1. The gastrointestinal tract develops from the endoderm and mesoderm germ layers. Folding of the embryo brings the endoderm inside to form the gut tube with three regions - foregut, midgut and hindgut defined by blood supply.
2. Organ buds form from the endoderm including the liver, pancreas and lungs. The mesoderm layers the gut to form the splanchnic mesoderm.
3. Patterning of the gut is regulated by Hox genes and sonic hedgehog signaling which control regional specification and formation of sphincters.
Development of liver, pancreas, spleen and extrahepatic biliary apparatusSaachiGupta4
Embryology- anatomy
Topic: Development of liver, pancreas, spleen, and extrahepatic biliary apparatus.
For M.B.B.S. students. It gives knowledge on the development of the organs mentioned above and their developmental anomalies
Development of liver, pancreas, spleen and extrahepatic biliary apparatusSaachiGupta4
Embryology- anatomy
Topic: Development of liver, pancreas, spleen, and extrahepatic biliary apparatus.
For M.B.B.S. students. It gives knowledge on the development of the organs mentioned above and their developmental anomalies
posterior abdominal wall is very important structure in abdomen.in this presentation we have to see detailed about posterior abdominal wall muscles .lumbar plexus and nerve supply of posterior abdominal wall .including autonomic sympathetic chain.
In this presentation the development of Small intestine and Pancreas has been discussed. The viewer would be able to understand the concept of physiological herniation and rotation of the Primary intestinal loop with in the connecting stalk.
posterior abdominal wall is very important structure in abdomen.in this presentation we have to see detailed about posterior abdominal wall muscles .lumbar plexus and nerve supply of posterior abdominal wall .including autonomic sympathetic chain.
In this presentation the development of Small intestine and Pancreas has been discussed. The viewer would be able to understand the concept of physiological herniation and rotation of the Primary intestinal loop with in the connecting stalk.
The skin is divided into two parts: the superficial part, the
epidermis; and the deep part, the dermis (Fig. 1.4). The
epidermis is a stratified epithelium whose cells become flat
tened as they mature and rise to the surface. On the palms of
the hands and the soles of the feet, the epidermis is extremely
thick, to withstand the wear and tear that occurs in these
regions. In other areas of the body, for example, on the ante
rior surface of the arm and forearm, it is thin. The dermis is
composed of dense connective tissue containing many blood
vessels, lymphatic vessels, and nerves. It shows considerable
variation in thickness in different parts of the body, tending
to be thinner on the anterior than on the posterior surface.
It is thinner in women than in men. The dermis of the skin
is connected to the underlying deep fascia or bones by the
superficial fascia, otherwise known as subcutaneous tissue.
The skin over joints always folds in the same place, the
SKIN CREASES (Fig. 1.5). At these sites, the skin is thinner
than elsewhere and is firmly tethered to underlying struc
tures by strong bands of fibrous tissue.
The appendages of the skin are the nails, hair follicles,
sebaceous glands, and sweat glands.
The nails are keratinized plates on the dorsal surfaces of
the tips of the fingers and toes. The proximal edge of the
plate is the root of the nail (see Fig. 1.5). With the exception
of the distal edge of the plate, the nail is surrounded and
overlapped by folds of skin known as nail folds. The sur
face of skin covered by the nail is the nail bed (see Fig. 1.5).
Hairs grow out of follicles, which are invaginations
of the epidermis into the dermis (see Fig. 1.4). The folli
cles lie obliquely to the skin surface, and their expanded
extremities, called hair bulbs, penetrate to the deeper part
of the dermis. Each hair bulb is concave at its end, and
05.28.09(a): Development of the Gastrointestinal System Open.Michigan
Slideshow is from the University of Michigan Medical
School's M1 Embryology sequence
View additional course materials on Open.Michigan:
openmi.ch/med-M1Embryology
Development of pancreas from pices to mammals. NizadSultana
Pancreas development in fishes, amphibians, reptiles birds and mammals which factors involve in development of pancreas. Different cells involved in pancreas development.
Similar to Gastrointestinal system embryology (20)
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
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Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
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Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
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2. Gastrulation:
Epiblast cells
migrate through the
primitive streak.
Definitive (embryonic)
endoderm cells displace
the hypoblast.
Mesoderm spreads
between endoderm
and ectoderm.
Langman’s fig 5.3
3.
4.
5.
6.
7. The developing endoderm (yellow) is initially open to the
yolk sac (the cardiac region is initially most anterior)…
Cranio-caudal folding at both ends of the embryo and
lateral folding at the sides of the embryo
bring the endoderm inside and form the gut tube.
Endoderm
Carlson fig 6-20
8. Folding creates the anterior and posterior intestinal portals
(foregut and hindgut, respectively)
The cardiac region is brought to the ventral side of the
developing gut tube.
cloacal membrane
Juxtaposition of ectoderm and endoderm at:
Oropharyngeal (buccopharyngeal) membrane - future mouth
Cloacal membrane - future anus
Note: there actually isn’t much mesoderm in these membranes, which is important for
their breakdown later in development to form the oral and anal orifices.
Carlson fig 6-20
9. Gut-associated organs begin to form as buds from the
endoderm: (e.g., thyroid, lung, liver, pancreas)
Midgut opening to the yolk sac progressively narrows
Carlson fig 6-20
10. By the end of the first month:
The stomach bulge is visible,
Dorsal pancreas has begun to bud
Connection of the midgut to the yolk sac is reduced to
a yolk stalk and then a very thin vitelline duct
Carlson fig 6-20
11. With lateral folding,
mesoderm is recruited to
gut wall
• Lateral folding of the embryo completes the gut tube
• Mesodermal layer of the gut tube is called splanchnic (visceral)
mesoderm - derived from lateral plate mesoderm
• Somatic mesoderm lines body cavity
Langman’s fig 6-18
Carlson fig 6-20
12.
13.
14.
15.
16.
17.
18. Early mesodermal patterning:
(buccopharyngeal membrane)
Specific regions of the epiblast migrate
through the streak at different levels
and assume different positions within
the embryo:
Cranial to caudal:
Notochord (n)
Paraxial mesoderm (pm)
Intermediate mesoderm (im)
*Lateral plate mesoderm (lpm)
Extraembryonic mesoderm (eem)
Langman’s fig 5-07
19. 4th week 5th week
Celiac artery supplies the foregut
Superior mesenteric artery supplies the midgut
Inferior mesenteric artery supplies the hindgut
Langman’s fig 14-14 Langman’s fig 14-4
The figure on the right also shows the mesenteries; note that the liver and stomach have
dorsal and ventral mesenteries whereas the rest of the gut has only a dorsal mesentery.
20. Foregut: pharynx thyroid
esophagus parathyroid glands
stomach tympanic cavity
proximal duodenum trachea, bronchi, lungs
liver, gallbladder
pancreas
Midgut: proximal duodenum to
right half of
transverse
colon
Hindgut: left half of urinary bladder
transverse
colon to anus
Gut tube proper Derivatives of gut tube
(These three regions are defined by their blood supply)
21. Gut = bilayered tube (endoderm surrounded by mesoderm)
Regional gut tube patterning and organogenesis require
bi-directional endoderm-mesoderm cross-talk
and inductive signals from other nearby structures
Regional patterning of the gut tube
22. Regional patterning of the gut tube - the Hox code
Hox genes are evolutionarily
conserved transcription
factors that are used in
regional patterning (flies to
mammals).
The gut has an cranial-caudal
Hox gene expression pattern
(code) similar to that seen in
neural tissue.
Some Hox genes are
expressed in mesoderm, in
overlapping patterns; some
are expressed in endoderm.
Hox gene expression
boundaries correspond to
morphologically recognizable
elements in the GI tract.
Hox gene expression is
important for formation of
major sphincters (red circles) Carlson fig 15-01
23. Hedgehog signaling is important for RADIAL
(concentric) patterning of the entire gut tube
Fetus
• High hedgehog concentration directly inhibits smooth muscle differentiation (via repression of
Smooth Muscle Activating Protein, or Smap)
• Low Hedgehog concentration is permissive of muscle differentiation in the outer wall of the gut
• High Hedgehog concentration also induces high BMP which inhibits neuron formation, thus limiting
neurogenesis initially to the outer muscular wall of the gut (later in development, SHH goes away
allowing development of the smooth muscle of the musularis mucosae and neurons of the
submucosal plexus)
Morphogen: induces different cell fates at different concentrations of signal
Adult Esophagus
Larsen’s fig 14-27
Wheater’s fig 14-5
24. Enteric Nervous System
• Collection of neurons in the GI tract.
• Controls motility, exocrine and endocrine secretion
and microcirculation.
• Regulates immune and inflammatory process.
• Functions independent of CNS.
Image from: Young. Gut 2000
25. Development of Enteric Nervous System
• Primarily derived from the vagal segment of neural crest
cells.
• Cells initially migrate to the cranial section and then
caudally
• Hindgut ganglia receive contributions of cells from the
cranial and sacral segments of the neural crest cells
• Interstitial cells of Cajal arise from the local gut
mesenchyme
Image from: http://www.landesbioscience.com/curie/chapter/2823/
26. Development of the Enteric Nervous System
• Nerve cell bodies are grouped into ganglia
• Ganglia are connected to bundles of nerves forming two plexus
• Myenteric (Auerbach’s)
• Submucosal (Meissner’s)
http://en.wikipedia.org/wiki/Enteric_nervous_system
27. Enteric Nervous System
• Myenteric plexus
• Lies between the circular and longitudinal muscles
• Regulates
• Motility
• Secretomotor function to mucosa
• Connections to
• gallbladder and pancreas
• sympathetic ganglia
• esophageal striated muscle
28. Enteric Nervous System
• Submucosal plexus
• Lies between circular muscle layer and the muscularis mucosa
• Regulates:
• Glandular secretions
• Electrolyte and water transport
• Blood flow
• Similar structure found in gallbladder, cystic duct,
common bile duct and the pancreas
30. Hirschsprung’s Disease
• Congenital disorder
• 1:5000 live births
• Failure of neural crest cells to colonize the entire gut resulting in an
aganglionic zone
• Tonic constriction of aganglionic section
• Long (20%) and Short Segment (80%)
• Short segment 4:1 male:female
• Isolated anomaly in 70% of cases
• Multiple genes and modifier genes identified
• Not mendelian
31. Genetics of Hirschsprung’s Disease
• Associated genes encode members of the glial cell neurotrophic
factor family
• involved in signaling pathways
• transcription factors
• Genes identified
• GDNF
• Ret
• EDNRB
• Sox10
32. Genetics of Hirschsprung’s Disease
• Glial Cell-Derived Neurotrophic Factor (GDNF)
• Member of TGF-β superfamily
• Binds to and activates receptor tyrosine kinase (Ret)
• Defects on GDNF/Ret signaling account for
• 50% familial cases
• 30% of sporadic cases
33. Genetics of Hirschsprung’s Disease
• Endothelin 3 (Et-3) is a secreted protein expressed by gut
mesenchyme.
• Et-3 signals via Endothelin receptor B (Ednrb)
• Ednrb is expressed on migrating enteric neural crest cells
• Mutations in Et-3 and Ednrb account for 5% of cases
34. Genetics of Hirschsprung’s Disease
• Sex determining region Y – box 10 (Sox10) is a high mobility group
transcription factor.
• Expressed on migrating enteric neural crest cells
• Mutations of Sox10 account for 5% of cases
35. Genetics of Hirschsprung’s Disease
• Gene Interactions have been identified in isolated Mennonite
populations and mouse models.
• Ret and Ednrb
• Ret and Et-3
• Sox10 and Et-3/Ednrb
• Mechanisms are unknown –
• ?Downstream signaling
36. Genetics of Hirschsprung’s Disease
• Modifier Genes = Mutated gene that must be coupled with another
mutation to result in or enhance the effect.
• Neuregulin 1 (NRG1) - associates with Ret
• NRG1 signals receptors to regulate neural crest cell development. The receptor is also
associated with Sox10
• Modifiers have also been identified for Sox10 and Et-3 and Ednrb
37. Genes in Gastrointestinal Embryology
• Homeobox-containing transcription factors (Hox genes)
– play a role in gut regionalization
• Sonic Hedgehog (Shh) – transcription factor controls
endodermal-mesenchymal interactions
• Defects associated with TEF and Anorectal malformations
• Possible role in IBD and Malignancy