Which of the following is NOT a function of dendrites?
A. Convey incoming messages toward the cell body
B. Generate nerve impulses and transmit them away from the cell body
C. Provide enormous surface area for receiving signals from other neurons
D. Produce short-distance signals called graded potentials
The Correct Answer and Explanation is :
The correct answer is B. Generate nerve impulses and transmit them away from the cell body.
Explanation:
Dendrites are extensions of a neuron that primarily serve the purpose of receiving signals from other neurons. They play several crucial roles in neuronal communication, but generating and transmitting nerve impulses is not one of them.
Function A: Convey incoming messages toward the cell body – Dendrites are responsible for receiving signals, usually in the form of neurotransmitters, from the synaptic terminals of other neurons. They convey these incoming signals toward the neuron’s cell body, which integrates the information.
Function C: Provide enormous surface area for receiving signals from other neurons – Dendrites have a branched structure that increases their surface area. This anatomical feature allows a single neuron to form numerous synapses with other neurons, facilitating complex communication networks in the brain.
Function D: Produce short-distance signals called graded potentials – When dendrites receive signals, they generate graded potentials. These potentials are local changes in membrane potential that vary in magnitude and are proportional to the strength of the incoming signal. If these graded potentials reach a certain threshold at the axon hillock (the junction between the cell body and the axon), they can trigger an action potential, which is the nerve impulse that travels away from the cell body.
In contrast, Function B describes a role of the axon, not the dendrites. The axon is the part of the neuron that carries the nerve impulse away from the cell body to other neurons, muscles, or glands. While dendrites are critical for receiving and processing incoming signals, they do not generate action potentials; that function is exclusive to the axon. Therefore, the generation and transmission of nerve impulses away from the cell body is not a function of dendrites, making option B the correct choice.