Anatomy Block 3 Study Guide Part 2 PDF

Know the blood supply, venous drainage, and innervation of the stomach. Blood Supply of the Stomach Venous Drainage of the Stomach Innervation of the Stomach Celiac Trunk Branches Veins: All blood is drained via Parasympathetic: Left gastric artery...

Know the blood supply, venous drainage, and innervation of the stomach. Blood Supply of the Stomach Venous Drainage of the Stomach Innervation of the Stomach Celiac Trunk Branches Veins: All blood is drained via Parasympathetic: Left gastric artery Portal vein directly (left and right Anterior and posterior vagus trunks, giving Common hepatic artery to right gastric veins) or indirectly through rise to the anterior and posterior gastric gastric artery the splenic vein (the left (Latarget) nerves Common hepatic artery to gastroepiploic vein and short Motor to longitudinal muscles gastroduodenal artery to right gastric veins) Secretomotor to the glands gastroepiploic artery Sensory for gastric re exes Splenic artery to short gastric The right gastroepiploic vein goes Gastric secretion stimulated by neural and arteries and left gastroepiploic to the superior mesenteric vein. mechanic stimulation. Neural stimulation is via the Vagus nerve. artery **Vagotomy is performed for extreme ulcer treatment** Sympathetic: Mostly coming from splanchnic nerves (also from upper lumbar) which synapse in the Celiac ganglion Postganglionic bers innervate the stomach to inhibit peristalsis and gastric secretion, and cause pyloric contraction; they also convey pain What is the Clinical significance of the following: gastric ulcers, vagotomy, and hemigastrectomy? How are all three connected?  Gastric ulcers are due to defective mucosal barrier including the same causes of gastritis; most common on the lesser curvature, has a pain which is increased by eating; no acid or ulcer Vagotomy used for treating the gastric ulcers not responding to drugs Perforation of gastric ulcers is uncommon but, if a posterior gastric ulcer for perforates, it can involve the pancreas resulting in referred pain to the back. Erosion of the splenic artery results in hemorrhage into the peritoneal cavity; eliminates the neural stimulation of gastric secretion. Procedure is known to have complication on gastric emptying Hemigastrectomy: Billroth I and II Pylorectomy removes G cells that secrete Gastrin (controls acid secretion) Know the Clinical significance of the sliding and paraesophagel hiatal hernias, including the unique characteristics for each, and treatment. Hiatal Hernia Protrusion of part of the stomach into the mediastinum through the esophageal hiatus of the diaphragm Often painful and mixed with other chest pains including the cardiac ischemia Two main types: 1. Sliding hiatal hernia: when abdominal part of the esophagus and cardia and even part of the fundus slide up through the esophageal hiatus. *Regurgitation and heart burn 2. Para-esophageal hiatal hernia: Cardia doesn’t move but part of the fundus and peritoneum passes through the esophageal hiatus. *Usually, no regurgitation.  Surgery Reinforces the barrier to re ux that the lower esophageal valve normally provides In most cases, the operation performed to correct gastroesophageal re ux is a procedure called "fundoplication” The upper portion of the stomach (the fundus) is wrapped (plicated) around the lower portion of the esophagus and anchored securely below the diaphragm Radiofrequency Treatment Using an endoscope supplied by electrodes Radiofrequency energy causes tiny burns at G-E junction that heal and form scar tissue that actually tightens the weak valve What is the Clinical significance of hypertrophic pyloric stenosis? Hypertrophic Pyloric Stenosis: progressive hypertrophy of circular muscles in pyloric sphincter, causing a narrow pyloric lumen which may obstruct food passage. This may happen in male infants ( rst child usually) which is associated with projectile, nonbilious vomiting after feeding; palpation reveals a small knot (olive-sized mass) at the right costal margin. Treatment: longitudinal pyloromyotomy, leaving the mucosa intact Know the overall function of the duodenum, the names and locations of the four parts, and the unique characteristics of each. L1-L3 vertebrae and partly to T12 1st or superior part: 5cm long, between T12-L1 This part is anterior to portal vein and Common Bile Duct. Duodenal cap: site of ulcer 2nd or descending part: 7.5 cm long until lower level of L3 Contains a common opening for the common bile duct and the main pancreatic duct in its postero-medial wall major duodenal papilla Within the wall, the common opening is dilated and forms the hepatopancreatic ampulla of Vater which is surrounded by the ampullary sphincter of Oddi The 2nd part has the minor duodenal papilla as well, which is superior to the major opening  3rd or horizontal part: 10 cm, at L3 level Anterior to IVC and abdominal aorta Crossed by superior mesenteric artery and vein anteriorly 4th or ascending part: 2.5 cm long Travels across the midline to the duodenojejunal exure at the L1-L2 Function: Regulates stomach and gallbladder emptying in response to acidic chyme Secretes Secretin due to high acid and fatty acids in its lumen; Secretin inhibits the gastric acid secretion Secretes Cholecystokinin, in response to fatty chyme which induces gallbladder contraction (NOT DONE BY PANCREAS) Secretes the Enterogastrone, that inhibits stomach peristalsis Duodenal Ulcers: Most occur within 5 cm of the pylorus and more frequently on the anterior wall; usually perforates anteriorly 4 times more frequent than gastric ulcers Due to increased acid production of the stomach, pain wakens at night and is relieved by eating Duodenal Atresia: Discontinuity of the lumen owing to failed recanalization (seen sometimes in Trisomy 21) and is associated with polyhydramnios, bile-containing vomitus and distended stomach, double bubble sign Know the innervation of the digestive tract: specifically, the submucosal plexus of Meissner and myenteric plexus of Auerbach. Sympathetic (inhibits) Parasympathetic (stimulates) Submucosal plexus of Meissner: secretomotor function produces mucus for lubrication and facilitates molecule movement. Myenteric plexus of Auerbach: Peristaltic movement of smooth muscle  What is the function of the jejunum and ileum? Function: Absorption of the digested food -Iron is preferentially reabsorbed in the duodenum -Folate in the jejunum -Vitamin B12 in the ileum Small intestine is the only essential part of the GI tract which is essential for life What is the blood supply, venous drainage, and innervation of the small intestine? Blood Supply of the Small Intestine Arteries: Through various branches of the superior mesenteric artery Veins: Blood from small intestine is carried by the superior mesenteric vein into the portal vein and to the liver Innervation of the Small Intestine Sympathetic: Splanchnic nerves via the superior mesenteric and intermesenteric ganglia. Inhibition of peristalsis and contraction of the ileocecal sphincter and vasoconstriction of vessels Parasympathetic: Vagus nerve - causes peristalsis and glandular secretion  What is the Clinical significance of Meckel’s diverticulum? Meckel's Diverticulum: An ileal outpocketing typically located with in 50-75 cm (40 cm in newborn) of the ileocecal valve -This is a congenital anomaly resulting from persistence of the vitelline (omphalomesenteric) duct. It might be free (74%) or attached by a chord to the umbilicus -May mimic pain of appendicitis -About half of them cause ulceration, in ammation, and GI bleeding because of the presence of ectopic acid-secreting gastric epithelium; pancreatic tissue may also be present there -Rule of 2's: occurs in about 2% of children, 2 feet from the ileocecal valve, contain 2 types of ectopic mucosa (gastric and pancreatic), usually occurs at 2 years of age Know the location and function of the vermiform appendix. What is the Clinical significance of an appendicitis, including treatment? Vermiform Appendix Narrow, hollow and muscular structure arising from the posteromedial aspect of the cecum about 2-3 cm below the ileocecal junction 0.5 cm to even 25 cm long (9-10 cm in average), has a smooth appearance, with large accumulations of lymphatics in the mucosa and the submucosa Lumen is 6-8mm wide in young children and gets narrower in adulthood May be occluded by a fecalith or in ammation and edema of the lymphatic tissue leading to acute (acute abdomen) and chronic appendicitis Pain is preumbilical at T10 dermatome (sympathetic) Appendectomy using the McBurney's point between umbilicus and right anterior superior Iliac spine (junction between right 1/3 and mid 1/3). The Iliohypogastric nerve should be saved, if not, muscle weakness and direct Inguinal hernia may result Appendicitis: A condition in which the appendix becomes in amed and lled with pus, causing pain. The appendix is a pouch on the colon that has no known purpose. Symptoms: begins with pain near the belly button and then moves to the right side. This is often accompanied by nausea, vomiting, poor appetite, fever, and chills. Treatment: surgery and antibiotics. If untreated, the appendix can rupture and cause an abscess or systemic infection (sepsis).  Know the Blood supply and venous drainage of the colon. Blood Supply of the Colon Branches of superior and inferior mesenteric arteries Ileocolic artery, cecal artery, appendicular, right colic, and middle colic arteries Marginal Artery of Drummond is formed by anastomosis of various branches of the superior and inferior mesenteric arteries. It lies in the mesentery close to the colon and is an important anastomosis if one of these arteries is blocked Venous drainage: Colic veins - Superior Mesenteric veins - Portal vein What is the clinical significance of the pectinate line of the anal canal? Rectum is continuous with the anus. Anal canal is the terminal part of the large intestine that extends from the upper part of the pelvic diaphragm to the anus Anal canal is 2.5-3.5 cm long. The inferior comb shaped limit of the anal valves forms the Pectinate line This indicates the junction of the superior part of the anal canal (derived from the hind-gut) and the inferior part (derived from the proctodeum) Know the blood supply, venous drainage, and innervation of the rectum and anus. Blood Supply of the Rectum and Anus 1- Superior rectal artery: the nal branch of the inferior mesenteric artery supplies the superior part of the rectum 2- Middle rectal artery: from internal iliac artery supplies the middle 3- inferior rectal artery: a branch of the internal pudendal a. which is also coming from internal Iliac artery supplies the lower part of the rectum The veins follow the same names. Superior rectal vein drains into the inferior mesenteric vein and then into the portal vein Middle and inferior rectal veins drain into the internal iliac vein. *Portocaval anastomosis Innervation of the Rectum and Anal Canal Sympathetic: from lumbar part of the trunk through the superior hypogastric plexus. Parasympathetic: S2, S3 and S4 called the pelvic splanchnic nerves They run into the inferior hypogastric plexus and are only sensitive to stretching Inferior to the pectinate line: by inferior rectal nerve, a branch of the pudendal nerve (somatic innervation, sensitive to pain, touch and temperature)  Know the Clinical significance of the Portocaval anastomosis. Abdominal organs and structures either drain their blood directly into the IVC or indirectly by rst draining into the portal vein and then through the liver for “ ltering” before reaching the IVC via the hepatic vein. Portal Vein - Portal System IVC - Caval System PCA is a connection with the two systems. There are 7 PCAs, but only 3 are commonly used Clinically. Know the differences between internal and external hemorrhoids. Prolapse of Hemorrhoids The veins under the mucosa of the anus are normally dilated and produce the internal and external rectal venous plexus Internal hemorrhoids (Piles): prolapses of rectal mucosa containing superior rectal veins. They occur above the pectinate line. Painless bleeding, autonomic nerve supply External hemorrhoids: are thromboses (blood clots) in the veins of the external rectal plexus (inferior rectal veins) and are covered by the skin. They occur below the pectinate line and are painful. Somatic innervation, (inferior rectal branch of the pudendal nerve) Predisposing factors: pregnancy, chronic constipation, increased intra-abdominal pressure What is the Clinical significance of Hirschsprung’s disease? CONGENITAL MEGACOLON De ciency of ganglion cells in Meissner's submucosal plexus and Myenteric plexus of Auerbach (failure of migration of the neural crest cells to the Myenteric plexus) Associated with down syndrome and Chagas disease. 90% restricted to the rectum. Bowel is dilated proximal to the defect, inability of peristalsis to push the stool beyond the aganglionic segment. Presents with fecal retention and abdominal distention; this is a functional, not anatomical obstruction. Diagnosis is by rectal biopsy.  Know the overall functions of the liver. Function: Bile production (bile pigments are the end products of hemoglobin catabolism) - Bile accumulates in the gall bladder and is discharged into the duodenum as needed - Bile acids emulsify fat Involved in carbohydrate and protein metabolism and storage of various substances such as glycogen Vitamin and protein production Detoxi cation of drugs Within the liver lobules, know the location, importance, and function of the following: Glisson’s triad, Disse’s space, Ito cells, and hepatocytes. Hexagonal in shape and composed of liver cells (hepatocytes) GLISSON'S TRIAD- Surrounded by branches of the portal vein, hepatic artery, and bile duct Blood from portal vein and hepatic arteries drain into sinusoids where it is ltered Digested materials can be stored or used in anabolic processes; detoxi cation occurs as needed Filtered blood is drained into the central vein Central veins pass blood into the hepatic vein and on to the IVC Disse’s space, (fat storing Ito cells are found here)- Space between the vessel wall of the sinusoids and the surface of the liver cell Hepatocytes have big nuclei and more than 2500 SER per cell needed for detoxi cation RER is responsible for protein production http://eclinpath.com/chemistry/liver/liver-structure-and-function/liverlobule/ WATCH VID: https://ucf.zoom.us/rec/play/-7BVUjcOjPL3cVfAYNIG9- FiwAvdBVQySqaxwsz5SDmVBtBrf- He9NnJk06sX90Tt6MU2hVYh2ajsayP.kSUap5620eH6m1Sq? canPlayFromShare=true&from=share_recording_detail&continueMode=true&componentNam e=rec- play&originRequestUrl=https%3A%2F%2Fucf.zoom.us%2Frec%2Fshare%2FsiuQ8M5kkp9 G3sZOJBBE5T4DlJTa3qROUakMSPDeq0E6P8cGLadllR0dXRmmtleK.2zA_tyONKG6u9jJP (STARTS AT 21:00)  What is the Clinical significance of Cirrhosis of the Liver? Cirrhosis of the liver: persistent in ammatory reaction and progressive destruction of the liver due to necrosis and replacement by brosis and compensatory hyperplasia Causes: Alcoholic liver disease, post-necrotic following viral hepatitis, and iron overload of the liver Liver becomes hard as a result of brosis, blood ow through liver is compromised Results in portal hypertension (40-45 mmHg), bleeding esophageal and rectal varices Portocaval shunt (anastomosing the portal vein to IVC) is a possible surgical therapy If the cause of damage is removed early enough, liver tissue is able to regenerate itself. Regeneration can also take place after hepatectomy. Understand the development, diagnosis, and treatment of gallstones. What is a significant secondary condition that can be caused as a result of gallstones? Gall stones (cholelithiasis): formed due to an imbalance in the concentration of cholesterol and bile salts in the bile; precipitation of the salts or cholesterol leads to stone formation **5Fs: Female, Fertile, Fourty/ fty, Full- gured, and Fair Sites of Gallstone Impaction: distal end of the hepatopancreatic ampulla of Vater (jaundice and pancreatitis) and Hartmann’s pouch; pain in the epigastric region (biliary colic) Secondarily, can cause pancreatitis. How? Treatment: diet modi cations (no symptoms) or surgery to remove gallbladder Acute Cholecystitis: acute in ammation of the gallbladder wall, usually due to cystic duct obstruction by a gallstone. Bile accumulation in the gallbladder, enlargement, and pain in epigastric and right hypochondriac regions in transpyloric line, nausea, vomiting. Painful splinting of respiration during deep inspiration in right upper quadrant palpation (Murphy's sign) Cholecystectomy: removal of the gallbladder due to severe biliary colic, cystic duct obstruction or cholecystitis