It includes the parts of small intestine and large intestine. Includes its layers, mucosa, submucosa, muscularis and serosa. discussed also is duodenum, jejunum and ileum. and Cecum, ascending colon, descending colon , transverse colon, descending colon and sigmoid colon. Also includes its functions, sphincters and blood and nerve supply

1. ANATOMY OF
SMALL AND LARGE INTESTINE
BY : MS SAILIGAUDE
PRINCIPAL SHIVAM COLLEGEOF NURSING

2. SMALL INTESTINE
 Small intestine is section of digestive tract
where the majority of food digestion and
nutrient absorption take place
 Small intestine is an organ located in the
gastrointestinal tract, between the stomach
and large intestine
 Small intestine made up by three parts, the
duodenum, the jejunum and the ileum.

3. PARTS OF SMALL INTESTINE
 DUODENUM
 Duodenum is the first section of intestine that connects to the pyloric sphincter of
the stomach.
 It is shortest region of the small intestine, measuring only about 10 inches in
length.
 Partially digested food or chyme, from stomach is mixed with bile from the liver
and pancreatic juice from pancreas to complete its digestion in the duodenum.

4.  JEJUNUM
 Jejunum is the middle section of the small intestine that serves as the primary site
of nutrient absorption. It measures around 3 feet in length.
 ILIUM
 Ileum is the final section of the small intestine that empties into the large
intestine via the ileocecal sphincter
 Ileum is about 6 feet long and completes the absorption of the nutrients that were
missed in the jejunum

5. STRUCTURE OF SMALL INTESTINE
 Made up of 4 layers
 1) Mucosa – forms the layer of epithelial tissue and is specialized for the
absorption of nutrients from chyme
 2) Submucosa – deeper to the mucosa. Contains blood vessels, lymphatic vessels
and nerves to support the mucosa on the surface
 3) Smooth muscles- several layers of smooth muscles contracts and moves the
small intestine
 4) Adventitia or serosa forms the outermost layer of epithelial tissue that is
continuous with the mesentry and surrounds the intestines. Comprised of loosely
arranged fibroblasts and collagen, with the vessels and nerves passing through it

7. OTHER FEATURES
 1. circular folds are the transverse folds of mucosa found predominantly in the
distal duodenum and proximal jejunum
 Intestinal villi are fingerlike extensions of intestinal mucosa which project into the
small intestine. Between the villi are intestinal glands which secretes intestinal
juice rich in enzymes.
 Microvilli are projections found on surface of each intestinal cells called as
enterocytes

9. LARGE INTESTINE
 Also called colon
 Is part of final stages of digestion
 Large tube that escorts waste from the body
 Colon is 6ft long
 Lies just inferior to the stomach and wraps around the superior and lateral border
of the small intestine
 Large intestine absorbs water and contains many symbiotic bacteria that aid in
the breaking down of wastes to extract some small amounts of nutrients
 Feces from the large intestine exit through the anal canal

11. STRUCTURE OF LARGE INTESTINE
 4 LAYERS
 1) MUCOSA
 2) SUBMUCOSA
 3) MUSCULARIS LAYER
 4) SEROSA

12. 1) MUCOSA
 Innermost layer
 Made up of simple columnar epithelial tissue
 Smooth
 Lacks villi
 Many mucous glands secretes mucus into the hollow lumen of the large intestine
to lubricate its surface and protect it from rough food particles

13. 2) SUBMUCOSA
 Surrounding the mucosa is a layer of blood vessels, nerves and connective tissue
known as submucosa
 Supports the other layers of the large intestine

14. MUSCULARIS LAYER
 Surrounds the submucosa and contains many layers of visceral muscle cells that
contract and move the large intestine.
 Made up of 2 muscles – inner circular muscle and outer longitudinal muscle.
 Continous contraction of smooth muscle bands in the muscularis produces lumpy,
pouch like structures known as haustra in the large intestine

15. SEROSA
 Serosa forms the outermost layer of the large intestine or colon
 The serosa is thin layer of simple squamous epithelial tissue that secretes watery
serous fluid to lubricate the surface of the large intestine, protecting it from
friction between abdominal organs and the surrounding muscles and bones of the
lower torso.

16. PART OFTHE LARGE INTESTINE
 1. CECUM
 2. ASCENDING COLON
 3.TRANSVERSE COLON
 4. DESCENDING COLON
 5. SIGMOID COLON

17. CECUM
 It is a pouch like structure
 Receives undigested food material from the small intestine and is considered the first
region of the large intestine.
 Separated from the ileum by the ileocecal valve
 This valve limits rate of food passage into the cecum and may help prevent material from
returning to the small intestine
 Cecum is first section of the colon
 It is not involved in digestion
 Appendix develops embryologically from it
 Function – absorb fluids and salts that remain after completion of intestinal digestion
 Absorption and to mix mucus to lubricate the end product

19. ASCENDING COLON
 Ascending colon runs upwards through the abdominal
cavity towards the transverse colon for approx. 20 cm
 When it meets the right lobe of the liver it takes a 90
degree turn to move horizontally
 This turn is known as the right colic flexure or hepatic
flexure
 It marks the start of transverse colon

20. TRANSVERSE COLON
 Part of the colon from the hepatic flexure also
known as the right colic to the splenic flexure
also known as the left colic
 The splenic flexure is the place where the
transverse colon meets the spleen on the left
side and than take a 90 degree turn to move
downward in vertical direction
 Transverse colon hangs off the stomach ,
attached to it by a large fold of peritoneum
called greater omentum

21. DESCENDING COLON
 Part of the colon from the splenic flexure ro the beginning of the sigmoid colon
 Main function – store feces that will be emptied into the rectum

22. SIGMOID COLON
 Part of large intestine
 Placed after descending colon
 Just before the rectum
 Sigmoid colon is ‘S’ shaped organ of large
intestine
 Walls of the sigmoid colon are muscular
and contract to increase the pressure
inside the colon, causing the stool to
move into the rectum.

23. BLOOD SUPPLY
 ARTERIAL SUPPLY- colon comes from branches of the superior mesenteric artery
and inferior mesenteric artery
 VENOUS DRAINAGE- usually mirrors colonic arterial supply with inferior
mesenteric vein draining into the splenic vein and the superior mesenteric vein
joining the splenic vein to form the hepatic portal vein that the enter the liver