Question

The vagus nerve is composed mainly of parasympathetic fibres.
The preganglionic fibres of the vagus form a network which is known as
A. Choroid plexus
B. Nervous plexus
C. Auerbach’s plexus
D. Brachial plexus

Answer 1

Hint: Vagus is the tenth cranial nerve. It is a mixed nerve, which means it carries both sensory and motor signals. The preganglionic fibres of the vagus nerve form a network that is present in the smooth muscles of the visceral organs.

Complete answer: Auerbach’s plexus, also known as myenteric plexus, provides motor innervations to the muscle layers.
It has both sympathetic and parasympathetic inputs.
It serves as the major nerve supply network to the GI (Gastrointestinal) tract. It also controls the motility of GI tracts by controlling the innervations of smooth muscles that are present in the wall of the stomach, small intestine, etc.

Additional information: The choroid plexus is present in the ventricles of the brain and produces cerebrospinal fluid (CSF). It also helps to secrete CSF.
The Nervous plexus can be defined as the bundle of neurons.
The Brachial plexus is formed with four lower cervical spinal nerves and the first thoracic spinal nerve. It helps to provide nerve supply to the skin and the muscle of arms.
Exception: trapezius muscles and the skin near the axilla do not receive nerve supply from the Brachial plexus; instead they receive nerve supply from the spinal accessory nerve and intercostobrachial nerve respectively.

So, the correct answer is option C. Auerbach’s plexus.

Note: The main difference between Myenteric plexus (Auerbach’s plexus) and Meissner’s plexus is the former has both sympathetic and parasympathetic nerve supply and the later has only parasympathetic nerve supply to the lumen of the gut. The Meissner’s plexus is present in the medulla oblongata.