[Comparative evaluation of the muscular coat of the esophagus from fish and mammals].

Light optic analysis revealed that morphological parameters of fish and mammals oesophageal parameters are conditioned functionally. Combination of respiratory and transport functions in anterior portion of digestive systems in fish determines insignificant length of the esophagus and developed muscular coat which excludes disorders of gas exchange. Heterodonteal dentition, pulmonary type of respiration and long esophagus of mammals provide factors that unable to prevent gas exchange. Electron microscopic study of oesophageal fibres of these animals demonstrated that they are alike in their structure with skeletal muscular fibres.