1 In-text citations in parenthesis, with only the author's last name and page number included (Smith, p. 4). 2  Double-spaced lines, but with no extra line breaks between each citation. 3  Footnotes (superscripted) also used to provide non-essential information.
Muscularis Extema is the layer of the digestive tract wall that is responsible for peristalsis.
Peristalsis in the Digestive System. Peristaltic waves are produced by contractions of smooth muscles. One set of smooth muscles contract behind the chewed food to keep it from moving back into the mouth. Another set of smooth muscles then pushes the food forward along the digestive tract.