Postganglionic sympathetic axons are known as:Nicotinic fibresCholinergic fibresBeta blockersAdrenergic fibres

Postganglionic sympathetic axons are known as Adrenergic fibres.

Here's a step-by-step explanation:

1. The autonomic nervous system is divided into the sympathetic and parasympathetic systems.

2. The sympathetic nervous system is responsible for the body's 'fight or flight' response. It is activated in response to stress and danger.

3. The sympathetic nervous system is composed of preganglionic and postganglionic neurons.

4. Preganglionic neurons release acetylcholine, a neurotransmitter that activates nicotinic receptors on the postganglionic neurons.

5. Postganglionic neurons in the sympathetic nervous system, in turn, release norepinephrine (also known as noradrenaline), a neurotransmitter that activates adrenergic receptors on the target organs.

6. Therefore, postganglionic sympathetic axons are referred to as adrenergic fibres because they release norepinephrine and activate adrenergic receptors.

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