The wall of the alimentary canal consists of three layers: outer (connective tissue), middle (muscle tissue), and inner (epithelial tissue). The muscular layer of the oral cavity, pharynx and the upper third of the esophagus consists of striated muscles (a person can regulate the work of these parts of the alimentary canal), and the muscular layer of the underlying parts is represented by smooth muscles.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.