Question

a sensory signal traveling from the thumb to the cns will pass a few checkpoints. which of the following lists the order of the checkpoints passed? a) dorsal root, spinal nerve, dorsal ramus, brachial plexus, receptor b) receptor, ventral ramus, spinal nerve, brachial plexus, ventral root c) receptor, brachial plexus, ventral ramus, spinal nerve, dorsal root d) dorsal root, ventral root, dorsal ramus, brachial plexus, receptor

Explanation:

Sensory signals start at the receptor. The brachial plexus is a network of nerves that the signal from the thumb (upper limb) would pass through. The ventral ramus is part of the spinal nerve distribution. The spinal nerve is a mixed nerve (but here we focus on sensory). The dorsal root is where sensory neurons enter the CNS. Options a and d start with dorsal root (wrong as signals start at receptor). Option b has incorrect sequence with ventral root (motor related mostly, and sequence is off).

Answer:

C. Receptor, brachial plexus, ventral ramus, spinal nerve, dorsal root