Peristalsis

motion of the gastro intestinal tract. movement of the food or bolus from the mouth to the anus. biophysics of smooth muscle contraction in the git.

1. peristalsis Shlok Pushpesh Mathur Nayan Biswas

2. General principles of GIT.. The Gastro intestinal tract helps in the digestion of food with the help of release of digestive enzymes and contraction motion. The Gastro intestinal tract composes of 3 smooth muscle layers which creates a functional syncytium. 2

3. Movement in swallowing.. Deglutition : It is the process of movement of bolous from mouth to the stomach. It has 4 different stages : Oral stage Pharyngeal stage Esophageal stage 3

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5. Movements of the esophagus.. Primary peristaltic contraction Secondary peristaltic contraction 5

6. Primary peristaltic contraction.. When bolus reaches the upper part of the esophagus the peristalsis starts known as the primary peristalsis contraction. After origin the peristalsis passes down through the rest of the esophagus, propelling the bolus towars the stomach. 6

7. Secondary peristaltic contraction.. If the primary peristalsis is unable to take the bolus towards the stomach the secondary peristalsis appears and the bolus moves towards the stomach. 7

8. Contraction in stomach.. Hunger contraction Receptive relaxation Peristalsis 8

9. Hunger contraction.. Movements of empty stomach , related to the sensations of hunger. These are the peristaltic waves superimposed by the cotractions of the gastric smooth muscle as a whole. 9

10. Receptive relaxation .. The relaxation of the uppe rportion of the stomach when bolus enters the stomach from esophagus. 10

11. Peristalsis.. It is a peristaltic wave that appears in the stomach when the bolus passes through the pylorus of the stomach. 11

12. Types of movements in intestine.. Mixing movements.. Segmentation movement Pendular movement Propulsive movement.. Peristaltic movement Peristaltic rush Peristalsis in fasting Movements of villi 12

13. Mixixng movements.. Segmentation contraction: These are the common type of movements of GIT which occurs regularly or irregularly, but in a rhythimic fashion. 13

14. Mixing movements.. Pendular movements.. It is a sweeping movement of the small intestine, resembling the movements of a pendulum of a clock. 14

15. Propulsive movemnts .. Peristaltic movements : It is defined as a wave of contraction followed by a wave of relaxation of muscle fibers. In GIT it always travels in a aboral direction. 15

16. Propulsive movements .. Peristaltic rush : A powerful peristaltic contraction caused by excessive irritation of intestinal mucosa or extreme distension of the intestine. 16

17. Peristalsis in fasting.. Migrating motor complex : It is a type peristaltic contraction which occurs in he stomach and small intestine during the period of fasting for several hours. It is different from regular peristalsis beacause it involves a huge amount of the contracting walls of the stomach or the intestine. 17

18. Moveemnt of the villi.. Intestinal villi also show movements simultaneously, it is because of the extension of the smooth muscle fibers of the intestinal walls into the villi. 18

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