Intestines(movements and secretions of small and large intestines) Distended Portion of small intestine with chyme stretching  concentric contractions at intervals  lasting a fraction of a minute These contraction causes “Segmentation” of the small intestine ---forms spaced segments  new points every time  chopping chyme 2-3 times/min  mixing with intestinal secretions  maximum frequencyof segmentation contraction depends on frequency of BER (Basic electrical rhythm) i.e. In duodenum and proximal jejunum is 12/min and in terminal ileum is 8-9/min. Atropine blocks the segmentation law of gut The peristaltic reflex +anal direction of movement of the peristalsis is called “LAW OF GUT”

1. Source: The Guyton and Hall physiology
Maryam Fida (o-1827)

2. Functional types of movements
Propulsive
movements
(peristalsis)
Mixing
movements

3. Mixing contractions (Segmentation Contractions)
• Distended Portion of small intestine with chyme stretching  concentric
contractions at intervals  lasting a fraction of a minute These contraction
causes “Segmentation” of the small intestine ---forms spaced segments 
new points every time  chopping chyme 2-3 times/min  mixing with
intestinal secretions  maximum frequencyof segmentation contraction
depends on frequency of BER (Basic electrical rhythm) i.e. In duodenum and
proximal jejunum is 12/min and in terminal ileum is 8-9/min.
• Atropine blocks the segmentation

4. Mixing movement

5. Mixing contraction of the Small Intestine.
Rhythmic Segmentations Bring Through
Mixing of the Intestinal Content

6. Law of GUT
• The peristaltic reflex +anal direction of movement of
the peristalsis is called “LAW OF GUT”

7. PROPULSIVE MOVEMENTS
1. Peristalsis in the small intestine
2. Peristaltic Rush

8. 1. Peristalsis
• Chyme is propelled through the small
intestine by “ PERISTALTIC WAVES”
• Start in any part of small intestine at
0.5-2 cm/sec towards anus
• They are usually weak
• Die after 3-5 cm not > than 10 cm
• Very slow
• Thus, net movement along the small
intestine averages only 1 cm / min
• 3-5 hrs for passage of chyme from
pylorus  illeocecal valve
Functions:
1. Progression of chyme towards
iliocecal valve
2. Spread chyme along intestinal
mucosa
 Gastro enteric reflex:
initiation of intestinal
peristalsis foods in stomach
 Gastroileal reflex :
intensification of peristalsis in
illium and to presence of 2nd
meal in stomach  forces
remaining food through the
illiocecal valve into the
caecum

9. Peristalsis
stretch
vagal
irritants
Contractile rings
++Enteric neurons

12. Nervous signals = Gastroenteric reflex
Hormonal :
1. Stimulatory: gastrin , cck ,insulin , motillin &
serotonin
2. Inhibitory: secretin, glucagon
Factors affecting small intestinal peristalsis:

13. Peristaltic Rush
Mostly peristalsis in the small intestine is weak but
sometimes , powerful peristaltic contraction occurs is
called “PERISTALTIC RUSH “
CAUSE
1. Intense irritation of intestinal mucosa
2. Infectious diarrhea
Tanveer Raza MD MS MBBS
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14. Iliocecal valve
• Prevents backflow of fecal matter
from colon into small intestine
• Illeocecal sphincter: remained
mildly constricted  slows emptying
of illeal content into cecum
• Gastroileal reflex: intensification of
illeal peristalsis 2nd to 2nd meal 3-4
hrs after the 1st one ,by which chyme
is forcefully pushed through
illeocecal valve into the caecum
• Functions of illiocecal valve
Prevention of back flow of fecal
content from colon by:
1. Protrusion of illeocecal valve
into the caecum  remain
forcefully closed in pressure &
Can resist 50-60cm of H2O
reverse pressure
2. Iliocecal sphincter:
 Terminal illeal circular muscular
constriction
 Remain mildly closed
 Slow emptying

16. SECRETIONS OF THE SMALL INTESTINE

17. SECRETION OF THE SMALL INTESTINE
• Secretion of mucus by Brunner’s Glands in the duodenum
• Secretion of intestinal Digestive juices by the Crypts of
Lieberkuhn
Tanveer Raza MD MS MBBS
razajju2@yahoo.com

18. Secretion of Mucous by
Brunner’s Gland in the
Duodenum
LOCATION: Brunner’s Glands is
located in the wall of the first few
centimeters of the duodenum,
mainly between the pylorus of the
stomach and the papilla of vater,
where pancreatic secretion and
bile empty in to the duodenum.
SECRETION: These glands secrete
large amount of alkaline mucous.
STIMULI: 1. Tactile or irritating
stimuli
• 2. Vagal stimuli 3. Secretin
FUNCTION:1. To protect the
duodenum wall from digestion by
the acidic gastric juices emptying
from the stomach.
2. Neutralizing the HCL entering the
duodenum from the stomach
INHIBITED BY SYMPATHETIC STIMULI
Tanveer Raza MD MS MBBS
razajju2@yahoo.com

19. SECRETION BY THE
CRYPTS OF LIEBERKUHN
LOCATION: Found all over the
small intestine
CELLS: 1. GOBLET CELL which
secrete mucous that lubricates
and protect
2. ENTEROCYTES Secrete water
and electrolytes such as
chloride and bicarbonate and
digestive enzymes
DIGESTIVE ENZYMES.
1. Peptidases: for splitting small
peptides in to aminoacids
2. Four enzymes- sucrose, maltase,
isomaltase and lactase for
spiltting diasaccharides yin to
monosaccharides
3. Intestinal lipase for spiltting
neutral fats in to glycerol and
fatty acids
Tanveer Raza MD MS MBBS
razajju2@yahoo.com

20. Large Intestine

21. Basic Function are:
1. Absorption of water & electrolytes from chyme by
proximal half
2. Storage of fecal matter by distal half
So sluggish movements required
MOVEMENTS OF COLON

22. 1. Mixing Movements or “ HAUSTRATIONS”
2. PROPULSIVE MOVEMENTS or “ MaSS MOVEMENTS”
Movements of the Colon

23. MIXING MOVEMENTS”HAUSTRATIONS
• Like mixing movements in
small intestine, large circular
constrictions occur in large
intestine.
• 2.5 cm circular muscle
constriction to occlusion
• Tinea coli contraction( Three
longitudinal strips)
• These combine contraction
of circular and longitudinal
strips of muscle cause the
unstimulated portion of large
intestine to bulge outward in
to bag like sacs called “
Haustrations”
• Haustration reaches to its paek in
30 sec and repeat in 60 sec
• After another few min new
haustration appears
• Fecal matter dug into & rolled
over in large intestine
• In 8-15 hrs from illeocecal valve
 through colon
• 80-200 milliliter/day semisolid
fecal mater is formed

24. PROPULSIVE MOVEMENTS (MASS MOVEMENT
Mass movements:
1. Mass movement propels the feces
from colon towards the anus.
2. From cecum to sigmoid
3. These movements occurs only 1-3
times each day.
4. Mostly about 15 min during 1st
hour after breakfast
Sequence of events:
1. constrictive ring occurs in response to
distention & irritation in transverse colon
2. 20 cm distal to it loose haustration &
contract as a unit
3. En mass propelling of fecal contents
4. Contraction for 30 sec, relaxation in next 2-
3 min
5. Series of such movements persist for 30
min ,then cease and return half day later

Feces reach rectum  desire of defecation

25. STIMUALANT OF MASS MOVEMENT
• 1.Gastrocolic reflex
• 2. Duodenocolic reflex
• These reflexes result from
distension of the stomach
and duodenum
• 3. Irritation in the colon
• 4. Ulcerative Colitis
• Ulcerative colitis:
ulcerated portion of colonic
mucosa , leads to intense
mass movement
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26. Secretions of Large Intestine
• Have only crypts of Lieberkuhn.
• No villi
• No digestive enzymes
• Only secrete Mucus

27. Secretions of Large Intestine
• Mucus provides protection
• Parasympathetic stimulation increases rate of goblet cell secretion
• Bacterial actions produce gases (flatus) from particular kinds of
carbohydrates found in legumes and in artificial sugars like
sorbitol
• Bacteria produce vitamin K which is then absorbed
• Feces consists of water, undigested food (cellulose),
microorganisms, sloughed-off epithelial cells