Question

Describe the muscular composition of the esophagus and its effects on deglutition

A) A. The esophagus has smooth muscle and skeletal muscle, aiding in both voluntary and involuntary stages of deglutition.
B) A. The esophagus is composed solely of smooth muscle, facilitating involuntary swallowing during deglutition.
C) A. The esophagus has skeletal muscle, allowing for voluntary control during deglutition.
D) A. The esophagus contains cardiac muscle, ensuring a rhythmic contraction during deglutition.

Answer 1

The esophagus consists of both skeletal and smooth muscles, aiding in voluntary and involuntary phases of deglutition. Skeletal muscle is found in the upper part, while the lower part is composed of smooth muscle, facilitating peristalsis and entry of the food into the stomach.

Step-by-step explanation:

The muscular composition of the esophagus includes both smooth muscle and skeletal muscle. The upper two-thirds of the esophagus mainly consist of skeletal muscle, which permits voluntary control during the initial stage of deglutition or swallowing. As food progresses downward, the muscle composition transitions to smooth muscle in the lower third of the esophagus, which facilitates the involuntary phase of peristalsis, propelling food toward the stomach.

During deglutition, the medulla oblongata controls the complex neuromuscular actions involved, initiating peristalsis to move the food bolus through the esophagus. The rhythmic contractions of the circular and longitudinal muscle layers of the esophagus are crucial for pushing the bolus forward and for the relaxation of the lower esophageal sphincter, allowing food to enter the stomach.