Week 8- LO's

List the layers of the anterolateral abdominal wall starting from the skin and ending with the peritoneum; include individual muscles in the list.

-Skin -Camper's fascia (which is mainly fat) -Scarpa's fascia (which is deeper connective tissue, and is a good spot for suturing) -External abdominal oblique -Internal abdominal oblique -Transversus abdominis -Transversalis fascia -Parietal peritoneum

Trace the flow of bile from the gallbladder to the duodenum.

Gallbladder --> Cystic Duct --> Common Bile Duct --> Sphincter of Oddi (at Major Duodenal Papilla) --> Duodenum

Identify the surface anatomy associated with the T6, T10, and L1 dermatomes.

-T6 dermatome = at xiphoid process To remember, this that "x" is in both "six" and "xiphoid". -T10 dermatome = at umbilicus (belly button)To remember, think "belly butTEN" -L1 dermatome = inguinal ligament To remember, think "inguinaL 1igament"

List the structures that enter/exit the liver through the porta hepatis.

Porta Hepatis Structures: o Right & Left Hepatic Arteries o Right & Left Hepatic Ducts o Hepatic Portal Vein o Autonomic Nerves o Lymphatics

Describe the developmental basis of the following abnormalities of the GI tract: Tracheoesophageal Artesia and Fistulas

Abnormalities in partitioning of the esophagus and trachea result in esophageal atresia with or without tracheoesophageal fistulas (TEFs). Several varieties of this type of defect may develop, but the most common anomaly is for the superior esophagus to end blindly (esophageal atresia) and for the inferior part to join the trachea near its bifurcation. Infants with this anomaly cough and choke when swallowing because of the accumulation of excessive amounts of saliva in the mouth and upper respiratory tract. When the infant attempts to swallow milk, it rapidly fills the esophageal pouch and is regurgitated. Polyhydramnios (excess amniotic fluid) is often associated with these types of defects because amniotic fluid cannot pass to the fetal stomach and intestines for absorption and subsequent transfer through the placenta.

Describe the developmental basis of the following abnormalities of the GI tract: volvulus

Abnormally positioned intestinal loops are prone to twisting around their mesenteries (volvulus), which can interrupt blood supply or venous/lymphatic drainage.

Trace the flow of bile from the liver to the duodenum.

Liver --> Right & Left Hepatic Ducts --> Common Hepatic Duct --> Common Bile Duct --> Sphincter of Oddi (at Major Duodenal Papilla) --> Duodenum

Describe the developmental basis of the following abnormalities of the GI tract: gastroschisis

Failure of the opposing sides of the body wall to fuse in the anterior midline can result in a variety of closure defects. Gastroschisis refers to the condition in which abdominal contents herniate through an opening lateral to the umbilicus.

Explain where excess fluid will likely pool/collect in the peritoneal cavity when in a supine position versus the erect position.

Fluid will most of the time collect in the hepatorenal recess, since it is the lowest point of the peritoneal cavity. o Hepatorenal recess is the space between the bottom of the liver and the top of the kidney. Fluid from the lesser sac can drain and pool here - In the supine patient excess fluid in the abdomen will flow to the hepatorenal recess (Morrison's pouch; see Moore Fig. 5.64E below). In an erect position - In the erect patient excess peritoneal fluid or other fluids will flow to these rectrovesical or rectouterine pouches.

Compare the definitions of the terms "intraperitoneal" and "retroperitoneal" and list the viscera that belong in each category.

"Intraperitoneal" means organs which are fully covered with visceral peritoneum. They are NOT DIRECTLY in the peritoneal cavity; just pushed far enough into it so that they're completely enveloped with the visceral peritoneum. - suspended by mesentery Organs like this are: SALTD SPRSS: o Stomach o Appendix o Liver o Transverse colon o Duodenum (1st part only, bulb) o Small intestines (jejunum and ileum) o Pancreas (tail) o Rectum (only upper 3rd) o Spleen o Sigmoid colon "Retroperitoneal" means organs which are only covered by peritoneum on the anterior side. These organs are like the intraperitoneal ones in that they're in the same level of fascia, however these organs don't push that far into the peritoneal cavity, so they aren't fully covered with visceral peritoneum. - Never invested by a DORSAL MESENTERY during fetal development - Examples are: SAD PUCKER o Suprarenal glands o Aorta/ IVC o Duodenum (2nd-4th Part) o Pancreas (head and body) o Ureters o Colon (ascending and descending) o Kidneys o Esophagus (thoracic) o Rectum "Secondarily retroperitoneal" means organs that had a mesentery, but lose it during development. - Organs in this group are: MAD House o Most of duodenum o Ascending colon o Descending colon o Head, neck, and body of pancreas

List the structures derived from the foregut

(Give rise to Upper GI Tract): o Pharynx o Esophagus o Stomach o Proximal Duodenum o Liver o Gallbladder o Pancreas

Specify the location of the gut tube pain line and explain its significance with respect to the pathways visceral pain information from the GI tract and accessory organs is projected to the CNS; relate this information to the dermatomes and regions of the body wall to which visceral pain from GI organs can be referred.

- Although visceral pain from most viscera travels retrograde along sympathetic routes, pain from viscera located deep in the pelvic cavity travel retrograde along parasympathetic routes. With respect to the abdominopelvic viscera of the GI tract, the line of demarcation between sympathetic and parasympathetic visceral pain routes (i.e., the "gut tube pain line") is the midpoint of the sigmoid colon. Visceral pain sensation from abdominal GI viscera located proximal to the midpoint of the sigmoid colon travels retrograde along sympathetic routes; visceral pain from the distal half of the sigmoid colon, the rectum and the portion of the anal canal derived from the hindgut portion of the embryonic gut tube travels retrograde along parasympathetic routes. Visceral pain sensation from the latter organs will return via the pelvic splanchnic nerves to the S2-S4 regions of the spinal cord and will therefore be referred to the S2-S4 dermatomes of the body wall (anal region and genitalia). The foregut, midgut, and hindgut organs proximal to the gut tube pain line have distinct sympathetic supplies and therefore distinct patterns of referred pain.

Define a mesentery and describe what types of structures may travel within them.

- Double folded portions of peritoneum - They hold viscera in the abdominal walls - They contain blood vessels, nerve fibers, and lymphatics - 3 main mesenteries 1.) Mesentery proper (1) - Ileum and jejunum - The root forms the dividing plane between right and left infracolic space Mesentery of the large intestine 2.) Mesoappendix (2) 3.) Mesocolon (3) - Mesentery of transverse and sigmoid colon

Describe the division of the peritoneal cavity into greater and lesser sacs and the locations of the epiploic foramen and the lesser sac.

- Greater sac is the largest part of the peritoneal cavity. It has all the organs in the main abdomen (pretty much everything we'd see if we looked through the skin). - The transverse colon divides it into the supra-colic and infra-colic compartments - Lesser sac is the posterior part of the abdominal cavity, behind the stomach. It's a small space, and can be called the omental bursa. It contains the kidneys. - The epiploic foramen is a passageway from the greater sac (front of abdomen) to the lesser sac (back of abdomen). It is formed form the right-most edge of the lesser omentum, the bottom-right part of the liver, and the top of the transverse colon.

Explain the anatomical basis of the Valsalva maneuver and relate that to changes in intra-abdominal pressure.

- The Valsalva maneuver is when we contract our abdominal muscles while holding our breath. This helps with a few functions, like "bearing down" when trying to pass a bowel movement or urinate. - The idea is that usually, contracting our abdominal muscles occurs when in exhale. However, since we're holding our breath, the muscles contract, but the diaphragm isn't moving, so pressure builds, which allows us to pass a bowel movement or urinate. - On the other hand, it also helps see how our well our heart is working. For instance, when a patient has a condition called super ventricular tachycardia, this means that the heart rate is about 180 bpm or more (I believe). We may ask the patient to "bear down" to see if this helps lower the heart rate, since doing so puts pressure on the heart, which helps "slow it down".

Specify the organs where major anastomoses between the celiac trunk and the superior mesenteric artery occur and where the anastomoses between the superior mesenteric artery and inferior mesenteric artery occur.

-Anastomoses of Celiac Trunk and Superior Mesenteric Artery - Branches of the Celiac Trunk circulation anastomose with branches of the Superior Mesenteric Artery in the Pancreas. -Superior & Inferior Mesenteric Artery Anastomosis - The anastomosis between the middle colic artery of the superior mesenteric artery with the left colic artery of the inferior mesenteric artery occurs along the margin of the distal portion of the transverse colon and splenic flexure. a. In the pancreas, the gastroduodenal artery (celiac trunk) will anastomose with branches of the superior mesenteric artery in the pancreas b. Along the margin of the distal portion of the transverse colon and splenic fixture, the middle colic artery (a branch of the superior mesenteric artery) will anastomose with the left colic artery (a branch of the inferior mesenteric artery)

Specify the main branches of the aorta which supply the foregut, midgut, and hindgut regions of the gut tube.

-Foregut - Celiac Trunk of the Abdominal Aorta -Midgut - Superior Mesenteric Artery -Hindgut - Inferior Mesenteric Artery

Specify the abdominal quadrant(s) in which the following structures are located: liver, gallbladder, stomach, pancreas, spleen, cecum, appendix, descending colon, sigmoid colon.

-Liver: RUQ/LUQ -Gallbladder: RUQ -Stomach: LUQ -Pancreas: LUQ/RUQ -Spleen: LUQ -Appendix: RLQ -Descending colon: LLQ -Sigmoid colon: LLQ -Cecum- RLQ

Describe the developmental basis of the following abnormalities of the GI tract: annular pancreas

An annular pancreas is an anomaly in which malrotation of the ventral pancreatic bud, or independent rotation of the two halves of a bifid ventral pancreatic bud, result in the duodenum being completely encircled by pancreatic tissue (See Larsen Fig. 14.11 below). In most cases the amount of pancreatic tissue encircling the duodenum is small and the condition is asymptomatic. However, in some cases the annular pancreas constricts or completely obstructs the lumen of the duodenum. Infants with annular pancreas may cry, spit up more than normal, and be unable to drink enough formula or breast milk. As with pyloric stenosis, the vomitus associated with this condition is typically non-bilious.

Describe how abdominal aponeuroses relate to one another in the arcuate line

Arcuate line is the line at the bottom of our abs where the posterior rector sheath is. It's the entry for arteries into the rectus sheath

Describe the developmental basis of the following normal features of the GI tract: lesser omentum

Formed by the free, inferior edge of the ventral foregut mesentery. The Liver grows rapidly, pressing against the body wall, and obliterating layers of peritoneum. These changes produce this almost separate pocket behind the stomach, the lesser sac. This part of the ventral mesogastrium is the lesser omentum.

Explain the nervous control of defecation and specify the muscles and somatic nerves involved; distinguish the roles of sympathetic and parasympathetic nerves in this process.

As the distal rectum widens from fecal matter, a parasympathetic response occurs to relax the internal anal sphincter, which gets the fecal matter from the rectum to the anal canal. At the same time, stretch receptors in the distal rectum (visceral afferents) trigger us to feel full, where we then make a conscious decision to void or hold. If we decide to void, then our external anal sphincter and pelvic diaphragm relax while our abdominal muscles contract (like the Valsalva maneuver) If we decide to hold, then our external anal sphincter contracts, which is done by the inferior rectal branch of the pudendal nerve Defecation is initiated when feces is driven into the distal rectum by mass colonic contractions. Upon distension of the rectal ampulla a reflex contraction of the rectum occurs, the internal anal sphincter (normally maintained by the sympathetic system in a contracted state) relaxes in response to parasympathetic stimulation, and the fecal material is pushed into the anal canal. Stretch receptors in the distal rectum signal (via visceral afferent fibers) that it is full and the conscious decision is made whether to expel the feces by simultaneously relaxing the external anal sphincter and pelvic floor, and contracting the abdominal musculature, or to postpone defecation by contracting the external anal sphincter (inferior rectal branch of pudendal nerve). In the case of the latter decision, active contraction of the external anal sphincter is required only until colonic contractions cease and retrograde rectal peristalsis moves feces out of the distal rectum.

Specify the lymph pathways and the lymph node groups involved in the spread of pathology from foregut, midgut and hindgut viscera.

At the base of each of the three unpaired branches of the abdominal aorta is a collection of lymph nodes (celiac nodes, superior mesenteric nodes, inferior mesenteric nodes). These lymph nodes screen & filter the lymph collected from tissues along that specific artery's distribution route. Once filtered, the lymph collected from the various regions of the GI tract drains to intestinal lymphatic trunks (trunks = large lymphatic vessels). Only some of the lymph collected from the rectum drains via inferior mesenteric lymphatic routes & inferior mesenteric lymph nodes. The remainder of the lymph from the rectum, & lymph from the hindgut-derived portion of the anal canal as well, drains to lymphatic vessels & lymph nodes located along the courses of the internal iliac & common iliac vessels. These lymphatic vessels drain superiorly via lymphatic vessels on either side of the abdominal aorta & eventually coalesce into large lumbar trunks just inferior to the aortic hiatus.

Explain the anatomical basis of caput medusae and specify the veins involved in each.

Caput Medusae (Paraumbilical Varices) - Caused by Portal Hypertension at the anastomosis between Paraumbilical Veins and the Hepatic Portal Vein. This Anastomosis links the Inferior and Superior Epigastric Veins, Internal Iliac Veins, and Superficial Epigastric Vein to the Hepatic Portal Vein. Displays as visibly dilated veins around the Umbilicus.

Explain the anatomical basis of esophageal varices and specify the veins involved in each.

Cause by Portal Hypertension which results in enlarged veins of the Esophageal Anastomosis. These are the Left Gastric Vein of the Portal System and Esophageal Vein, which drains in Azygos vein of Caval System. These enlarge veins can hemorrhage which is difficult to control surgically and can be life threatening. Commonly develop in individuals with alcoholic Cirrhosis of the Liver. When the hepatic portal vein is congested, blood cannot be drained into the IVC like normal. Then, since the veins are valveless, the blood is pushed into the left gastric vein (among other veins), which will then go to the distal esophagus. The blood then keeps getting pushed through the esophageal veins and be pushed into azygos system of veins. This pushing and high pressure will cause the veins to swell.

Distinguish the caval venous system from the (hepatic) portal venous system.

Caval (Systemic) Venous System - The systemic venous system that drains into the Inferior Vena Cava. Includes blood from the lower libs, pelvic viscera, kidneys, posterior abdominal wall, and all blood inferior to the Thoracoabdominal Diaphragm will drain into the Inferior vena Cava. (Hepatic) Portal Venous System - A group of veins that drain the digestive tract organs and transport that blood into the Liver. Blood from the Portal System will drain into the Caval system after it passes through the Liver.

Specify the pre-aortic (prevertebral) ganglia that contain the postganglionic sympathetic neuronal cell bodies that supply the foregut components of the GI system and the kidneys.

Celiac Ganglia of the Celiac Plexus

Trace the path of a bolus from the esophagus to the rectum, listing in order all components of the gastrointestinal tract through which it will pass.

Esophagus -> lower esophageal sphincter -> cardia of stomach -> body of stomach -> pyloric sphincter -> superior duodenum -> descending duodenum -> transverse duodenum -> ascending duodenum -> jejunum -> ileum -> ileocecal junction->> cecum -> ascending colon -> hepatic flexure -> transverse colon -> splenic flexure -> descending colon -> sigmoid colon -> rectum -> anus

Compare internal and external hemorrhoids in terms of location and the veins involved; compare the signs & symptoms of the different types of hemorrhoids and specify the risk factors that lead to their development. EXTERNAL HEMORRHOIDS

External Hemorrhoids - Caused by blood clots in the external rectal venous plexus veins. This causes swelling/irritation inferior to the Pectinate Line, which is very painful due to somatic sensory innervation.

Describe the developmental basis of the following abnormalities of the GI tract: omphalocele

Failure of the intestinal loops to return to the abdomen results in an omphalocele. This large protrusion of the umbilicus consists of intestinal loops covered by amnion. Rotational errors produce abnormalities in organ position. Two of the most common are non-rotation (initial 90º rotation occurs, 180º rotation does not, producing a "left-sided colon") and reversed rotation (90º rotation occurs, 180º rotation is reversed in direction causing the transverse colon to pass behind the duodenum). Abnormally positioned intestinal loops are prone to twisting around their mesenteries (volvulus), which can interrupt blood supply or venous/lymphatic drainage Note: Failure of the intestinal loops to return to the abdomen results in an omphalocele. In this form of body wall defect intestinal loops, and perhaps stomach and liver as well, protrude through an opening in the umbilical cord. Unlike in gastroschisis, where the herniated abdominal viscera have no covering membrane due to the failure of the abdominal wall and peritoneum to form properly, in omphalocele the herniated abdominal viscera are covered in shiny peritoneum..

Describe the developmental basis of the following abnormalities of the GI tract: Meckel's (ileal) diverticulum

Normally, the connection between the ileum and umbilicus (vitelline duct) degenerates during development. In approximately 2% of the population, a remnant of the duct persists, forming an ilieal (Meckel's) diverticulum. This diverticulum, which may contain gastric or pancreatic tissue, is found within two feet of the ileocecal valve, is typically two inches in length and typically presents symptomatically before the age of two years ("rule of 2's"). Clinical complications can occur if this tissue secretes hydrochloric acid (ulcer, bleeding, inflammation), if an intestinal loop becomes wrapped around the vitelline ligament (intestinal obstruction) or if a fistula is present (resulting in fecal material passing through the umbilicus). Inflammation of an ilieal diverticulum produces symptoms similar to appendicitis.

List the structures derived from the hindgut region of the embryonic gut tube.

o Distal 1/3 rd of Transverse Colon o Descending Colon o Sigmoid Colon o Rectum o Upper Anal Canal (Superior 2/3rds of the adult Anorectal Canal)

Specify the contents of the hepatoduodenal ligament; specify the relationship of the hepatoduodenal ligament and its contents to the omental foramen.

Hepatoduodenal Ligament Contents: o Proper Hepatic Artery o Bile Duct o Hepatic Portal Vein Minor Contents: - Autonomic Nerve Fibers - Lymph Nodes - Lymph Vessels Omental Foramen Relationship: o The hepatoduodenal ligament forms the anterior boundary of the omental foramen and transmits structures to and from the "porta hepatis" (doorway) of the liver.

Describe the developmental basis of the following abnormalities of the GI tract: imperforate anus.

Imperforate anus includes a spectrum of defects that can range from a simple membrane covering the anal opening (persistence of the anal membrane) to atresia of varying lengths of the anal canal, rectum, or both. In many cases anal atresia is accompanied by a rectal fistula linking the patent portion of the hindgut to a structure derived from the urogenital sinus (i.e., vagina, urethra, or urinary bladder). Any examination of a newborn must include a determination of the presence of an anal opening.

Describe the anatomical basis of renal vein entrapment syndrome and relate this to its common symptoms.

In renal vein entrapment syndrome ("nutcracker syndrome") compression of the left renal vein by the overlying superior mesenteric artery can lead to hematuria or proteinuria (blood or protein in the urine), left flank pain, and in males left testicular pain due to the normal drainage of the left testicular vein to the left renal vein. Nausea and vomiting may be involved if the duodenum is also compressed.

Describe how abdominal aponeuroses relate to one another in the rectus sheath

In the rectus sheath: -External oblique aponeuroses go on top -Internal oblique goes on top and bottom -Transversus abdominis goes on bottom

Specify the structures of the abdominopelvic GI system supplied by specific branches of the inferior mesenteric arteries.

Inferior Mesenteric Artery Branches: • Left Colic Artery: o Descending Colon • Sigmoidal Arteries: o Sigmoid Colon • Superior Rectal Artery: o Rectum

Specify the pre-aortic (prevertebral) ganglia that contain the postganglionic sympathetic neuronal cell bodies that supply the hindgut components of the GI system and the kidneys.

Inferior Mesenteric Ganglia of the Aortic Plexus

Compare internal and external hemorrhoids in terms of location and the veins involved; compare the signs & symptoms of the different types of hemorrhoids and specify the risk factors that lead to their development. INTERNAL HEMORRHOIDS

Internal Hemorrhoids - A prolapse of rectal mucosa containing internal rectal venous plexus veins. These veins are normally dilated but portal hypertension can make them varicose. They can become strangulated and ulcerated if compressed by sphincter muscles. They will bleed bright red; however, they will not be painful if they are located superior to the Pectinate Line of the anal canal because of its visceral innervation.

Compare internal and external hemorrhoids in terms of location and the veins involved; compare the signs & symptoms of the different types of hemorrhoids and specify the risk factors that lead to their development.

Internal hemorrhoids are mucosa-covered prolapses of the normally varicose-appearing veins of the internal rectal venous plexus draining blood from the anal canal. Internal hemorrhoids occur because of a breakdown of the muscularis mucosae of the anal canal Week 8 Assignments Page 13 of 24 wall. Initially contained within the anal canal, with enlargement internal hemorrhoids may extrude through the anus on straining during defecation. Bleeding from internal hemorrhoids is common, but pain is not a typical symptom due to the autonomic innervation of the anal canal mucosa. External hemorrhoids are thromboses (blood clots) in the external rectal venous plexus that drains the inferior part of the anal canal. External hemorrhoids are covered by anal skin and are painful, but they usually resolve within hours, often by rupturing. Local anesthetics or sitting in a warm bath often brings relief.

Specify the structures of the abdominopelvic GI system supplied by specific branches of the superior mesenteric arteries.

Intestinal Arteries: o Jejunum o Ileum Ileocolic Artery: o Ileum o Cecum o Ascending Colon Right Colic Artery: o Ascending Colon Middle Colic Artery: o Proximal 2/3 of Transverse Colon

Describe the developmental basis of the following normal features of the GI tract: falciform ligament

It is a remnant of the embryonic ventral mesentery. The umbilical vein of the fetus gives rise to the round ligament of liver in the adult, which is found in the free border of the falciform ligament. The Falciform Ligament is a remnant of the Umbilical Vein ventral mesentery of the liver actually round ligament is from umbilical vein

Describe the organization and boundaries of the abdominal cavity and its relationship to the pelvis including key bony features and surface landmarks.

It is bound by: Thoracic diaphragm (roof) Pelvic diaphragm (floor) Anterior body wall (front) Posterior body wall (back) The abdominopelvic cavity is separated by the pelvic inlet (or brim), which separates the abdomen from the pelvis. It sort of it like the superior thoracic aperture (a large opening or hole). The walls of the abdominopelvic cavity are composed of protective rigid bones superiorly (i.e., inferior thoracic cage) pubic symphysis-> sacral promontory = inferior border of abdominal cavity, beginning of the pelvic cavity

Relate sympathetic and parasympathetic motor pathways to the transmission of visceral sensation to the central nervous system (CNS).

Just like somatic sensory neuron cell bodies, visceral sensory neuron cell bodies are located in a DRG. However, these visceral sensory neurons provide information about our body's internal environment instead of our body's external environment. In addition, visceral sensations are difficult to localize unlike somatic sensations. For example, radiating pain in the upper limb might be pain from your heart (visceral) and not actually musculoskeletal (somatic) in nature. If visceral pain is evident, it could indicate stretching (e.g. colic distentions), tumor impingement, spasms, or contractions (e.g. uterine contractions), infection, and chemical irritation. Visceral afferent neurons are NOT considered part of the autonomic nervous system because they are not classified as sympathetic or parasympathetic. However, visceral afferent fibers do accompany parasympathetic (especially the Vagus nerve) and sympathetic efferent fibers as they travel back to the CNS for the information to be processed. Visceral sensation travels back the same pathways as the sympathetic and parasympathetic nervous system. Therefore, visceral sensation can only be felt on the dermatomes of the associated spinal cord levels. These levels are T1-L2 (3) and S2-S4.

Explain the anatomical basis of the varied referred pain patterns of the pancreas.

Pancreatic pain is usually perceived as a severe discomfort in the epigastric region. Due to the deep placement of the pancreas in the abdomen, pancreatic pain will often radiate to the back. Regardless of its location, pancreatic pain is often described by patients as "drilling/boring" pain.

Explain the anatomical basis of anorectal varices and specify the veins involved in each.

Portal blockage will cause blood to flow from the portal vein, to the splenic veins backing up into the rectum, which forces it up the inferior middle rectal veins through the caval, back to the heart. The pressure will cause the inferior middle rectal veins to swell and will cause hemorrhoids

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: inferior mesenteric ganglia

Postganglionic sympathetic neurons for Lumbar Splanchnic Nerves. Additionally, postganglionic sympathetic neurons for structures of the Hindgut which receive preganglionic signals from the T12-L2/L3 levels.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: inferior hypogastric plexus

Postganglionic sympathetic neurons for Sacral Splanchnic Nerves. Additionally, postganglionic parasympathetic neurons for Pelvic Splanchnic Nerves. All body cavity viscera located inferior to the thoracic diaphragm are innervated by the pre-aortic and inferior hypogastric plexuses of autonomic nerve fibers located in the abdomen and pelvis, respectively. In the abdomen the single (unpaired) pre-aortic plexus extends the full length of the abdominal aorta and terminates inferior to the aortic bifurcation as the superior hypogastric plexus. In the pelvis, right and left inferior hypogastric plexuses are located on either side of the centrally-located pelvic viscera. The pre-aortic and inferior hypogastric plexuses are continuous through the right and left hypogastric nerves

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: aorticorenal ganglia

Postganglionic sympathetic neurons for Thoracic Splanchnic Nerves. Additionally, postganglionic sympathetic neurons for structures of the Midgut which receive preganglionic signals from the T10-T12 levels.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: celiac ganglia

Postganglionic sympathetic neurons for Thoracic Splanchnic Nerves. Additionally, postganglionic sympathetic neurons for structures of the Foregut which receive preganglionic signals from the T5-T9/T10 levels.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: superior mesenteric ganglia

Postganglionic sympathetic neurons for Thoracic Splanchnic Nerves. Additionally, postganglionic sympathetic neurons for structures of the Midgut which receive preganglionic signals from the T10-T12 levels.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: superior hypogastric plexus

Postganglionic sympathetic neurons for structures of the Hindgut which receive preganglionic signals from the T12-L2/L3 levels. Where the Hypogastric Nerves originate.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: hypogastric nerves.

Preganglionic parasympathetic fibers destined to innervate hindgut viscera ascend within the hypogastric nerves to distribute with branches of the inferior mesenteric artery.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: lumbar splanchnic nerves

Preganglionic sympathetic fibers carried within lumbar splanchnic nerves are derived from neurons located in the L1-L2/L3 spinal cord; they synapse on postganglionic sympathetic neurons located in the inferior mesenteric ganglia.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: sacral splanchnic nerves

Preganglionic sympathetic fibers carried within sacral splanchnic nerves are derived from neurons located in the L1-L2/L3 spinal cord; they synapse on postganglionic sympathetic neurons located in the inferior hypogastric plexus.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: thoracic splanchnic

Preganglionic sympathetic fibers carried within thoracic splanchnic nerves are derived from neurons located in the T5-T12 spinal cord; they synapse on postganglionic sympathetic neurons located in pre-aortic ganglia of the celiac plexus (i.e., celiac, aorticorenal and superior mesenteric ganglia).

Specify the pre-aortic (prevertebral) ganglia that contain the postganglionic sympathetic neuronal cell bodies that supply the midgut components of the GI system and the kidneys.

Primary in Superior Mesenteric Ganglia but also in the Aorticorenal Ganglia both of which are part of the Celiac Plexus

Describe the developmental basis of the following abnormalities of the GI tract: pyloric stenosis

Pyloric stenosis is the narrowing of the pyloric opening of the stomach that results from hypertrophy of the circular layer of smooth muscle in that region. Infants with this congenital anomaly violently vomit the contents of a meal several hours after eating.

Specify the spinal cord segments that supply preganglionic sympathetic fibers to midgut components of the GI system and relate this to referred pain patterns from these organs.

Receive preganglionic signals from the T10-T12 levels. Visceral pain from these organs is referred to the corresponding dermatomes of the body wall.

Specify the spinal cord segments that supply preganglionic sympathetic fibers to hindgut components of the GI system and relate this to referred pain patterns from these organs.

Receive preganglionic signals from the T12-L2/L3 levels. Visceral pain from these organs is referred to the corresponding dermatomes of the body wall.

Specify the spinal cord segments that supply preganglionic sympathetic fibers to foregut components of the GI system and relate this to referred pain patterns from these organs.

Receive preganglionic signals from the T5-T9/T10 levels. Visceral pain from these organs, as well as that of the spleen, is referred to the corresponding dermatomes of the body wall.

Compare internal and external hemorrhoids in terms of location and the veins involved; compare the signs & symptoms of the different types of hemorrhoids and specify the risk factors that lead to their development. RISK FACTORS

Risk Factors - Portal Hypertension, Pregnancy, Chronic Constipation, Straining during defecation, and Venous return disorders

Describe the developmental basis of the following normal features of the GI tract: lesser sac of the peritoneal cavity

Rotation of the stomach and fusion of the duodenum to the posterior abdominal wall create a small alcove posterior to the stomach and adjacent structures. This alcove is the lesser sac of the peritoneal cavity.

Describe how abdominal aponeuroses relate to one another in the semilunar line.

Semilunar line is a line that divides the three muscles from their aponeuroses. On a person, we see this line as where we can see our "obliques".

Distinguish visceral pain from somatic pain in terms of intensity and ability to localize; define referred pain.

Somatic Pain: Well localized. Sharp, burning, or even dull ache. Visceral Pain: Poorly localized. Aching, pressure, dull. Referred Pain - Pain felt in a site/location that is distant from the actual location of the stimulus. Referred pain can mimic both somatic and visceral pain symptoms

Specify the structures of the abdominopelvic GI system supplied by specific branches of the celiac trunk

Splenic Artery: o Stomach o Spleen Common Hepatic Artery: o Liver o Pancreas o Stomach o Proximal Duodenum Left Gastric Artery: o Stomach o Esophagus Proper Hepatic Artery (Branch of Common Hepatic Artery): - Liver - Gallbladder Gastroduodenal Artery (Branch of Common Hepatic Artery): - Stomach - Proximal Duodenum

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: celiac plexus

Subdivision of the Pre-Aortic Plexus that contains the Celiac, Aorticorenal, and Superior Mesenteric Ganglia. Provides postganglionic sympathetic neurons for the Thoracic Splanchnic Nerves and structures of the Foregut and Midgut.

Relate the following structures to the pathways of sympathetic and parasympathetic innervation to viscera located in the abdomen and pelvis: aortic plexus

Subdivision of the Pre-Aortic Plexus that contains the Inferior Mesenteric Ganglia. Provides postganglionic sympathetic neurons for the Lumbar Splanchnic Nervesand structures of the Hindgut.

Distinguish the regions of the GI tract that receive parasympathetic innervation from the vagus nerve

Terminal ganglia in the Foregut and Midgut GI viscera (Preganglionicfrom Brainstem).

Distinguish the regions of the GI tract that receive parasympathetic innervation from the pelvic splanchnic nerves

Terminal ganglia in the Hindgut viscera and pelvic viscera.(Preganglionic from S2-S4 spinal levels).

Specify the three veins that coalesce to form the hepatic portal vein.

The Three Veins that form the Hepatic Portal Vein: o Splenic Vein o Superior Mesenteric Vein o Inferior Mesenteric Vein

Specify where in the peripheral nervous system the cell bodies of visceral afferent neurons are located (dom)

The cell bodies of the preganglionic parasympathetic neurons involved in the innervation of abdominopelvic viscera reside in both the brainstem and the S2-S4 segments of the spinal cord. The preganglionic fibers from the brainstem distribute to terminal (intramural) ganglia of abdominal viscera via the vagus nerve and its branches; preganglionic fibers from the S2-S4 spinal cord distribute to terminal ganglia of abdominal and pelvic viscera via pelvic splanchnic nerves and their branches. Visceral pain information, on the other hand, which is often referred to somatic regions of the body, travels retrograde along either sympathetic or parasympathetic pathways. For the abdominopelvic GI viscera, the line of demarcation between sympathetic and parasympathetic visceral pain routes is the midpoint of the sigmoid colon. Visceral pain sensation from abdominal GI viscera located proximal to this "gut tube pain line" travels retrograde along sympathetic routes; visceral pain from the distal half of the sigmoid colon, the rectum and the portion of the superior 2/3 of the anal canal travels retrograde along parasympathetic routes.

Explain the anatomical basis of biliary occlusion leading to pancreatitis and/or jaundice.

The distal end of the Hepatopancreatic Ampulla is the narrowest part of the biliary passages and is a common site for impaction of gallstones. Impaction at this location, or anywhere along the Common Bile Duct, results in obstruction of bile flow from the Liver and obstructive Jaundice. If the obstruction is in the Ampulla, it often also leads to Pancreatitis.

List the structures bordering, and their relationship to, the omental (epiploic) foramen.

The epiploic foramen is created by the free edge in the lesser omentum. It is below the liver, to the right of the gall bladder, and above the jejunum. Recall that the epiploic foramen is the site of communication between the greater and lesser sacs of the peritoneal cavity and that the portal triad (portal vein, bile duct and proper hepatic artery) are located in the hepatoduodenal ligament that forms its anterior boundary. Lying posterior to the epiploic foramen, in the retroperitoneal space, is the inferior vena cava

Describe the boundaries and contents of the ischioanal fossae and their continuity with the deep perineal pouch. from dude

The ischioanal fossae are: -Lateral border are the obturator internus and ischium -Posterior border is the gluteus maximus and sacrotuberous ligament -Medial border is the anal canal and anal sphincter -Anterior border is the inferior pubis It contains mostly fat -Clinical: ischioanal fossa abscesses are painful and indicated by fullness and tenderness. Located between the anus and ischial tuberosity

Describe the developmental basis of the following normal features of the GI tract: greater omentum.

The lesser sac enlarges as a result of progressive expansion of the dorsal mesentery (dorsal mesogastrium) connecting the stomach to the posterior body wall. The resulting large, suspended fold of mesentery, the greater omentum, hangs from the dorsal body wall and the greater curvature of the stomach and drapes over more inferior organs of the abdominal cavity.

Describe how abdominal aponeuroses relate to one another in the linea alba

The linea alba is a line where formed by the combination of the aponeuroses of all three muscles from both sides (since these muscles DO NOT cross to the other side, their aponeuroses just meet at the middle and form this)

List the structures derived from the midgut region of the embryonic gut tube.

o Distal Duodenum o Jejunum o Ileum o Cecum o Appendix o Ascending Colon o Proximal 2/3rds of Transverse Colon

Describe the relationship of the superior mesenteric vessels to the pancreas.

The neck of the pancreas is located directly anterior to the superior mesenteric artery and superior mesenteric vein. The numerous branches of the superior mesenteric artery supply blood to the pancreas. Additionally, branches of the celiac circulation anastomose with branches of the superior mesenteric artery in the substance of the pancreas.

Define the retroperitoneal space.

The organ-filled space located posterior to the peritoneal sac and anterior to the posterior body wall is termed the retroperitoneal space. contains: - kidneys - ureters - adrenal glands - abdominal aorta - inferior vena cava - some organs of the gastrointestinal system.

Explain the significance of the pectinate line in terms of blood supply and drainage, lymphatic drainage, and innervation of the anal canal.

The pectinate line is a landmark to show where arteries, veins, nerves, and lymphatics of the anal canal are. Specifically, it divides the upper visceral portion from the lower somatic portion Visceral portion contains: Mixed sympathetic and parasympathetic innervation Inferior mesenteric artery Veins going to the portal venous system Internal iliac lymph nodes Somatic portion contains: Somatic motor and sensory innervation Internal iliac artery Caval venous system Superficial inguinal lymph nodes a. The pectinate line is the demarcation between the visceral portion of the anal canal and the somatic portion of the anal canal. b. Inferior to the pectinate line the anal canal is innervated by branches of the pudendal nerve (formed from contributions from the S2, S3 and S4 ventral primary rami) and is therefore sensitive to pain, touch, and temperature. The anal canal inferior to the pectinate line is supplied by the internal iliac artery, specifically the inferior rectal branch of the internal pudendal artery). Lymph from interstitial tissue located inferior to the pectinate line flows to the superficial inguinal lymph nodes (as does lymph from the remainder of the perineum) and ultimately to the lumbar lymphatic trunks via lymphatic vessels paralleling the course of the external and common iliac vessels. Venous blood drained from the distal 1/3 of the anal canal is conveyed directly to the caval system via tributaries to the internal iliac venous network

Specify the spinal cord segments to which visceral pain sensation traveling along sympathetic and parasympathetic pathways is transmitted. (CHECK THIS ONE)

The spinal cord segments to which visceral sensations is transmitted are T1-L2 (3) and S2-S4. The cell bodies of visceral afferent neurons are located in the Dorsal Root Ganglions.

Describe the relationship of the spleen to the rib cage and diaphragm.

The spleen lies deep to the ribs 9-12 on the left side; it is separated from the left costodiaphragmatic recess by the left dome of the diaphragm.

List the planes used to divide the abdomen into four (4) quadrants and specify the names of each; be able to recognize these quadrants in images and descriptions of the abdominal wall.

Transumbilical plane and sagittal plane (median plane) divide the abdomen into the LUQ, LLQ, RUQ, and RLQ.

List the planes used to divide the abdomen into nine (9) body regions and specify the name of each region; be able to recognize each region in images and descriptions of the abdominal wall.

Two midclavicular planes, subcostal plane, and intertubercular plane can form 9 body regions in the abdomen. The nine regions are: Left hypochondrium Left flank Left groin Epigastric region Umbilical region Pubic region Right hypochondrium Right flank Right groin

Specify the structures that create the following peritoneal folds: medial umbilical folds, lateral umbilical folds.

Umbilical folds is just fancy for parts of the peritoneum where the artery causes a outline to form since it's running under it (kind of like how our veins make outlines on our skin) Medial umbilical fold: this is formed by the cut-off ends of the umbilical arteries (Formed by the fibrous remnants of the distal aspects of the umbilical arteries) Lateral umbilical fold: this is formed by the inferior epigastric (right and left) arteries

Describe the changing pattern of pain typical of an advancing case of appendicitis and specify which pain is visceral and which pain is somatic in origin.

Visceral pain associated with the onset of appendicitis will refer to the umbilical region of the anterior abdominal wall. As the infection progresses the increasingly inflamed appendix, depending upon its position, may come into direct contact with and irritate the parietal peritoneum of the anterior abdominal wall, resulting in sharp somatic pain at McBurney's point.

Specify the lymph pathways and the lymph node groups involved in the spread of pathology from foregut, midgut and hindgut viscera

a. At the base of each of the three unpaired branches of the abdominal aorta is a collection of lymph nodes (celiac nodes, superior mesenteric nodes, inferior mesenteric nodes). These lymph nodes screen and filter the lymph collected from tissues along that specific artery's distribution route. Once filtered, the lymph collected from the various regions of the GI tract drains to intestinal lymphatic trunks (trunks = large lymphatic vessels). b. Only some of the lymph collected from the rectum drains via inferior mesenteric lymphatic routes and inferior mesenteric lymph nodes. The remainder of the lymph from the rectum, and lymph from the hindgut-derived portion of the anal canal as well, drains to lymphatic vessels and lymph nodes located along the courses of the internal iliac and common iliac vessels. These lymphatic vessels drain superiorly via lymphatic vessels on either side of the abdominal aorta and eventually coalesce into large lumbar trunks just inferior to the aortic hiatus (Gray's Fig. 4.168; see below). In addition to conveying lymph from the rectum and anal canal, the iliac and para-aortic lymphatic vessels and lumbar trunks convey lymph from the lower limbs, peritoneum, retroperitoneal space, and deep body wall. c. Inferior to the aortic hiatus the intestinal lymphatic trunks coalesce with lumbar lymphatic trunks to form the cisterna chyli. Lymph within the cisternal chyli drains via the thoracic duct to the left venous angle.

Describe the boundaries and contents of the ischioanal fossae and their continuity with the deep perineal pouch. from Dom

a. Boundaries of the ischioanal fossae: i. lateral boundary: ischium and obturator internus muscle covered with obturator fascia. ii. medial boundary: anal canal and external anal sphincter. iii. posterior boundary: sacrotuberous ligament and gluteus maximus muscle. iv. anterior boundary: inferior aspect of pubis - note that this portion of the ischioanal fossa is located superior to the perineal membrane - a transversely-oriented sheet of connective tissue that anchors the erectile bodies of the external genitalia. b. Upon entering the ischioanal fossa the pudendal nerve and internal pudendal artery course anteriorly along the internal surface of the obturator internus muscle towards the urogenital triangle of the perineum housing the external genitalia and urethra. Within the ischioanal fossa the pudendal nerve and internal pudendal artery give rise to the inferior rectal nerve and artery, respectively, which innervate and supply structures of the anal triangle, including the external anal sphincter

Relate sympathetic and parasympathetic motor pathways to the transmission of visceral sensation to the central nervous system (CNS); distinguish the types of visceral sensation that typically travel along sympathetic vs parasympathetic routes. (Dom)

a. The cell bodies of visceral afferent neurons are located in dorsal root ganglia along with those of somatic afferent neurons. From here the visceral afferent cells each send a "central process" into the spinal cord to synapse on cells of the dorsal horn. The "peripheral processes" of the visceral afferent neurons reach receptors in the body cavity viscera by traveling with autonomic (sympathetic and parasympathetic) nerves. Visceral sensation therefore travels retrograde along sympathetic and parasympathetic pathways to reach the CNS. b. With respect to visceral pain pathways, the general rule is that visceral pain fibers travel along sympathetic pathways to reach the CNS (visceral reflex fibers, on the other hand, travel along parasympathetic routes). A significant exception to this rule concerns the pelvic viscera. Pain from the inferior most portions of these viscera (portions inferior to the peritoneum) travel retrograde along parasympathetic nerves to reach the CNS (sacral region of the spinal cord).

Describe the relationship of the gallbladder to the rib cage, diaphragm, and liver; describe the changing pattern of pain associated with cholecystitis.

a. The gallbladder sits within the gallbladder fossa on the visceral surface of the liver. (underside) b. In the erect patient the fundus of the gallbladder(the blunt surface opposite its opening at the cystic duct) is located approximately at the junction of the 9th costal cartilage with the lateral border of the rectus abdominis muscle (semilunar line). In the supine VHD model the fundus is located slightly higher, at the junction of the 7th costal cartilage with the semilunar line (it may be necessary to highlight the gallbladder to see this relationship). Internally the fundus is separated from the ribs and costal cartilages by the right dome of the diaphragm. c. Obstruction of the cystic duct by a gallstone causes enlargement and inflammation of the gallbladder, a condition termed "cholecystitis". The dull visceral pain associated with this condition in its early stages is felt in the epigastric region (see Surface Topography of the Abdomen, below). With further development the pain intensifies as presents as sudden sharp pain in the right hypochondriac region that spreads to the right shoulder and back.

Describe the relationship of the liver to the rib cage, diaphragm, and other foregut organs; specify where a liver biopsy should be taken so as to avoid injury to related structures.

a. The liver lies deep to ribs 7-11 on the right side and crosses the midline towards the left nipple; it is separated from the pleura, lungs, pericardium and heart by the diaphragm. b. The superior and (some of the) posterior surfaces of the liver are in contact with the thoracic diaphragm. c. Lies superior to the stomach, gallbladder, right kidney, and intestines. d. Needle biopsies of liver tissue are collected by inserting the needle into the 10th intercostal space. In these procedures the patient is directed to hold their breath in full expiration so as to reduce the costodiaphragmatic recess and reduce the likelihood of contaminating the pleural cavity or damaging the lung.

Specify the muscular components of the walls of the true pelvis and relate these to the pelvic diaphragm; explain the significance of the tendinous arch of the levator ani/obturator internus.

ic cavity's wall are made up of two muscles: o Piriformis (posterolateral wall) o Obturator internus (lateral wall) The pelvic diaphragm is made up of two muscles as well: o Levator ani (front portion) o Coccygeus (back portion) - The tendinous arch is a specialized fascia that the levator/ani attaches to. - It is at the medial border of the obturator internus and looks like a white tendon, similar to central tendon in appearance - In other words, the borders of the obturator internus and levator ani meet at the tendinous arch

Describe the function of the pelvic diaphragm.

suspended from attachments in the interior of the articulated pelvis and is somewhat funnel-shaped in appearance pelvic diaphragm provides the major support for the pelvic viscera and resists increases in intra-abdominal pressure that occur during forced expiration, coughing, vomiting, sneezing, urinating, defecating and lifting heavy objects which requires trunk fixation. Weaknesses of the pelvic diaphragm can lead to prolapse of pelvic organs and urinary and/or fecal incontinence.