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92 Cards in this Set
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GI tract 4 layers |
MUCOSA (lumen side) SUBMUCOSA MUSCULARIS EXTERNA SEROSA or ADVENTITIA |
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Mucosa |
3 layers Epithelium lamina propria (thin layer of CT) muscularis mucosa (1-2 layers of SM) |
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2 layers of muscularis externa |
inner: circular outer: longitudinal |
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serosa vs adventitia for outside layer (dense CT) |
serous membrane=visceral peritoneum adventitia=retroperitoneal parts |
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UES |
upper esophageal sphincter skeletal muscle involved in deglutition reflex (swallow) contr'd by CN 9, 10, 12 normally closed, only relaxes (opens) for bolus main fxn: prevent backflow of food from esoph to pharynx involved in eructation (burping) |
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trigger peristalsis in esoph |
bolus present--->stretch pharynx tactile receptors from pharynx to esophagus: pharyngeal peristalsis down esophagus: esophageal |
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LES |
gastroesophageal sphincter (lower esoph) Smooth muscle prevent reflux of gastric contents into esoph normally, relaxes (opens) when bolus reaches gastroesoph jxn |
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two most common clinical problems with LES |
Achalasia GERD |
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Achalasia |
failure to relax LES cant open LES! (stays closed) food accum in esoph cant empty into stomach common sx: regurgitation (into mouth) dysphagia (trouble swallowing) inflamm confirm? x ray: esophagram (pic with barium probed food so lit up all accumulated in bottom of esophagus, shows food stuck there not emptying) dilated proximal esophagus and narrow tapering of distal esophagus=birds beak sign |
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GERD |
Gastro-esoph reflux disease occurs if LES is incompetent=stays open (wont close!) acidic contents of stomach back into distal esoph---->esoph damage=barrets esoph most common sx: heartburn, substernal chest pain (nausea, regurg, dysphag, etc.) most common diagnostic: endoscopy: esophagoggastroduodenoscopy (EGD) |
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stomach |
j shaped sack left upper quadrant under diaphragm HCl, chemical digestion begins in stomach. bolus turn to chyme internal surface lined with simple columnar epithelium with goblet cells small invaginations of epithel into mucosa=gastric pits or foveolae two borders of stomach (curvatures): medial border=lesser curvature (lil concave side facing medially) lateral border-greater curvature (convex side facing lat left side of abdominal cav) |
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when stomach is empty the mucosa of internal surface of stomach make |
rugae: rough irregular longitudinal folds rugae permit expansion of stomach as it fills |
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4 parts of stomach |
cardia: part closest to esoph (part right from when esophagus and LES meet beginning of stomach=cardia) lil beginning of stomach section
(that top bump) body: biggest middle part pylorus: last bottom part before connection to duodenum (further divided into antrum and canal) |
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pylorus |
(after body of stomach is over the pylorus is last part of stomach before duodenum) divided into pyloric antrum, where stomach turns to the right like bottom part start curving medially (which is to the right cuz we are on the left) pyloric canal, where stomach becomes narrower, end of stomach part right before duod pyloric canal ends with pyloric sphincter aka gastroduodenal sphincter (separate stomach from duod) |
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parietal cells |
of stomach aka oxyntic cells produce HCl produce IF (essential for b12 absorpt) |
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cheif cells |
of stomach produce pepsinogen (zymogen converted to pepsin in presence of HCl) |
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Pepsin |
breaks down peptide bonds in proteins |
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when stomach contents processed into chyme and pass thru pyloric sphincter into duodenum |
brunners glands of duod secrete alkaline secretion to neutralize the chyme |
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pylorospasm |
failure of pyloric sphinter to relax (cant open) (food cant pass from stomach to duod) usually transient, imperfect neuromuscular regulation of pyloric sphincter more common in kids than adults -->congenital pyloric stenosis |
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congenital pyloric stenosis |
abnormal dvlpmnt of pyloric sphincter permanent! doesnt allow for passage of food at all usual presentation: non bilious projectile vomiting w/in first week of life requires surgical repair |
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gastritis |
inflammation of stomach mucosa two types of chronic gastritis: type a, type b can lead to peptic ulcer |
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type a gastritis |
autoimmune inflammation of mucosa in fundus and body of stomach autoimmune destruction of parietal cells producing hcl and if cause low stomach juice acidity (achlohydria which is hi stomach ph) and no IF leading to b12 avitaminosis which leads to pernicious anemia (macrocystic/megaloblastic anemia); giant rbc's type a is autoimmune and anemia |
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type b gastritis |
involves inflammation of mucosa in antrum and pylorus of stomach caused by H pylori infection (surive in high acidity environment of stomach), destroy stomach mucosa type b is bacterial |
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peptic ulcer |
caused by chronic gastritis and loss of mucosa big lesion of mucosa leaving underlying tissues to be digested by stomach acid and enzymes sx: burning/gnawing epigastric pain, nausea, hematemesis (vomiting blood) and melena (blood in stool) PUD include both gastric and duodenal ulcers gastric ulcers vs duodenal ulcers |
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gastric PUD |
Pain worse with meal = incr'd gastric acid pyloric region most common region ulcers can perforate the wall: erosion of gastric arteries post. wall ulcers can erode pancreas can cause hematemesis |
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duodenal PUD |
4 times as many more ulecers here than in stomach. usually benign Pain improves with meal =incr'd duodenal bicarbonate ulcers can perforate wall: erosion of gastroduodenal artery with severe bleeding can cause hematochezia |
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coming down descending aorta we get to celiac trunk |
3 branches off celiac trunk left gastric artery the split between the two other splits that will go up towards left top stomach (cardia) splenic artery the big split going left behind stomach to spleen hepatic artery the big split going to right (medially) |
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left gastric artery |
runs thru lesser omentum and supplies cardia and lesser curvature of stomach (so it comes off celiac trunk, goes up to left top of lesser curve and runs along side cardia and then lesser curvature) it anastomoses on the right after it curves with the right gastric artery |
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right gastric artery |
a branch off the common hepatic artery comes up off hepatic and goes down to lesser curvature to connect with left gastric along the curve |
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left gastro omental (gastro-epiploic) artery |
terminal branch of the splenic artery that supplies the greater curvature of stomach (so it came off splenic which was running behind stomach all the way to lateral left side, it goes down along greater curv) it runs thru greater omentum |
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right gastroomental artery |
terminal branch of hepatic artery that will anastomose with left gastro omental art on greater curvature (it went from common hepatic art to gastroduod art then its the right gastro-omental) |
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common hepatic artery |
Big branch off celiac trunk that goes right
It's branches: the two proximal branches (proximal to celiac trunk-est) right gastric artery (going to lesser curv) gastroduodenal artery that turns into or branches into right gastro-omental artery (going to greater curv)
then distal further from celiac trunk we have branches off hepatic artery- cystic artery, left and right hepatic arteries |
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off the gastroduodenal artery |
right gastro-omental (same as gastroepiploic) superior pancreaticoduodenal |
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mesentery |
double layer of visceral peritoneum holding organ to dorsal wall root of mesentary from left side of L2 to sacroiliac joint mesentary that holds large instestine= mesocolon transverse mesocolon splits the abdominal cavity into supracolic compartment (liver, stomach, spleen) and infracolic (intestines) |
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omentum |
double layer of visceral peritoneum connecting organ to organ "policeman of the abdomen" cuz it can fill voids if something removed/ in the wrong place it's the vascularized fat flap covering intestines first seen on opening abdomen lesser omentum: draping from liver to stomach (so from under liver to lesser curvature of stomach connect) greater omentum: from stomach greater curvature side (underside) and over the segment of colon in upper abdomen |
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duodenum |
first part of small intestine, c shaped part retroperitoneal contains brunner glands: produce mucus rich alkaline secretion that contains bicarbonate and neutralizes acid coming from stomach consists of 4 parts superior descending (where bile enters via sphincter of oddi) horizontal ascending the last 3 parts (everything except superior) have no mesentary and are immobile end of duodenum is a sharp bend known as duodenojejenal flexure |
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jejenum |
thicker and more vascular and redder than duod or ileum mostly lies in umbilical region has highest activity of brush border enzymes responsible for absorption surface increased by presence of many vili and plicae circularis (aka intestinal valves), permanent large, tall closely spaced circular folds running around lumen of jejenum and ileum the jej compared to il: less complex arterial arcades longer vasa recta more plicae circularis, thicker, more highly folded no fat in mesentery |
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ileum |
il compared to jej: longer/more arterial arcades shorter vasa recta less plicae circularis, thinner less folded fat is present in mesentery short fat il kids go to the arcade ileum is last and longest part of small intestine mostly locate in pubic and inguinal region also has plicae circularis, but shorter and less abundant than in jej. peyers patches, characteristic of ileum, clusters of lymphatic nodules seen on side of ileum opposite to mesentery (picture of intestine with white bump thingys) absorption of b12 occur here if removed ileum: pt suffer b12 defic and need injections |
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2 types of movements in small intestine |
segmentations peristaltic waves segmentations: contractions of SM that move chyme in both directions allows greater mixing of chyme with secretions of stomach and intestines peristalsis: begins in duodenum these waves overlap, called migrating myoelectric complex (mmc) which is a kind of peristalsis which pushes the chyme forward |
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ileocecal sphincter or valve |
end of small intestine normally closed connect small intestine end of ileum to beginning or large intestine at ascending colon (right side) and extends in the cecum food filing stomach stimulates gastroileal reflex that is increasing peristalsis and opens the ileocecal valve allowing passage from small int to large int |
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large intestine |
include cecum with appendix (starting on right side) ascending colon transverse colon descending colon sigmoid colon (little dip after went down descending) rectum anal canal absorbs remaining water, compacts feces and houses symbiotic bacteria! |
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cecum |
blind pouch in right lower abdominal quadrant |
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vermiform appendix |
small blind tubule opening into cecum removal doesn't affect health of person |
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hepatic flexure |
aka right colic flexure the 90 degr turn from ascending colon to transverse colon (right side) near the right lobe of liver |
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splenic flexure |
aka left colic flexure transverse colon turn down to descending colon on left side |
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anal canal has two sphincters |
internal sphincter (made of SM) involuntary external sphincter (made of skeletal muscle) under voluntary control |
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muscularis of large intestine |
different from other parts of alimentary canal, instead of a longitudinal external layer, muscularis forms teniae coli |
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teniae coli |
3 separate longitudinal ribbons of SM on outside of ascend,transv, desc, sigm colon (it's the 3 discontinuous bands of longitudinal smooth muscle on exterior) tenia coli shorter than the intestine so colon becomes sacked btwn teniae forming haustra |
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haustra |
small pouches caused by the sacculations of colon between teniae. give colon its segmented appearance! |
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epiploic appendages |
small pouches of peritoneum filled with fat and situated along colon and upper part of rectum |
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the 3 features differentiating large instestine from small instestine |
large instestine has teniae coli haustra epiploic appendages |
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colon motility |
haustral churning most of time haustra relaxed and distended, when distension reaches certain point, smooth musc in haustral wall contract and squeeze contents into next haustra peristalsis moves chyme along ascending colon mass movements more characteristic for transverse and descending parts, strong contractions 3-4 x/day propel contents towards end of colon |
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defecation reflex |
triggered by distension of rectum parasymp stim of lower colon and rectum contractions simultaneously with the relaxation of internal anal sphinct |
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IBD inflammatory bowel disease |
severe chronic and persistent colitis (inflamm of colon) 2 types of IBD: chron's disease ulcerative colitis |
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ulcerative colitis |
inflammation of colon mucosa involves rectum and is continuous without skips disease confined to cololn thin bowel wall (mucosa) disease is continuous (rectum) ulcers do not cross muscularis mucosae granulomas uncommon |
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crohns disease |
autoimmune inflamm degeneration of mucosa and underlying layers severe cases: gut wall perforated and caue fistulas (connect gut with abdominal cavity or outside of body) intestinal wall becomes thicker and may obstruct lumen can affect any part of intestine but most common in distal ileum and proximal colon almost never involves rectum, but can be in anus lesions found anywhere between mouth and anus thickened bowel wall with cobblestone appearance disease occurs in patches: skip lesions deep ulcers that do cross muscularis mucosae granulomas common involves all 4 layers! |
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colon cancer |
second leading cause of cancer related deaths in US risk fx's: IBD, low fiber diet, increasing age, family hx, polyps screening is important two major screening methods: stool occult blood test and colonoscopy |
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stool occult blood test |
quick, cheap, nonspecific test for presence of trace blood in stool if positive go to more specific diagnoses via colonoscopy and biopsy |
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colonscopy |
visual examination of colon with endoscope |
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colectomy |
colostomy bowel resection surgery to remove all or part of large bowel and ileum removal of entire colon and rectum=proctocolectomy or total colectomy remove part: subtotal colectomy |
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diverticulsosis |
out pouching of mucosa due to herniation of mucosa |
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celiac artery (trunk) supplies |
foregut (esophagus, stomach, duod, liver, gall bladder, pancreas, spleen) |
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Superior mesenteric artery (SMA) supplies |
midgut SMA starts at lower duod and has two loops cranial lumb of midgut loop forms jejen, il caudal limb forms il, cec, appendix, ascending and transverse colon (first 2/3) |
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Inferior mesenteric artery (IMA) supplies |
hindgut ima cranial end starts at distal 1/3 of transverse colon, desc and sigmoid colon caudal end: cloacae, rectum, anal canal and urogenital bladder |
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duodenum blood supply |
two sources: proximal part of duodenum (foregut) receives bile and pancr juice from ampulla of vater, receives blood from celiac trunk via gastroduodenal and superior pancreaticoduodenal arteries distal part starting from sphincter of oddi and down receives blood from inferior pancreaticoduodenal arteries which receive blood via SMA |
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superior and inferior pancreaticoduodenal arteries |
form anastomoses btwn celiac trunk and SMA that allows collateral circulation if needed |
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duodenal veins dran to |
portal vein either directly or via splenic and superior mesenteric veins |
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midgut |
jej, il and proximal colon including proximal 2/3 of transverse colon receive blood from SMA that runs within mesentery and gives arterial arcades and vasa recta branches of SMA are named after guts they supply or direction of flow: jejunal, ileal, ileocolic, right colic, middle colic blood from all these intestines drain into corresponding veins: superior mesenteric vein and eventually to portal vein |
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hindgut |
arterial supplly of distal transverse, descending and sigmoid colon from IMA which gives left colic, sigmoid and marginal arteries marginal artery also receives supply from middle colic and forms anastomosis btwn SMA and iMA (infer mesent vein returns blood from descending and sigmoid colon to portal vein) |
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branches of SMA |
[IMRII] inferior PD artery middle colic artery right colic artery ileocolic artery intestinal (jejenal and ileal branches) |
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marginal artery |
anastamoses between middle colic of SMA and left colic of IMA common site for ischemia |
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branches of IMA |
[LSS] left colic artery sigmoid artery superior rectal artery |
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only regions in GI tract that have glands in submucosa |
Esophagus (not as abundant as in-->) Duodenum |
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esophageal muscularis externa |
smooth and skeletal muscles upper part: skeletal lower part: smooth fibers middle: both (these fibers make the internal circular and external longitudinal layers) |
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esophagus serosa vs adventitia |
esoph inside abdominal cavity: serosa covered before esoph passes thru diaphragm its: adventitia covered |
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esophagus characteristics on slide |
lumen lined by thick layer of nonkeratin'd stratified squamous epithelium that normally appears as silky offwhite velvety surface *contain submucosal gland (only other place that also has this..?) |
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gastro esophegeal jxn |
shift from stratified squamous epithelium of esophagus to the simple columnar epithelium of stomach |
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stomach cells and gastric pit |
stomachs rugae are thick folds of mucosa and submucosa internal surface lined with simple columnar epithl and goblet cells invaginations of epithel into mucose are gastric pits/foveolae: regenerative cells (mostly at isthmus, top of pit, top of neck) they divide to replace other cells in gastric glands pareital (oxyntic cells) mostly at neck of pit which is middle way down pit) make HCl and IF cheif cells (zymogenic cells, at base of pit) make pepsinogen and gastric lipase enteroendocrine cells present in most of gi tract make hormones. in stomach make gastrin and histamine g cells make gastrin mucus neck cells produce mucus and bicarbonate, protect stomach epithel from damage by stomach acid. they appear pale and contain obvious mucous droplets |
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if i see glands in the mucosa* |
its the stomach. |
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small intenstine |
most distinctive ft.: large SA bc of plicae circularis (valvs of kerckring, circular folds) permanent transverse folds involving submucosa the actual big fold epithel: simple columnar villi: finger like protrusions of lamina propria the little folds off the big fold core of villus lacteals (lymphatic capillaries) central lymphatic vessel in core of villus (extension of lamina propria (so like opposite of what the folds are cuz its in the middle of fold) crucial for absorption of lipids on slide it looks like white area within fold look at the pic cuz its like big folds and then the little folds along the big fold the little folds are villi its a curvy fold |
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duodenum |
has brunners glands in submucosa (other sections dont) villi in duod are taller, fatter, broader than in other sections |
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jejenum |
NO brunners gland in submucosa NO peyers patces in lamina propria means its jejenum well dvlpd villi more narrow and sparse than in duod and remember, less complex arterial arcades longer vasa recta more plicae circularis, thicker, more highly folded no fat in mesentery |
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ileum |
has peyers patches lamina propria villi in the ileum are shortest and narrowest and remember, more complex arterial arcades shorter vasa recta less plicae circularis, thinner, less folded fat present in mesentery |
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colon (large intest) histology |
surface looks even across crypts all the way down nothing in submucosa no vili goblet cells in epithelium instead of outer longitudinal layer there are teniae coli, the 3 bands |
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barretts esophagus |
weakness of LES so acid from stomach spill up into esophagus charact'd by replacement of stratified squamous epithelium (normal esoph epithel) with columnar epithelium with goblet cells (gastric mucosa) presence of goblet cells is most significant criteria for dx of barretts |
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aplasia |
failure to dvlp something didnt grow in baby |
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heteroplasia |
growth of normal tissue in wrong place |
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metaplasia low grade dysplasia |
metaplasis, low grade dysplasia abnormal transformation of an adult fully differentiated tissue of one kind into differentiated tissue of another kind highly diff replace by highly diff ie barretts esophagus |
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dysplasia aka hi grade dysplasia |
hi grade dysplasia abnormal transformation of highly diff'd into lowly diff'd tissue cells become smaller, nuclei more active, more heterochromatin (char of lowly diff) precancerous condition |
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adenoma |
benign gland like looking tumor |
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adenocarcinoma |
malignant tumor that looks similar to a gland its an adenoma turned cancerous |
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lowly differentiated cancer cells |
high nucleus to cytoplasm ratio more nucleus than cytoplasm heterochromatin rich nuclei that are BIG lots of mitotic figures see dark inside nucleus of cell so darkness taking up most area of cell. |
