Final answer:
The two divisions of the superior laryngeal nerve are the internal laryngeal nerve, which provides sensory innervation to the laryngopharynx, and the external laryngeal nerve, which innervates the cricothyroid muscle affecting the vocal cords.
Step-by-step explanation:
The two divisions of the superior laryngeal nerve are the internal laryngeal nerve and the external laryngeal nerve. The internal laryngeal nerve provides sensory innervation to the mucous membrane of the laryngopharynx, which is the region posterior to the larynx.
The laryngopharynx is involved in the respiratory and digestive pathways and continues down where these systems diverge. It is lined with stratified squamous epithelium that is continuous with that of the oropharynx. The external laryngeal nerve, on the other hand, innervates the cricothyroid muscle, which is important in controlling the tension of the vocal cords.
The superior laryngeal nerve itself branches from the vagus nerve and is an essential component in the complex innervation of the larynx. Its divisions play vital roles in voice modulation and protective reflexes within the respiratory system.