Which of the following statements is INCORRECT? The esophagus produces digestive enzymes. The esophageal mucosa consists of nonkeratinized stratified squamous epithelium. At each end of the esophagus, the muscularis forms two sphincters the upper esophageal sphincter and the lower esophageal sphincter. The upper esophageal sphincter consists of skeletal muscle and the lower of smooth muscle. The esophagus secretes mucus and transports food to the stomach.