Small intestine Flashcards
Serve to break big bolus of food into smaller particles
Mixing contraction
Serves to push bolus of food forward or downward to the different segments of the gastrointestinal tract
Propulsive contractions
Contractions cause what in the small intestine?
Segmentation
Prevent the back flow from the colon to the small intestine
Ileocecal valve
What is the maximum frequency segmentation
12 per minute
How many contractions per minute
8-9 contraction/minute in terminal ileum
Segmentation contractions become weak when the excitatory activity of the enteric nervous system is blocked by this drug
Atropine
It propels the chyme and can occur in any part if the small intestine
Peristaltic waves
Peristaltic waves toward the anus at a velocity of ?
0.5 to 2.0 cm/sec
Initiated by distention of the stomach and conducted principally through the myenteric plexus from the stomach down along the wall of the small intestine
Gastroenteric reflex
What enhances intestinal motility
Gastrin
CCK
Insulin
Motilin
Serotonin
What inhibits small intestinal motility
Secretin
Glucagon
It intensifies peristalsis in the ileum and forces the remaining chyme through the ileocecal valve into the cecum of the large intestine
Gastroileal reflex
Intense irritation in the intestinal mucosa as occurs in some severe cases of infectious diarrhea can cause both powerful and rapid peristalsis. Initiate partly by nervous reflexes that involve the ANS and brain stem
Peristaltic rush
It can cause short folds to appear in the intestinal mucosa
Muscularis mucosae
Intensifies contraction to ileocecal sphincter and ileal peristalsis is inhibited
Distention
It delays emptying in the cecum
Irritants
Larger circular movements occur in the large intestine
Mixing Movements (Haustrations)
Has three longitudinal strips
Tarnia coli
A bag like sacs that combines contractions of the circular and longitudinal strips of the muscle
Haustrations
Slow but persistent haustral contractions
Propulsive movements (Mass movements)
A type of modified peristalsis (constructive ring)
Mass movements
A forced mass of feces into the rectum. Weak functional sphincter
Defecation
