipolar

4. It has more than two dendrites

The correct answer is: It has one axon and one dendrite

The structure of a bipolar neuron is characterized by having one axon and one dendrite, which is distinctive compared to other neuronal types. This structural arrangement allows bipolar neurons to effectively transmit signals between multiple types of neurons and is commonly located in specific sensory pathways, such as those involved in vision and smell. In particular, bipolar neurons play a critical role in sensory systems, where the single dendrite receives input from sensory receptors and the single axon transmits impulses to the next neurons in the pathway. This simple structure aids in the efficient processing of sensory information. Other neuron types exhibit different structures: unipolar neurons have a single process that branches into a dendrite and an axon, while multipolar neurons possess one axon and multiple dendrites, allowing for integration of a larger number of synaptic inputs. The unique structural feature of bipolar neurons thus supports their specialized functions within the nervous system.