Gastrointestinal Tract - Intestine Development

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midgut herniation

The part of the gastrointestinal tract (GIT) lying between the stomach and anus, is described as the intestines or bowel. This region is further divided anatomically and functionally into the small intestine or bowel (duodenum, jejunum and ileum) and large intestine or bowel (cecum and colon). Initially development concerns the midgut region, connected to the yolk sac, and the hindgut region, ending at the cloacal membrane. This is followed by two mechanical processes of elongation and rotation. Elongation, growth in length, leaves the midgut "herniated" at the umbilicus and external to the abdomen. Rotation, around a mesentery axis, establishes the anatomical position of the large intestine within the peritoneal space.

Migration of neural crest cells into the wall establishes the enteric nervous system, which has a role in peristalsis and secretion. Prenatally, secretions also accumulate in this region and are the first postnatal bowel movement, the meconium.

The small intestine grows in length rapidly in the last trimester, at birth it is about half the eventual adult length (More? Small Intestine Length). Like most of the gut, this region is not "functional" until after birth, when development continues by populating the large intestine with commensal bacteria and the establishment of the immune structure in the wall.

GIT Links: Introduction | Medicine Lecture | Science Lecture | Endoderm | Mouth | Stomach | Liver | Gall Bladder | Pancreas | Intestine | Tongue | Taste | Enteric Nervous System | Stage 13 | Stage 22 | Abnormalities | Movies | Postnatal | Milk | Tooth | Tongue | BGD Lecture | BGD Practical | GIT Terms | Category:Gastrointestinal Tract
GIT Histology Links: Upper GIT | Salivary Gland | Smooth Muscle Histology | Liver | Gall Bladder | Pancreas | Colon | Histology Stains | Histology | GIT Development
Historic Embryology
1878 Alimentary Canal | 1882 The Organs of the Inner Germ-Layer The Alimentary Tube with its Appended Organs | 1902 The Organs of Digestion | 1906 Liver | 1907 Development of the Digestive System | 1907 Atlas | 1907 23 Somite Embryo | 1908 Liver and Vascular | 1912 Digestive Tract | 1917 Entodermal Canal | 1918 Anatomy | 1921 Alimentary Tube | 2016 GIT Notes | Historic Disclaimer
Human Embryo: 1908 13-14 Somite Embryo | 1926 22 Somite Embryo | 1907 23 Somite Embryo | 1937 25 Somite Embryo | 1914 27 Somite Embryo | 1914 Week 7 Embryo
Animal Development: 1913 Chicken | 1951 Frog
Historic Embryology: 1912 Small Intestine | 1912 large Intestine

Some Recent Findings

Model for cloacal septation[1]
  • Review - How to make an intestine[2] With the high prevalence of gastrointestinal disorders, there is great interest in establishing in vitro models of human intestinal disease and in developing drug-screening platforms that more accurately represent the complex physiology of the intestine. We will review how recent advances in developmental and stem cell biology have made it possible to generate complex, three-dimensional, human intestinal tissues in vitro through directed differentiation of human pluripotent stem cells.
  • Bmp7 functions via a polarity mechanism to promote cloacal septation[1] "During normal development in human and other placental mammals, the embryonic cloacal cavity separates along the axial longitudinal plane to give rise to the urethral system, ventrally, and the rectum, dorsally. Defects in cloacal development are very common and present clinically as a rectourethral fistula in about 1 in 5,000 live human births. Yet, the cellular mechanisms of cloacal septation remain poorly understood. ...Our results strongly indicate that Bmp7/JNK signaling regulates remodeling of the cloacal endoderm resulting in a topological separation of the urinary and digestive systems. Our study points to the importance of Bmp and JNK signaling in cloacal development and rectourethral malformations."
  • Fgf9 signaling regulates small intestinal elongation and mesenchymal development [3] "Short bowel syndrome is an acquired condition in which the length of the small intestine is insufficient to perform its normal absorptive function. ...These data suggest a model in which epithelial-derived Fgf9 stimulates intestinal mesenchymal stem cells (iMSCs) that in turn regulate underlying mesenchymal fibroblast proliferation and differentiation at least in part through inhibition of Tgfbeta signaling in the mesenchyme."
More recent papers
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This table shows an automated computer PubMed search using the listed sub-heading term.

  • Therefore the list of references do not reflect any editorial selection of material based on content or relevance.
  • References appear in this list based upon the date of the actual page viewing.

References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

Links: References | Discussion Page | Pubmed Most Recent | Journal Searches

Search term: Intestine Embryology

Ufuk Ates, Gulnur Gollu, Gonul Kucuk, Deniz Billur, Meltem Bingol-Kologlu, Yavuz Yılmaz, Hulya Ozkan-Ulu, Pinar Bayram, Emin Bagriacik, Huseyin Dindar Increase in pro-apoptotic Bax expression and decrease in anti-apoptotic Bcl-2 expression in newborns with necrotizing enterocolitis. [Incremento de la expresión de Bax (proapoptótico) y disminución de la expresión de Bcl-2 (antiapoptótico) en recién nacidos con enterocolitis necrosante.] Arch Argent Pediatr: 2016, 114(3);243-247 PubMed 27164337

Michaela Vrabcova, Livia Mikuska, Rastislav Vazan, Michal Miko, Ivan Varga, Boris Mravec Effect of chronic intake of liquid nutrition on stomach and duodenum morphology. Acta Histochem.: 2016; PubMed 27131951

U Eren, S Kum, A Nazligul, O Gules, E Aka, S Zorlu, M Yildiz The several elements of intestinal innate immune system at the beginning of the life of broiler chicks. Microsc. Res. Tech.: 2016; PubMed 27115541

Masaki Ogata, Tsunetoshi Itoh Gamma/delta intraepithelial lymphocytes in the mouse small intestine. Anat Sci Int: 2016; PubMed 27056578

K Karaman, M Ercan, H Demir, M Yener Uzunoglu, S Bostanci Acute intestinal obstruction due to a non-involuted uterus after cesarean section: case report. Clin Exp Obstet Gynecol: 2016, 43(1);146-8 PubMed 27048040

Adult Intestine

Adult jejunum histology

Intestinal Regions

Small intestine or bowel length (see also Fetal Intestine Length and Small Intestine Length)

  • Duodenum (adult 25 cm length)
  • Jejunum (adult 1.4 m length)
  • Ileum (adult 3.5 m length)

Large intestine or bowel

  • Cecum (caecum)
    • Vermiform appendix ("appendix", adult 2 to 20 cm length)
  • Colon
    • Ascending colon (adult 25 cm length)
    • Transverse colon
    • Descending colon
    • Sigmoid colon

Intestinal Functions

Small Intestine

  • absorption of nutrients and minerals found in food
  • Duodenum -principal site for iron absorption


  • connects the ileum with the ascending colon
  • separated by the ileocecal valve (ICV, Bauhin's valve)
  • connected to the vermiform appendix ("appendix")


  • absorbs fluid, water and salts, from solid wastes
  • site of commensal bacteria (flora) fermentation of unabsorbed material

Embryonic Development

Week 4

Quicktime | Flash

Week 8

Quicktime | Flash

Stage 22 image 088.jpg Stage 22 image 089.jpg

Late embryonic small intestine commencing at the duodenum, continuing as ventrally herniated and returning to join the colon.

Links: Carnegie stage 22 | Week 8


Normal intestinal rotation cartoon.jpg

Normal intestinal rotation[4]

Fetal Intestine Length

Fetal small Intestine length growth graph.jpg Fetal large Intestine length growth graph.jpg
Fetal small Intestine length growth Fetal Large Intestine length growth

Data from [5][6]

Small Intestine Length

Small intestine growth in length is initially linear (first half pregnancy to 32 cm CRL), followed by rapid growth in the last 15 weeks doubling the overall length. Growth continues postnatally but after 1 year slows again to a linear increase to adulthood.[7]

Age (weeks gestational age) Average Length (cm)
20 125
30 200
term 275
1 year postnatal 380
5 years 450
10 years 500
20 years 575

Table data based upon 8 published reports of necropsy measurement of 1010 guts.[7]


Anatomically the distal third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon and rectum. The developmental timing of the anus and rectum formation[8] in human embryos of the Carnegie Collection has been previously carried out (1974). A more recent study[9] has also been made of the Kyoto Collection embryos.

There has been some recent controversy over the "anal membrane" formation.

A recent study hindgut and anorectum development in human embryos shows that Wnt5a is active in this region prior to anus formation, when it is down-regulated.[10]

Other studies - PMID 19496155 PMID 10504783 PMID 9562679 PMID 9243909 PMID 21708335 (rat)

Intestinal Motility

The enteric nervous system neural crest-derived neurons interacts with the circular and longitudinal smooth muscle layers and the interstitial cells of Cajal to generate motility. The developmental timing data shown below is from a recent review.[11]

Neural Crest

week 5 - migrating neural crest cells reach the midgut

week 7 - neural crest cells have colonized the entire gut

  • colonization occurs in a rostro-caudal sequence

Myenteric plexus (Auerbach's plexus, named after Leopold Auerbach (1828–1897) a German anatomist and neuropathologist.)

  • is first formed plexus
  • lies between the outer longitudinal and inner circular layers of muscularis externa
  • provides motor innervation to both layers
  • secretomotor innervation to the mucosa
  • has both parasympathetic and sympathetic input

Submucosal Plexus (Meissner's plexus, named after Georg Meissner (1829–1905) a German anatomist and physiologist.)

  • forms 2-3 days after the myenteric plexus
  • formed by cells migrating from the myenteric plexus
  • innervates smooth muscle of the muscularis mucosae
  • has only parasympathetic fibers

Smooth Muscle

week 8 - esophagus circular muscle

week 11 - hindgut circular muscle

week 14 - hindgut concentric muscularis mucosae, circular muscle, and longitudinal muscle

Interstitial Cells of Cajal

Interstitial cells of Cajal (ICC) are electrical pacemaker cells within the gastrointestinal tract smooth muscle. They create the basal (slow waves) rhythm required for contraction and peristalsis. They are mesodermal in origin.

weeks 7-9 - cells initially appear

week 11 - distinct clusters

week 12-14 - clustered around myenteric ganglia along the entire gut

Links: Neural Crest Development


Abnormality Links: Gastrointestinal Tract - Abnormalities | Intestine Development | Gastrointestinal Tract

Cite this page: Hill, M.A. (2016) Embryology Gastrointestinal Tract - Intestine Development. Retrieved May 26, 2016, from

What Links Here?
© Dr Mark Hill 2016, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
Links: Gastrointestinal Tract - Abnormalities | Image - Small intestine duplication

Appendix Duplication

Appendix duplication is an extremely rare congenital anomaly (0.004% to 0.009% of appendectomy specimens) first classified according to their anatomic location by Cave in 1936[12] and a later modified by Wallbridge in 1963[13], subsequently two more types of appendix abnormalities have been identified.[14][15]

Modified Cave-Wallbridge Classification (table from[16])

Classification of types
of appendix duplication
A Single cecum with various degrees of incomplete duplication
B1 (bird type) Two appendixes symmetrically placed on either side of the ileocecal valve
B2 (tenia coli type) ne appendix arises from the cecum at the usual site, and the second

appendix branches from the cecum along the lines of the tenia at various distances from the first

B3 One appendix arises from the usual site, and the second appendix arises from

the hepatic flexura

B4 One appendix arises from the usual site, and the second appendix arises from

the splenic flexura

C Double cecum, each with an appendix
Horseshoe appendix One appendix has two openings into a common cecum
Triple appendix One appendix arises from the cecum at the usual site, and two additional appendixes arise from the colon

Short Bowel Syndrome

Short bowel syndrome (SBS) results typically due to developmental abnormalities, extensive intestinal resection during the neonatal period, or necrotising enterolitis.[17]

  • reduces gut function for digestion and absorption of nutrients (intestinal failure).

Links: PubMed Health | Better Health

Molecular Factors

  • Cdx (Caudal-type homeobox) group of ParaHox genes (mouse Cdx1, Cdx2 and Cdx4)[18]
  • FGF9


  1. 1.0 1.1 Kun Xu, Xinyu Wu, Ellen Shapiro, Honging Huang, Lixia Zhang, Duane Hickling, Yan Deng, Peng Lee, Juan Li, Herbert Lepor, Irina Grishina Bmp7 functions via a polarity mechanism to promote cloacal septation. PLoS ONE: 2012, 7(1);e29372 PubMed 22253716
  2. James M Wells, Jason R Spence How to make an intestine. Development: 2014, 141(4);752-60 PubMed 24496613 | Development
  3. Michael J Geske, Xiuqin Zhang, Khushbu K Patel, David M Ornitz, Thaddeus S Stappenbeck Fgf9 signaling regulates small intestinal elongation and mesenchymal development. Development: 2008, 135(17);2959-68 PubMed 18653563
  4. Vicki Martin, Charles Shaw-Smith Review of genetic factors in intestinal malrotation. Pediatr. Surg. Int.: 2010, 26(8);769-81 PubMed 20549505 | PMC2908440
  5. J FitzSimmons, A Chinn, T H Shepard Normal length of the human fetal gastrointestinal tract. Pediatr Pathol: 1988, 8(6);633-41 PubMed 3244599
  6. John G Archie, Julianne S Collins, Robert Roger Lebel Quantitative standards for fetal and neonatal autopsy. Am. J. Clin. Pathol.: 2006, 126(2);256-65 PubMed 16891202
  7. 7.0 7.1 L T Weaver, S Austin, T J Cole Small intestinal length: a factor essential for gut adaptation. Gut: 1991, 32(11);1321-3 PubMed 1752463 | PMC1379160 | Gut.
  8. de Vries PA. and Friedland GW. The staged sequential development of the anus and rectum in human embryos and fetuses. (1974) J. Pediatr. Sure., 9(5): 755-69 PMID 4424274
  9. Ryozo Hashimoto Development of the human tail bud and splanchnic mesenchyme. Congenit Anom (Kyoto): 2013, 53(1);27-33 PubMed 23480355
  10. Fei Fei Li, Tao Zhang, Yu Zuo Bai, Zheng Wei Yuan, Wei Lin Wang Spatiotemporal expression of Wnt5a during the development of the hindgut and anorectum in human embryos. Int J Colorectal Dis: 2011, 26(8);983-8 PubMed 21431850
  11. Alan J Burns, Rachael R Roberts, Joel C Bornstein, Heather M Young Development of the enteric nervous system and its role in intestinal motility during fetal and early postnatal stages. Semin. Pediatr. Surg.: 2009, 18(4);196-205 PubMed 19782301
  12. A J Cave Appendix Vermiformis Duplex. J. Anat.: 1936, 70(Pt 2);283-92 PubMed 17104589
  13. P H WALLBRIDGE Double appendix. Br J Surg: 1962, 50;346-7 PubMed 13998581
  14. T W Mesko, R Lugo, T Breitholtz Horseshoe anomaly of the appendix: a previously undescribed entity. Surgery: 1989, 106(3);563-6 PubMed 2772830
  15. L F Tinckler Triple appendix vermiformis--a unique case. Br J Surg: 1968, 55(1);79-81 PubMed 5635427
  16. Emel Canbay, Emel Akman Appendix perforation in appendix duplication in a man: a case report. J Med Case Rep: 2011, 5;162 PubMed 21513538 | J Medical Case Reports | PDF
  17. G Davì, A Pinto, M G Palumbo, V Gallo, A Mazza, A Strano Dipyridamole and aspirin in arteriosclerosis obliterans of the lower limbs. Adv. Prostaglandin Thromboxane Leukot. Res.: 1985, 13;271-5 PubMed 3159212
  18. Felix Beck, Emma J Stringer The role of Cdx genes in the gut and in axial development. Biochem. Soc. Trans.: 2010, 38(2);353-7 PubMed 20298182


James M Wells, Jason R Spence How to make an intestine. Development: 2014, 141(4);752-60 PubMed 24496613

Taeko K Noah, Bridgitte Donahue, Noah F Shroyer Intestinal development and differentiation. Exp. Cell Res.: 2011, 317(19);2702-10 PubMed 21978911

Alan J Burns, Rachael R Roberts, Joel C Bornstein, Heather M Young Development of the enteric nervous system and its role in intestinal motility during fetal and early postnatal stages. Semin. Pediatr. Surg.: 2009, 18(4);196-205 PubMed 19782301


Jelly Hm Soffers, Jill Pjm Hikspoors, Hayelom K Mekonen, S Eleonore Koehler, Wouter H Lamers The growth pattern of the human intestine and its mesentery. BMC Dev. Biol.: 2015, 15(1);31 PubMed 26297675

Yui Ueda, Shigehito Yamada, Chigako Uwabe, Katsumi Kose, Tetsuya Takakuwa Intestinal rotation and physiological umbilical herniation during the embryonic period. Anat Rec (Hoboken): 2015; PubMed 26599074

Tae-Hee Kim, Byeong-Moo Kim, Junhao Mao, Sheldon Rowan, Ramesh A Shivdasani Endodermal Hedgehog signals modulate Notch pathway activity in the developing digestive tract mesenchyme. Development: 2011, 138(15);3225-33 PubMed 21750033

Won Kyu Kim, Hyun Kim, Dae Ho Ahn, Myoung Hee Kim, Hyoung Woo Park Timetable for intestinal rotation in staged human embryos and fetuses. Birth Defects Res. Part A Clin. Mol. Teratol.: 2003, 67(11);941-5 PubMed 14745932

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Cite this page: Hill, M.A. (2016) Embryology Gastrointestinal Tract - Intestine Development. Retrieved May 26, 2016, from

What Links Here?
© Dr Mark Hill 2016, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G