Question

question 22
which of the following is the correct reflex arc pathway from pns toward the spinal cord?
a receptor, afferent neuron, dorsal root
b receptor, efferent neuron, dorsal root
c receptor, efferent neurons, ventral root
d effector, afferent neuron, ventral root

Explanation:

• Receptor: Detects the stimulus.
• Afferent neuron (sensory neuron): Transmits the sensory information from the receptor to the central nervous system (spinal cord in this case).
• Dorsal root: Carries sensory (afferent) information into the spinal cord.
• Efferent neurons (motor neurons) carry information away from the central nervous system to effectors (like muscles or glands), so options B and C are incorrect as they mention efferent neurons for the pathway towards the spinal cord.
• Option D is incorrect because it starts with an effector (which is the target of the motor response, not the initiator of the sensory - to - spinal - cord pathway) and also has the wrong root (ventral root is for motor/efferent output).

Answer:

A. receptor, afferent neuron, dorsal root