Peristalsis Movements of Alimentary Tract - QS Study
QS Study

Peristalsis Movements of Alimentary Tract

The basic propulsive movement of GIT is peristalsis. Peristalsis is an inherent property of may syncytial smooth muscle tubes. The presence of muscular tissue in the alimentary canal indicates that some sort of movements must be present in the gastrointestinal tract.

Definition

The analward movement of the intestinal contents is called peristalsis. It is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. It occurs in the esophagus, stomach, and intestines.

  • Type: Translatory, to analward
  • Pattern: Proximal contraction and distal relaxation
  • Cause: Distension of gut wall
  • Direction: From mouth to anus.
  • Velocity: 0.5 – 2.0 cm/sec.

Organs in which peristalsis occur: GIT Bile duct ureter.

Fig: Peristalsis Movements

Purpose

(i) To travel the food in a normal direction.

(ii) Helps in a partial mixing of food with digestive Juice.

Mechanism

  • Food in the gut wall
  • Distension of gut
  • (+) Myenteric plexus (gastroenteric reflex)
  • Alternative contraction and relaxation occurs

Contraction moves towards the distended part and thus propelling contents towards iliocaecal valve.

Fig: Peristalsis

Control of peristalsis:

(a) Nervous regulation: Gastroenteric reflex

(b) Hormonal regulation:

  • CCK, Insulin, serotonin → Enhance of movement
  • Secretin, glucagon → Inhibition of movement.

Peristalsis reflex and low of the gut: The complex pattern of peristalsis is not possible without myenteric plexus. This is why it is called peristaltic/myenteric plexus and the analward movement of peristalsis is called a law of the gut.