Karteikarten
macrh 16th
Karten in diesem Stapel (86)
- 1Occlusion of lumen5-6 weeks.
Recanalization of gut lumen: 7-8 weeks. - 2Normal recannalization of gut tubeUnder normal circumstances, small vacuoles form as the gut tube expands. These cavities fuse together until the gut eventually forms a tube with a single lumen.
- 3Abnormal recannalization of gut tube.In some cases, one point will have too few vacules in it, and in one or two locations can develop only a narrow lumen (a stenosis; e.g., pyloric stenosis).
On rare occasion, one spot may not have any such vacuoles and consequently no lumen will form in that spot, creating an atresia. Example, pyloric atresia (which can be in one limited spot or over a broad area - 4Oropharyngeal platebecomes part of mouth
- 5Omphaloenteric (Vitelline) Ductyolk sac connects to gut tube through this
- 6symptoms associated with stenosis of foregutEsophageal atresia
Pyloric stenosis
Duodenal stenosis/atresia - 7Esophageal atresiaresults in immediate spit-up of first meal; not terribly violent but accompanied by lots of coughing; no bile present
- 8Pyloric stenosisAfter a while, manifests in projectile vomiting of feedings; no bile present.
- 9Duodenal stenosis/atresiaAfter meal is over, find vomiting (not excessively violent) with bile present; usually in 3rd or 4th part of duodenum, so bile duct is proximal to stenosis.
- 10Gastric rotationliver moves to left and spleen moves to right and keep doing this until the gut tube rotates clockewise 90
- 11Adult mesenteries derived from the ventral mesogastriuimTriangular ligament of the liver
Falciform ligament
Lesser Omentum - 12Adult derivatives of the dorsal mesogastriumGastrosplenic ligament
Gastrocolic lig.
Greater omentum - 13Pancreatic developmentThree original buds, two associated with liver/gallbladder and the third more dorsal, both sets on opposite sides of the duodenum from each other.
The duodenum rotates as the stomach and small intestines do; the buds rotate until they are adjacent and ultimately fuse. One ventral bud disappears.
The pancreas functions as both exocrine (digestive) and endocrine (glucose regulatory) organ. - 14The pancreatic ventral bud and bile duct rotate first to the right then behind the duodenum; these pancreatic buds fuse into one pancreas; ventral = head and adjacent areas, dorsal = body & tail.Left ventral pancreatic bud degenerates; head and uncinate process derive only from right ventral pancreatic bud, while dorsal bud gives rise to neck, body and tail.
- 15Initial rotation of gut inside of herniationit continues to rotate so that it will eventually be at 180°, still in the umbilical herniation.
- 16at 10 weeks the gut is at 180 it thenreneters the abdominal cavity and completes rotationg to make a full 270
- 17After retraction and rotation are complete the duodenum,ascending colon and descending colon become retroperitoneal by fusion to the peritoneum of the posterior body wall.
- 18..
- 19..
- 20Mucosain the alimentary canal it is as follows. While it may be a little modified in other organs they will still have similar layers.
Of primary importance in gut, for digestion, absorption, and protection of deeper layers. - 21mucosa hasEpithelium
Tubular Mucosal glands
Lamina propria (loose connective tissue)
Muscularis mucosae. - 22..
- 23Omphaloenteric (Vitelline) ductExists at 5th to early 6th week as a connection between the secondary umbilical vesicle (yolk sac) and the midgut.
The ‘secondary umbilical vesicle’ detaches after 6 weeks, so the omphaloenteric (vitelline) duct typically disappears.
Occasionally, remnants of the duct persist and remain in contact by one means or another to the umbilicus. - 24Persistence of Omphalo-enteric (Vitelline) duct.Types of persistence of O-E duct (a defect):
Ileal (Meckel’s) diverticulum, with or without fibrous connection to umbilicus.
O-E cyst, with fibrous connections to ileum and/or umbilicus.
Ileoumbilical fistula. - 25Rotations of the mesenteries and formation of the greater omentum as well as fusions intoretroperitoneal space.
- 26..
- 27Abnormal rotation of the gut variationsReversal of rotation, with or without situs inversus.
Absence of rotation of the gut.
Abnormal twists of the gut (volvulus), which occurs because of return to abdominal cavity.
Omphalocoele. - 28Absence of rotation.Small intestine coils up on right side of abdomen.
Large intestine folds up on left side of abdomen. - 29Reversal of RotationDuodenum anterior to transverse colon.
that means super messentary artery goes over transverse colon which will cause buildup if feces on right side - 30Volvulus; twisted gutIf the developing colon twists around on itself during development, it causes a ‘kink,’ or volvulus.
- 31Anorectal anomalies occur at about 1 in 4000 live births, and includeAnal stenosis.
Imperforate anus (anal atresia).
Rectovaginal (female) or rectourethral (male) fistula.
Rectal atresia. - 32Mucosal EpitheliumVaries from one location to another;
Esophagus it is stratified squamous nonkeratinizing, in small and large intestines it is simple columnar epithelium.
The epithelium also includes the simple tubular glands - 33Mucosal Lamina PropriaUnder epithelium, between glands; contains few fibers but lots of immuno-competent cells. Notice lots of plasma cells. Also fibroblasts, macrophages.
- 34Muscularis mucosae.This is literally the “muscle of the mucosa.”
It is the final barrier before the rest of the layers.
Consists of a thin layer containing a few layers of smooth muscle cells. - 35Submucosa.Contains blood vessels and nerves, including a set of nerve ganglia (submucosal plexus, or Meissner’s plexus). Sparsely populated with nerve cells.
- 36Muscularis externaTwo to three very thick layers of smooth muscle for peristaltic movement. Usually circular and longitudinal.
inner and outer layer - 37Inner layertypically circular and wraps around the gut in a tight spiral
Between layers is a large nerve plexus, the myenteric (Auerbach’s) plexus. - 38The outer layeris longitudinal, and it can sometimes be a bit thinner than the circular layer.
- 39Serosa/adventitiaOutermost layer of the alimentary canal.
- 40Serosain abdominal cavity) comprises the visceral peritoneum and closely associated CT. Occurs in intraperitoneal organs.
- 41Adventitiaoccurs in extraperitoneal (generally retroperitoneal) organs, and comprises the connective tissue that connects gut to the body wall.
- 42Glands in the alimentary canalUnicellular glands
Simple mucosal glands - 43Unicellular glandsGoblet cells. Found in the epithelium.
- 44Simple mucosal glandsglands Various forms of basically simple or branched tubular glands. Scattered.
- 45Autonomic nervesMyenteric (Auerbach’s) plexus is large, located between circular and longitudinal muscle.
Submucosal (Meissner’s) plexus is small, located inside of submucosa. - 46Myenteric plexus is located betweenbetween circular and longitudinal layers of smooth muscle. It is large and conspicuous, providing most input, both to muscular layer and mucosa.
- 47Submucosal plexus is locatedscattered in submucosa, and is smaller, associated with vessels of submucosa.
- 48the enteric system influneced byInfluenced but not controlled by sympathetic and parasympathetic inputs.
These comprise a ‘nerve net brain,’ which has central control at major junctions, e.g., gastroesophageal junction, pyloric end of duodenum, iliocolic junction - 49Arterioles make it up villi, break up into capillaries where nutrients are absorbed, and then pass back down in veinules, ending up in portal veins.increase the effincey of nutrients
- 50The lactealis an enlarged origin of a lymphatic capillary.
Lymph flows down and receives other local lymph capillaries
They then get together to form larger ducts, then to nodes, then to thoracic duct. - 51Peyer’s Patchesare in ileum, solitary nodules are elsewhere.
- 52Because of the nature of the gut it WILL have associated bacteria. The immune system is strong in this organ..
- 53Surface area of small intestine is in increased byFolding of small gut increases its overall length, and therefore surface area.
Circular folds (“Valves of Kerkrung”) are folds inside the gut, made up of mucosa with a core of submucosa.
Villi. Projections of epithelium into the lumen with a core of lamina propria.
Microvilli. Microscopic projections from the apical surface of the epithelial cells that increase their overall surface area. - 54Esophagusbegins at C6
occupies superior and posterior mediastina as it descends towards abdomen.
Passes through esophageal hiatus of diaphragm (at approx. T10 level).
Joins stomach immediately thereafter - 55esophagus made ofHas skeletal muscle in upper 1/3, mixed skeletal and smooth in middle 1/3, and only smooth muscle in lowest 1/3.
Skeletal muscle in upper and middle portions of muscularis externa. - 56type of epithtlim of esophagStratified squamous nonkeratinizing epithelium.
- 57Esophageal hiatus of diaphragm (note leaflets)allows passage of food into diaphram
- 58StomachThe stomach can expand as food comes in; gastcic secretion doubles the total volume in the stomach.
- 59Entry to the stomach is permitted through thegastroesophageal sphincter, which typically is supposed to restrict its backflow.
- 60Exit from the stomach is via thepyloric sphincter to the duodenum.
- 61Stomach general histologyGastric epithelium, simple columnar mucous cells.
Gastric pits lined with surface epi.-open up to Branched tubular glands - 62stomach Three muscular layers:Innermost oblique (mixing)
Inner circular (peristalsis)
Outer longitudinal. (peristalsis) - 63Gland neckWhere new gland cells come from
(stem cells)
provides cells that go up and down - 64Cells of the gastric glandNeck
base - 65neckmucous cells and stem cells (note, stem cells form all new cells for stomach, both gland and surface). Occasional parietal cells.
- 66baseChief cells: secrete protein (pepsinogen)
Parietal cells: secrete HCl, intrinsic factor. - 67Mucous neck cellhas mucous granules
- 68Parietal cellhas intracellular canuliculus, numerous mitochondria
- 69Chief cells-zymogen granules (pepsinogen).
- 70VillusLine entire small intestine (only this organ has this)
- 71Villus cell typesEpithelium
Lamina propria - 72Epitheliumconsists of columnar cells (enterocytes) and goblet cells, with occasional APUD cells.
- 73Lamina propriaconsists of lots of IgA-producing plasma cells, macrophages, lymphocytes, fibroblasts and occasional eosinophils with smooth muscle connecting the villus to the muscularis mucosae.
- 74Lamina PropriaIt has lymphocytes, macrophages, fibroblasts, plasma cells, a lymph duct (lacteal) and smooth muscle.
- 75LactealThe center of the villus contains the beginning of a lymphatic duct.
- 76Intestinal crypts (glands of of Lieberkuhn) locatedNear the base of the glands are stem cells that produce all the cells for the small intestinal epithelium.
At the crypt base are Paneth cells which are antibacterial (secrete Lysozyme, can phagocytose bacteria).
Glands also secrete fluids & a small amount of mucus. - 77Submucosal (Brunner’s) glandsin duodenum
ONLY in first part. Produce alkaline mucus, secrete on cholinergic stimulation. Counteract gastric acidity. - 78Jejunum hasextremely tall plicae circulares found in
- 79Ileum hasPeyers patches--collections of lymphoid nodules-- are most common in Ileum, though occasionally found in jejunum.
- 80Peyer’s patchesLymphoid accumulations 1° found in ileum.
Primarily produce IgA, which is secreted into lumen via enterocytes.
has M cells - 81M-cellssample intact antigens and present these antigens to lymphocytes. Can transfer entire bacteria. Occasionally exploited by pathogenic bacteria, prions.
- 82Large intestineshas no villi and sirface is flat
Has large population of bacteria, particularly anaerobic bacteria. - 83Colon general histo.Flat epithelium--no villi
Deep crypts with numerous mucous cells.
Band of longitudinal muscle (tenia coli) - 84Stem cells in large intestineStem cells in crypt base (note, the large gut does NOT have Paneth cells).
They migrate upwards as they differentiate.
They wind up in the surface; they slough off like small intestinal cells when they die. - 85Mucosa of large intestineFlat surface
Deep crypts with numerous mucous cells. - 86Colon mucosaMany host defense cells to help protect against invading bacteria: macrophages, lymphocytes, plasma cells, etc.
Stem cells at crypt base. Immature columnar cells have some mucous granules (‘vacuolated’ cells).
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- Karteikarten am macrh 16th, erstellt von Shylla T am 05/04/2020.
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