Final answer:
An effortful swallow encompasses the voluntary, pharyngeal, and esophageal phases of deglutition but does not include the Valsalva's maneuver, which is related to defecation rather than normal swallowing.
Step-by-step explanation:
An effortful swallow includes all phases of deglutition except, typically, the Valsalva's maneuver. Deglutition, or swallowing, is the process of moving food from the mouth to the stomach. This process includes three phases: the voluntary phase, the pharyngeal phase, and the esophageal phase. The Valsalva's maneuver is not a part of normal swallowing; rather, it is an action that involves a voluntary contraction of the diaphragm and the abdominal wall muscles and closing of the glottis to increase intra-abdominal pressure, which is primarily associated with defecation.
During the voluntary phase, the individual initiates swallowing by pushing the bolus to the back of the oral cavity with the tongue. Muscles also work to keep the mouth closed to prevent food from falling out. Once the bolus enters the oropharynx, the involuntary pharyngeal phase begins, involving reflex actions controlled by the deglutition center in the medulla oblongata to ensure food does not enter the respiratory pathways. In the esophageal phase, peristalsis moves the bolus through the esophagus toward the stomach, while mucus from esophageal glands lubricates the passageway.