The synapse’s effectiveness in transmitting nerve impulses is most critically determined by which of the following?

Correct option is C

The correct answer is (c) The concentration of neurotransmitter and the number of receptors in the postsynaptic membrane

Explanation:

• The synapse's effectiveness in transmitting nerve impulses is most critically determined by two factors: the concentration of neurotransmitters released into the synaptic cleft and the number of receptors on the postsynaptic membrane.
• When a nerve impulse reaches the presynaptic neuron, it triggers the release of neurotransmitters (chemical messengers). These neurotransmitters then bind to specific receptors on the postsynaptic membrane, generating a response in the next neuron.
• The strength and efficiency of this synaptic transmission depend on how many receptors are present and how much neurotransmitter is available to bind to those receptors.

Information Booster:

• A high concentration of neurotransmitters can lead to stronger or more prolonged stimulation of the postsynaptic neuron.
• The density of receptors on the postsynaptic membrane influences the neuron's sensitivity to the neurotransmitter.
• This mechanism is key to synaptic plasticity, a process involved in learning and memory, where synaptic strength is modified based on the frequency and intensity of neurotransmitter release.

Additional Knowledge:

(a) The diameter of the axon

• While the diameter of the axon influences the speed of nerve impulse transmission (thicker axons conduct impulses faster), it is not the primary determinant of synapse effectiveness.

(b) The length of the dendritic arborisation

• The length of the dendritic arborisation affects the number of synaptic inputs a neuron can receive, but it does not directly impact synapse transmission efficiency.

(d) The presence of myelin sheaths along the dendrites

• Myelin sheaths help in the fast conduction of action potentials along axons, but dendrites typically do not have myelin sheaths, and myelination does not directly affect the synapse's effectiveness in neurotransmission.