Movements in small and large intestine

1. Movements In Small & Large Intestine
Dr. Sara Sadiq
(MBBS, M.Phil)

2. 2
Small Intestine
• Long tube  about 6m
• Extending from pyloric sphincter in
stomach and joins large intestine at the
ileocecal sphincter
• Duodenum, jejunum and ileum.
• Surface area greatly increased by intestinal
mucosal foldings  villi and microvilli.

3. 3Function
• Digestion  Disaccharidases and aminopeptidases.
• Absorption  large surface area.
(Site where most digestion and absorption take place).
• Secretion
• Motility

4. 4Intestinal motility
• Function of Intestinal Motility are:
1. To mix chyme with digestive secretion
2. To bring fresh chyme into contact with the absorptive surface of the microvili
3. To propel chyme toward the colon
• Types:
1. Segmental
2. Peristaltic

5. 1. Segmental Movement
Ring-like contractions. Mix chyme and expose it to absorptive surface.

7. 2. Peristalsis
A wave of contraction preceded by relaxation. Propels the
gastrointestinal contents toward the large intestine.

8. http://medweb.bham.ac.uk/research/toescu/Teaching/OverviewGITY2.html

10. 10
Movement in Small Intestine
Peristalsis (ou propulsivos) e Segmentation (mixing)
http://medweb.bham.ac.uk/research/toescu/Teaching/OverviewGITY2.html

11. Control of Peristalsis of Small Intestine
1. Nervous Factors
2. Hormonal Factors

12. 1. Nervous Factors
1. Entry of meal in duodenum
• Stretch
2. Gastroenteric reflex
• Distension of stomach
• Myenteric plexus
3. Movements of Muscularis Mucosa and Contraction of villi are
controlled by submucosal plexus

13. 2. Hormonal Factors
↑ motility
• Gastrin
• CCK
• Insulin
• Motilin
• Serotonin
↓ motility
• Secretin
• Glucagon

14. Peristaltic Rush
• Rapid and powerful peristalsis that travel long distance in small
intestine within minutes  sweeping intestinal contents into colon.
• Initiated by myenteric plexus & ANS
• Caused by  intestinal irritation e.g. diarrhea

15. Migrating Motor Complex (MMC)
• Peristaltic wave sweep slowly and
rhythemically in stomach and small
intestine once every 1-2 hrs during fasting
state
• Helps in sweeping excess digestive
secretions into colon and preventing their
accumulation in upper GIT.

16. 16Large intestine
• No digestive function.
• Absorption of water, Na+ and other minerals.
• Secretion of mucus for lubrication.
• Storage of feces (undigested food).

17. 17

18. Large intestinal motility patterns

19. Segmentation in large intestine
Haustration:
Modified form of segmentation in which intense,
local contraction of circular and longitudinal
muscle causes bulging of unstimulated portion
of large intestine

20. Large intestinal motility patterns
2. Mass movement:
• Period of intense propulsive activity that moves entire contents of colon
distally toward rectum
• Contractions progress for long distance such that long length of colon
contracts as a unit
• Entry of fecal matter into rectum triggers defecation reflex
• A mass movement is a modified type of peristalsis

21. Large intestinal motility patterns
Stimulant for Mass movement:
• Gastrocolic reflex
• Duodenocolic reflex
• Extrinsic nervous system
• Irritation in colon (Ulcerative colitis)

22. Thank You…