Gray's Anatomy Chapter 64 - Small Intestine

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Questions and Answers

Damage to what artery is most likely if a peptic ulcer erodes the posterior wall of the superior part of the duodenum?

  • Common hepatic artery
  • Superior mesenteric artery
  • Right gastric artery
  • Gastroduodenal artery (correct)

Which anatomical structure is NOT located anterior to the descending part of the duodenum?

  • Gallbladder
  • Right kidney (correct)
  • Right lobe of the liver
  • Transverse colon

What is the clinical significance of the suspensory ligament of the duodenum (ligament of Treitz)?

  • A landmark for identifying the duodenojejunal flexure (correct)
  • Preventing kinking or twisting of the jejunum
  • Controlling the rate of gastric emptying into the duodenum
  • Regulating blood flow to the small intestine

The horizontal part of the duodenum passes anterior to which of the following structures?

<p>Right gonadal vessels (C)</p> Signup and view all the answers

What is a common site for diverticula to occur in the small intestine?

<p>Duodenum, specifically the medial wall of the descending part (B)</p> Signup and view all the answers

What is the Kocher manoeuvre used to primarily expose?

<p>Retroperitoneal structures, such as the inferior vena cava and head of the pancreas (A)</p> Signup and view all the answers

What determines the location of the duodenojejunal junction?

<p>Length and characteristics of the suspensory ligament of the duodenum (C)</p> Signup and view all the answers

What anatomical feature primarily characterizes the internal appearance of the descending part of the duodenum?

<p>Pronounced circular mucosal folds (D)</p> Signup and view all the answers

What supplies arterial blood to the ascending part of the duodenum?

<p>Both the coeliac trunk and superior mesenteric artery (B)</p> Signup and view all the answers

What is the primary lymphatic drainage pathway from duodenum?

<p>To nodes associated with pancreaticoduodenal arteries, and then the common hepatic and superior mesenteric arteries (B)</p> Signup and view all the answers

Which of the following accurately describes the venous drainage of the duodenum?

<p>It drains into the superior mesenteric vein and the portal vein. (B)</p> Signup and view all the answers

What alteration is seen in the small intestine following surgical resection and adaptation?

<p>Increase in diameter, villous height and intestinal gland depth (B)</p> Signup and view all the answers

What are the features that are most suggestive of the diagnosis congenital ileal diverticulum?

<p>Located on the mesenteric border and contains adipose tissue containing the omphalomesenteric artery (D)</p> Signup and view all the answers

How does the sympathetic nervous system affect the duodenum?

<p>Vasoconstriction and inhibits muscle contraction (D)</p> Signup and view all the answers

In which anatomical structures does the anterior superior pancreaticoduodenal artery travel?

<p>Between the descending duodenum and the head of the pancreas (D)</p> Signup and view all the answers

There is a higher output with greater electrolyte loss in case of a proximal small intestine surgical intervention compared to distal small intestine, why is that the case?

<p>Proximal small intestine can only absorb sodium across a small sodium gradient while distal small intestine can absorb through a large gradient (A)</p> Signup and view all the answers

How does the arterial arrangement for the small intestine impact outcomes from dilation or other vascular incidents?

<p>There can be a longitudinal splitting creating longer lengths, the segment can be tubularized by length; aids in vascular events (D)</p> Signup and view all the answers

There is smooth muscle throughout each villus; what is the implication of this anatomy?

<p>Allows villus contraction to provide content to the lymphatic plexus (A)</p> Signup and view all the answers

What is the role of the M cells?

<p>Antigen endocytosis and transportation to lymphocytes (A)</p> Signup and view all the answers

Stem cells in the intestinal glands are exposed to specific molecules; what happens if the intestinal glands are injured or destroyed?

<p>Stem cell daughter cells can retain capacity and revert back (B)</p> Signup and view all the answers

Following the division of the peritoneum, you retract to the right what anatomical structure can you visualize?

<p>Aorta (D)</p> Signup and view all the answers

What type of abdominal operation can benefit from reinnervation of the vessel for full function?

<p>Bowel Transplant (D)</p> Signup and view all the answers

An individual is found to have 258 intestinal folicles in their lymphoid patches. You can recognize that that individual is likely

<p>Early childhood (B)</p> Signup and view all the answers

Which cellular structure connects ICCs with each other and nearby smooth cells for better electrical conduction signals?

<p>Gap junctions (C)</p> Signup and view all the answers

What cellular structure has the highest number in individuals in the terminal ileum?

<p>Goblets (C)</p> Signup and view all the answers

Where are the Brunner glands?

<p>Duodenum (D)</p> Signup and view all the answers

Of the following choices, what is unique with patients that retain a section of continuity containing the ileum, in comparison to patients that retain a segment limited to only a duodenojejunal. Why?

<p>Higher Likelihood of gaining interventional and intestinal autonomy (B)</p> Signup and view all the answers

The internal anal sphincter has a different make-up, what is that?

<p>Smooth Muscle Innervated (D)</p> Signup and view all the answers

What is one symptom experienced from an intestinal obstruction?

<p>Distribution of Vessels (B)</p> Signup and view all the answers

Duodenal bulb is a result of what?

<p>Insufflation Endoscopy (B)</p> Signup and view all the answers

How often does a typical Intestinal Epithelium get reproduced?

<p>Every few days (C)</p> Signup and view all the answers

Pancreaticduodenectomy operation are exposed by

<p>Kocher maneuver (D)</p> Signup and view all the answers

Where do vessels enter when reaching the intestinal wall? (select nearest to where they enter)

<p>Mesenteric Border (B)</p> Signup and view all the answers

What type of disease is less commonly found in individuals with malrotation because of their potential?

<p>Vessel Collateral (B)</p> Signup and view all the answers

What is the approximate length of the adult duodenum?

<p>25 cm (A)</p> Signup and view all the answers

Which anatomical structure is covered by peritoneum only on its proximal anterior surface?

<p>Descending part of the duodenum (D)</p> Signup and view all the answers

What structural characteristic differentiates the duodenal bulb from the rest of the duodenum's internal appearance?

<p>Relatively smooth mucosa (A)</p> Signup and view all the answers

Based on anatomical location, which part of the duodenum is at greatest risk of iatrogenic injury during surgical mobilization of the ascending colon and right colic flexure?

<p>Descending part (C)</p> Signup and view all the answers

What anatomical relationship is present between the horizontal part of the duodenum and the superior mesenteric artery?

<p>The horizontal part lies posterior to the superior mesenteric artery (B)</p> Signup and view all the answers

Which statement accurately describes the suspensory ligament of the duodenum?

<p>It suspends the duodenojejunal flexure from the anterior wall of the retroperitoneum. (C)</p> Signup and view all the answers

What anatomical anomaly is implicated when the angle between the superior mesenteric artery and the abdominal aorta narrows enough to cause duodenal obstruction?

<p>Superior mesenteric artery syndrome (C)</p> Signup and view all the answers

A surgeon performing a Kocher maneuver to expose the posterior aspect of the pancreatic head would most likely need to divide which of the following?

<p>Posterior and lateral attachments of the descending duodenum (A)</p> Signup and view all the answers

If a patient has their jejunum surgically brought to the surface of the abdomen, what is one distinctive characteristic that can result from this type of stoma?

<p>Relatively high nutrient losses (D)</p> Signup and view all the answers

What action would be most suitable following the Roux-en-Y procedure if they are continuing to suffer from duodenal reflux into the stomach?

<p>Distal end of the feeding tube beyond the duodenojejunal flexure (A)</p> Signup and view all the answers

During a surgical exploration, an omphalomesenteric artery is discovered still present; what additional finding is most commonly expected?

<p>Meckel's diverticulum (B)</p> Signup and view all the answers

What is the approximate duodenal length requirement for qualifying to have Short Bowel Syndrome?

<p>100 cm (A)</p> Signup and view all the answers

In a patient following surgical bowel resection, which intestinal configuration is most likely to result in a greater chance of regaining intestinal autonomy?

<p>Retained ileum segment (A)</p> Signup and view all the answers

What histological changes are observed in the remaining small intestine as a result of the intestinal adaptation process after surgical resection?

<p>Increased intestinal gland depth (D)</p> Signup and view all the answers

Which anatomical structure descends posterior to the superior mesenteric vein?

<p>The inferior pancreaticoduodenal artery (B)</p> Signup and view all the answers

Which of following findings are correlated with the diagnosis if Intestinal Failure?

<p>Micronutrient deficiency (D)</p> Signup and view all the answers

In the context of arterial supply to the duodenum, what is the implication if there exists a common trunk from which the coeliac and superior mesenteric arteries arise?

<p>Increased incidence of duodenal ischemia (A)</p> Signup and view all the answers

What is the clinical significance of the fact that the human duodenum curves in both the anteroposterior direction and as a 'C' shape?

<p>The pancreatic head fits neatly into its concavity. (A)</p> Signup and view all the answers

During a small bowel resection, what is the significance of the diameter size in the jejunum?

<p>Can affect with anastomosis (D)</p> Signup and view all the answers

What is a unique finding to be aware of while operating involving the blood supply and the small intestine?

<p>They do not have direct anastomosis (D)</p> Signup and view all the answers

What anatomical feature is found in the inner intestinal wall that enables better structural support in the ileum compared to the jejunum?

<p>More vascular arcades (D)</p> Signup and view all the answers

How does the small intestine deal with the digestion of dietary fats across their membrane?

<p>Utilize a brush border surface (A)</p> Signup and view all the answers

What property is not a characteric in the function of the small intestine?

<p>Waste storage (B)</p> Signup and view all the answers

What property is responsible for increasing the absorptive properties in the intestinal wall?

<p>Brush order volume size (C)</p> Signup and view all the answers

In terms of absorption, what is the implication if some has a proximal small intestine versus distal small intestine issue?

<p>More salt and water loss (B)</p> Signup and view all the answers

A patient cannot generate salt across in what situation?

<p>Jejunum due to gradient (D)</p> Signup and view all the answers

What mechanism accounts for small intestinal motility in the period between meals?

<p>Migrating motor complex (C)</p> Signup and view all the answers

What physiological change occurs in slow waves along the intestine?

<p>Decreases, so less activity and slow activation (B)</p> Signup and view all the answers

A patient received an intestine transplant; what mechanism is important and required for that transplant to function?

<p>Smooth muscle cells (C)</p> Signup and view all the answers

What causes changes in MMC after sleep?

<p>Phase 2 (A)</p> Signup and view all the answers

During a colon operation, you cut into the area and see a yellow color around; what should happen/what is that?

<p>Micelles for fats, normal so there is more absorption (A)</p> Signup and view all the answers

If a patient is unable to secrete bile acid, what step will not happen?

<p>Distal end cannot absorb properly (A)</p> Signup and view all the answers

In the small intestine, where does MALT reside?

<p>Mostly found in Lamina (C)</p> Signup and view all the answers

Which cells perform the most actions found in the small intestine?

<p>Columnar cells (A)</p> Signup and view all the answers

Which protective measure do you keep in mind while working with the microvilli because of the actions for protection?

<p>Needs mucous and glycocalyx is very important (D)</p> Signup and view all the answers

Following a MALT response and action, what takes place for defense?

<p>Lymphocytes action (A)</p> Signup and view all the answers

What do Paneth cells help with when performing their purpose functionally?

<p>Balance with good and providing the key to being safety (A)</p> Signup and view all the answers

If a patient is experiencing functional intestinal dysmotility due to a defect with the ICC, and can no longer generate the proper pacemaker, what needs to be looked into? ( select the best choice)

<p>Low amounts of channel protein tyrosine (A)</p> Signup and view all the answers

What is the approximate percentage of the circumference of the muscular wall of the ileum that the small intestine mesentery abuts?

<p>20% (D)</p> Signup and view all the answers

Which portion of the duodenum lacks a peritoneal covering on its anterior surface?

<p>Horizontal part (B)</p> Signup and view all the answers

What anatomical feature runs posterior to the horizontal part of the duodenum?

<p>Right kidney (B)</p> Signup and view all the answers

What is the functional implication of the duodenum curving in both anteroposterior direction and also as a C shape?

<p>It positions the duodenum entirely proximal to the umbilicus. (B)</p> Signup and view all the answers

What is the result of losing the perivascular adipose tissue located in the angle between the superior mesenteric artery and the abdominal aorta?

<p>Superior mesenteric artery syndrome (B)</p> Signup and view all the answers

In a surgical operation, what does the Kocher manoeuvre involve?

<p>Division of posterior and lateral attachments of the duodenum to allow medial rotation (B)</p> Signup and view all the answers

If the suspensory ligament of the duodenum is short and narrow, what is the expected trajectory of the ascending part of the duodenum?

<p>A comma-shaped, cephalad trajectory (A)</p> Signup and view all the answers

Which of the following accurately describes the anatomical relationship of the gastroduodenal artery as it relates to the duodenum?

<p>It descends posterior to the retroperitoneal portion of the superior part of the duodenum (A)</p> Signup and view all the answers

Which artery is at risk of erosion due to a penetrating peptic ulcer on the posterior wall of the duodenum?

<p>The gastroduodenal artery. (D)</p> Signup and view all the answers

Why is ischaemia of the duodenum a rare clinical finding?

<p>Due to the robust vascular supply from multiple sources (D)</p> Signup and view all the answers

Which statement accurately describes the arrangement of the superior pancreaticoduodenal arteries?

<p>The posterior is usually a separate branch of the gastroduodenal artery (A)</p> Signup and view all the answers

What is the implication of there not being many connections between the terminal arterial branches close to the intestinal wall?

<p>Segmental ischaemia can be the result when multiple division and occlusion occur. (D)</p> Signup and view all the answers

What are the steps of performing left medial visceral rotation?

<p>Peritoneal reflection and descending division of the colon (D)</p> Signup and view all the answers

During a transverse colon reflection approach, where might a surgeon expose the superior mesenteric artery?

<p>Inferior to the pancreas (C)</p> Signup and view all the answers

What does the remnant of the omphalomesenteric artery give rise to?

<p>It is an embryonic artery, it represents the vitelline artery, giving a small branch. (B)</p> Signup and view all the answers

If the ileum exhibits multiple tiers of vascular arcades, what is the functional implication?

<p>Increased absorptive area (A)</p> Signup and view all the answers

What is the role of myoepithelial cells?

<p>Propagating electrical wave (B)</p> Signup and view all the answers

Where are the aggregated lymphoid nodules most heavily concentrated?

<p>Located in the distal ileum (E)</p> Signup and view all the answers

What occurs if there is damage to the Paneth cells?

<p>Diminished immune and stem cell response (B)</p> Signup and view all the answers

What is the result of damage to the stem cells?

<p>Change the secretion of protein, enzymes and hormones (A)</p> Signup and view all the answers

Which of the following is a key feature of ileal diverticulum?

<p>Associated with fibrous band near umbilicus (B)</p> Signup and view all the answers

In the small intestine, where do the majority of the immune cells reside?

<p>Between the basolateral region (A)</p> Signup and view all the answers

Patients with ileal diverticulum pain are referred to the periumbilical region because

<p>There are both derived from midgut (D)</p> Signup and view all the answers

In the epithelium what is the mechanism for defense for cells to increase secretion against injury and what is its role?

<p>Secrete fluids for lysozymes to reduce microbes and aid immune response (D)</p> Signup and view all the answers

Following small intestine anastomosis; what is unique with patients that retain a segment limited to only a duodenojejunal vs those that retain a portion with the ileum? What outcomes is more likely?

<p>Those with no ileum have a reduced chance of gaining autonomy (B)</p> Signup and view all the answers

What factor is responsible for helping the jejunum provide a wide surface area?

<p>Thick walls (B)</p> Signup and view all the answers

What occurs in between meals in the small intestine?

<p>Cyclical rate of electricity (D)</p> Signup and view all the answers

After absorption, how do dietary fats get through the small intestine?

<p>Converts into chylomicrons for the lymphatic area (A)</p> Signup and view all the answers

The small intestine spans from the stomach's pylorus to the ileocaecal junction, averaging a length of 5 meters in adults.

<p>True (A)</p> Signup and view all the answers

The duodenum extends from the stomach to the ileocaecal valve, marked by the ligament of Treitz.

<p>False (B)</p> Signup and view all the answers

The jejunum and ileum are fixed in the proximal abdomen, separate from the colon loops.

<p>False (B)</p> Signup and view all the answers

In an erect position, jejunum loops can descend anterior to the rectum.

<p>True (A)</p> Signup and view all the answers

The small intestine mesentery abuts about 50% of the muscular wall of the ileum.

<p>False (B)</p> Signup and view all the answers

The adult duodenum measures approximately 45 cm.

<p>False (B)</p> Signup and view all the answers

The duodenum is 'draped' over the prominence formed by the thoracic spine.

<p>False (B)</p> Signup and view all the answers

Only the distal 2.5 cm of the superior part of the duodenum is covered by peritoneum.

<p>False (B)</p> Signup and view all the answers

The lesser omentum is attached to its inferior border and the greater omentum to its superior border.

<p>False (B)</p> Signup and view all the answers

The internal appearance of the duodenal bulb readily constricts on insufflation during endoscopy.

<p>False (B)</p> Signup and view all the answers

The superior part of the duodenum transitions solely at the superior duodenal flexure.

<p>False (B)</p> Signup and view all the answers

The gastroduodenal artery lies immediately anterior to the posterior wall of the duodenum.

<p>False (B)</p> Signup and view all the answers

The descending part of the duodenum extends to the inferior border of the second lumbar vertebral.

<p>False (B)</p> Signup and view all the answers

Part of the head of the pancreas is frequently embedded in the lateral duodenal wall.

<p>False (B)</p> Signup and view all the answers

The bile and pancreatic duct enters the lateral wall.

<p>False (B)</p> Signup and view all the answers

The horizontal part ends at the inferior denal flexure and is approximately 10cm long.

<p>True (A)</p> Signup and view all the answers

The horizontal part is located anterior to the inferior vena cava and abdominal aorta.

<p>True (A)</p> Signup and view all the answers

The ascending part runs superiorly and laterally to the level of the superior border of the fifth lumbar vertebra.

<p>False (B)</p> Signup and view all the answers

The inferior mesenteric vein lies either posterior to the duodenojejunal flexure or at its inferior margin.

<p>False (B)</p> Signup and view all the answers

The duodenum is the least common site for a diverticulum in the small intestine.

<p>False (B)</p> Signup and view all the answers

Match the anatomical description with the corresponding part of the duodenum:

<p>Superior part = Most mobile part, approximately 5 cm long Descending part = Approximately 8 cm long, contains the major duodenal papilla Horizontal part = Approximately 10 cm long, lies posterior to the superior mesenteric vessels Ascending part = 2.5 cm long, transitions into the jejunum at the duodenojejunal flexure</p> Signup and view all the answers

Match the digestive function with the corresponding intestinal structure:

<p>Jejunum = Primary site for nutrient absorption due to numerous plicae circulares and villi Ileum = Absorption of vitamin B12 and bile salts Duodenum = Receives chyme from the stomach and secretions from the pancreas and liver Intestinal glands = Secretion of intestinal juices and enzymes</p> Signup and view all the answers

Match the anatomical relation with the corresponding part of the duodenum:

<p>Superior part = Anterior to the gastroduodenal artery Descending part = Anterior to the hilum of the right kidney Horizontal part = Anterior to the inferior vena cava and abdominal aorta Ascending part = Posterior to the transverse colon</p> Signup and view all the answers

Match the vessel with its tributary:

<p>Superior mesenteric vein = Drains the small intestine, ascending colon, and transverse colon Inferior mesenteric vein = Drains the distal colon and rectum Hepatic portal vein = Formed by the union of the splenic vein and superior mesenteric vein Gastroduodenal artery = Supplies the superior part of the duodenum</p> Signup and view all the answers

Match the vessel with its branch:

<p>Superior mesenteric artery = Supplies the jejunum and ileum Gastroduodenal artery = Supplies the posterior and anterior superior pancreaticoduodenal arteries Ileocolic artery = Supplies the terminal ileum and cecum Right colic artery = Supplies blood to the ascending colon</p> Signup and view all the answers

Match the cell type with its function in the intestinal wall:

<p>Enterocytes = Absorption of nutrients from the intestinal lumen Goblet cells = Secretion of mucus to protect the epithelium Paneth cells = Secretion of antimicrobial substances Stem cells = Replacing of the damaged cells of the intestinal lining</p> Signup and view all the answers

Match the pathology with its common location:

<p>Duodenal ulcers = Often occur in the duodenal bulb Meckel's diverticulum = Usually located in the terminal ileum Diverticula = Commonly occur in the descending duodenum Crohn's disease = Commonly affects the terminal ileum</p> Signup and view all the answers

Match the structural feature with its digestive function:

<p>Villi = Increase surface area for absorption Microvilli = Further increase surface area, forming the brush border Circular folds = Increase surface area and slow the passage of food Lacteals = Absorb fats and transport them to the lymphatic system</p> Signup and view all the answers

Match the surgical procedure and the relevant anatomical structure:

<p>Kocher maneuver = Mobilizes the duodenum to expose the posterior structures, e.g., inferior vena cava Whipple procedure = Involves resection of the head of the pancreas and duodenum Intestinal resection = Removal of a segment of the jejunum or ileum Stoma creation = Creation of an opening between the small instestine and the skin</p> Signup and view all the answers

Match the clinical condition with its description:

<p>Short bowel syndrome = Malabsorption due to significant resection of the small intestine; commonly requires lifelong nutritional support Superior mesenteric artery syndrome = Duodenal obstruction caused by compression between the superior mesenteric artery and the aorta Lactose intolerance = Inability to digest lactose due to deficiency of lactase Ileus = Temporary arrest of intestinal peristalsis; can be caused by operation</p> Signup and view all the answers

Flashcards

Length of the Small Intestine

The small intestine extends from the pylorus to the ileocaecal junction and is approximately 5 meters long.

Jejunum-Ileum Boundary

There is no clear boundary between the jejunum and ileum, but a gradual transition in morphology from the proximal to distal ends of the intestine.

Small Intestine Position

The duodenum is mostly retroperitoneal, while the jejunum and ileum occupy the central and distal parts of the abdominal cavity.

Shape of Duodenum

The duodenum forms an elongated 'C' shape between the first and third lumbar vertebrae.

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Pancreas-Duodenum Position

The head of the pancreas lies within the concavity of the duodenum.

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Superior Duodenum

The superior part is the most mobile part of the duodenum; the proximal 2.5 cm is intraperitoneal, while the distal 2.5 cm is covered by peritoneum on its anterior and superior surfaces. The lesser omentum is attached to its superior border and the greater omentum to its inferior border.

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Duodenum Circular Folds

The internal appearance beyond the duodenal bulb is characterized by circular folds of the mucosa that remain pronounced, even during endoscopic insufflation.

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Superior Duodenum Relations

The superior part of the duodenum lies anterior to the gastroduodenal artery, bile duct and hepatic portal vein and anterosuperior to the head and neck of the pancreas.

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Duodenal Ulcer Risk

A penetrating peptic ulcer on the posterior wall of the duodenum can erode into the gastroduodenal artery or one of its branches and cause dramatic haemorrhage.

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Descending Duodenum

The descending part of the duodenum is covered by peritoneum only on its proximal anterior surface, and lies anterior to the hilum of the right kidney.

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Bile & Pancreatic Ducts

The bile duct and pancreatic duct (of Wirsung) enter the medial wall of the descending duodenum, where they typically unite to form a common channel.

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Duodenum Posterior Relations

The descending duodenum lies anterior to the hilum of the right kidney, the right renal vessels, the lateral edge of the inferior vena cava and right psoas major.

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Horizontal Duodenum

The horizontal part lies posterior to the transverse mesocolon and is crossed anteriorly by the origin of the mesentery of the small intestine and the superior mesenteric vessels.

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Duodenum Relations(Horizontal)

The horizontal part Duodenum lies anterior to the right ureter, right psoas major, right gonadal vessels, inferior vena cava and abdominal aorta.

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Ligament of Treitz

The ascending duodenum is progressively invested in peritoneum such that the duodenojejunal flexure is suspended from the anterior wall of the retroperitoneum by a double fold of peritoneum, the suspensory ligament of the duodenum.

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Duodenum Diverticula

The duodenum is the most common site for a diverticulum in the small intestine. These diverticula are typically located on the medial wall of the descending duodenum.

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What is the Kocher Manoeuvre

Kocher manoeuvre is when the posterior and lateral attachments of the descending portion of the duodenum are divided to allow medial rotation and reflection of the duodenum and head of the pancreas to expose retroperitoneal structures.

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Duodenum Blood Supply

The main vessels supplying the duodenum are the superior and inferior pancreaticoduodenal arteries.

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Gastroduodenal Artery

The gastroduodenal artery usually arises from the common hepatic artery and descends posterior to the retroperitoneal portion of the superior part of the duodenum to the left of the bile duct.

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SMA Origin

The superior mesenteric artery typically has the most acute take-off angle from the major branches of the descending aorta.

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Sympathetic Innervation

Preganglionic sympathetic axons originate from neurones in the interomediolateral grey matter in the fifth to the twelfth thoracic spinal cord segments.

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Jejunum Features

The jejunum has an external diameter of about 4 cm. The circular folds (plicae circulares) are more pronounced in the proximal jejunum

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Jejunum vs. Ileum

In the supine position, the jejunum occupies the proximal left infracolic compartment, and the ileum lies mainly in the hypogastric region and right inguinal region.

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Lymphoid Nodules Distal

Solitary lymphoid nodules are scattered throughout the small intestinal mucosa but are most numerous in the distal ileum. Aggregated lymphoid nodules, Peyer's patches, are not really prominent in the duodenum; typically smaller in the number and impalpable in the distal jejunum.

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Meckel's Diverticulum

Meckel's diverticulum projects from the antimesenteric border of the terminal ileum, between 50-100 cm from the ileocaecal junction.

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Jejunum mesentery vs illeium

The jejunal mesentery, measured from the superior mesenteric artery to the mesenteric border of the intestine, is shorter than the ileal mesentery. The jejunum typically contains 1-3 tiers of vascular arcades whereas there are often 2-6 tiers in the ileum.

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What's an ostomy?

A stoma is a surgically created opening from a hollow viscus to the skin, classified according to its location. An intestinal stoma can be either an end stoma, in a proximal end. or loop stoma, in which both proximal and distal ends of the intestine open

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Short Bowel Syndrome

Short bowel syndrome is a result of surgical resection, congenital deficiency, or disease-associated loss of absorption. The 3 main groups are end-jejunostomy and > 100 small cm, jejunocolic <50cm, jejunoileal <35

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Intestinal Transit is

Three phases of intestinal transit consists of phases: I is quiet; II is irregular, and III is phasic

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Where b12 is at?

Vit B12 is largely absorbed in the terminal ileum after binding to intrinsic factor released by gastric parietal cells.

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Where do lacteas run?

Lacteals are in the submucosa are joined by vessels by lymph vessel

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Terminal Ileum

Distal 30cm of ileum with specialized physiological functions.

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Superior Duodenal Flexure

The superior duodenal flexure lies posterior and inferior to the quadrate lobe of the liver.

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Duodenal Bulb Radiographs

Air can be visible on radiographs of the abdomen as an isolated air shadow to the right of the first or second lumbar vertebra.

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Major Duodenal Papilla

A mucosal elevation on the posteromedial wall of the descending duodenum where the bile and pancreatic ducts enter.

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Hood of the Major Papilla

A duodenal mucosal fold that often partially encircles the major papilla.

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Inferior Mesenteric Vein Location

The duodenojejunal flexure is a useful landmark for locating the inferior mesenteric vein radiologically or surgically.

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Suspensory Ligament Length

Its length determines duodenojejunal junction location.

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Gastroduodenal Artery Divides

An anterior superior pancreaticoduodenal artery and pancreatic branches.

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Posterior Superior Pancreaticoduodenal Artery

It supplies both duodenum and the head of the pancreas.

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Anterior Pancreaticoduodenal Artery

Runs superiorly to anastomose with the anterior superior pancreaticoduodenal artery.

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Pancreaticoduodenal Vein(Superior)

Can drain directly into the hepatic portal vein.

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Duodenum Venous Anastomoses

Numerous anastomoses are present between veins of the descending and horizontal parts of the duodenum and retroperitoneal veins.

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small instestine transplant revovery

There is no extrinsic nerve supply to the graft but intrinsic small intestine motility usually recovers within 48-72 hours after transplantation

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Duodenal Bulb Appearance

The duodenal bulb shows few longitudinal folds and appears triangular; it is often visible on radiographs of the abdomen as an isolated air shadow to the right of the first or second lumbar vertebra.

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Posterior Superior Pancreaticoduodenal Artery

Supplies superior part and proximal descending duodenum.

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Meckel's Diverticulum Connection

Connected to the anterior abdominal wall near the umbilicus by a fibrous band.

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illeum

Has thinner

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Small Intestine

Consists of the duodenum, jejunum, and ileum, connecting the stomach to the ileocecal junction.

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Hepatopancreatic Ampulla

A common channel formed by the union of the bile and pancreatic ducts. It opens on the summit of the major duodenal papilla.

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Jejunum

The ascending part of the duodenum transitions to this at the duodenojejunal flexure; It's suspended from anterior wall by the suspensory ligament.

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Jejunal Artery Branches

Supplies the ascending duodenum and frequently anastomoses with a branch of the anterior superior pancreaticoduodenal artery.

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Duodenal Veins

Duodenal blood is collected in these veins, that drain to the hepatic portal vein, with anastomoses to retroperitoneal veins.

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Duodenum Lymphatics

Ducts running to nodes associated with the pancreaticoduodenal arteries and then to nodes related to the common hepatic and superior mesenteric arteries.

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Kocher Maneuver Purpose

Used to expose the posterior aspect of the head of the pancreas.

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Duodenum Role of Plicae Circulares

Increases absorptive surface area & mixes intestinal contents.

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The anterior pancreaticoduodenal artery connects to

The anterior superior pancreaticoduodenal artery runs down the duodenum to connect. Helps profuse and supply.

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Jejunal branches supplies

They help provide a potential collateral supply to ascending the duodenum

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Where apenndix and diverticulum form

It's derived from the mid-gut.

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Duodenum Mucosa

Covers proximal duodenum, aiding bile and pancreatic secretions in digestion

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Duodenum Submucosa

Supports the mucosa, contains blood vessels and lymphatics

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Duodenum Serosa

Outer layer providing support and protection

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Duodenum Muscularis Externa

Longitudinal and circular layers contracting for peristalsis

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Intestinal Lacteal

A vessel containing milky lymph from fat absorption.

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Peyer's Patches

Aggregations of lymphoid tissue protecting against pathogens.

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Ileum role in bile acid reabsorption

Transports absorbed bile acids back to the liver.

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What do stem cells do?

Stem cells produce all cell types in the Duodenum

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Neuroendocrine Cells in Gut

These secrete signaling molecules to aid in the digestive system

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Where are MALT's?

They are the lymphoid follicles covered

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What does muscularis affect

Muscularis mucosae causes of profiles and aids small intestine

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what are in cajal

These occur around blood vessels and help regulate it's flow

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Serosa surronds what

Peritoneum surrounds what?

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Approaches transverse?

Used to expose superior m.

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Small intestine transplant

Its is a remnant of what?

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Superior (first) part Duodenum

Most mobile part of duodenum, boundary of omental foramen

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Duodenojejunal Flexure

Ileocecal valve and suspensory ligaments secure this point.

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The Duodenum

Connective tissue around the duedenum and trunk.

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Loss of perivascular adipose, tissue

It can lead to superior mesenteric artery syndrome

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Jejunal Feeding Purposes.

Isolate jejunum for internal use to heal others.

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The Kocher Maneuver

Maneuver that requires the pancreas to be identified.

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SMA

Provides blood for everything

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ICC

Transits and helps the enteric.

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Study Notes

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  • The small intestine is 5 metres (3–8.5 metres) long when measured intraoperatively in adults.
  • The jejunum and ileum occupy the central and distal parts of the abdominal cavity within the colon boundary.
  • The small intestine attaches to the anterior retroperitoneum via a mesentery, allowing intestinal loops to be relatively mobile.
  • Loops of jejunum can be anterior to the transverse colon, stomach, and lesser omentum in the supine position.
  • Loops of ileum can descend into the pelvis anterior to the rectum in the erect position.
  • The greater omentum covers the proximal jejunum and ileum to a variable extent.
  • The visceral peritoneum covers the jejunum and ileum except at mesenteric borders.
  • Small intestine mesentery abuts 20% of the muscular wall circumference of the ileum, and less of the jejunum.

Superior Part

  • The superior part of the duodenum has a mean length of 5cm.
  • The duodenum is C shaped between the L1 and L3 vertebrae in the supine position, at the level of the umbilicus.
  • The superior part lies anterior to the gastroduodenal artery, bile duct and hepatic portal vein and anterosuperior to the head and neck of the pancreas.
  • A penetrating peptic ulcer in the posterior wall can erode into the gastroduodenal artery or its branches, causing dramatic haemorrhage.
  • A penetrating peptic ulcer in the anterior wall of the superior part can perforate into the peritoneal cavity, causing peritonitis.
  • Becuase of the anterior surface of the superior part of the duodenum is only covered by peritoneum, this can cause peritonitis
  • Lymph nodes near the common hepatic and hepatoduodenal arteries lie close to the superior part and can be visualized with endoscopic ultrasound.

Descending Part

  • The descending part of the duodenum is approximately 8 cm long, peritoneum covers only its proximal anterior surface.
  • The descending part of the duodenum is covered by peritoneum alone on its proximal anterior surface.
  • The descending part lies anterior to the hilum of the right kidney, the right renal vessels, and the lateral edge of the inferior vena cava and right psoas major.
  • Transverse colon crosses the start of the descending part of the duodenum anteriorly.
  • The right end of the gastrocolic ligament and the origin of the transverse mesocolon attach to the duodenum's anterior surface by loose connective tissue.
  • The head of the pancreas and the bile duct are medial, and the right colic flexure is cephalad and lateral.
  • Surgical mobilization of the ascending colon and right colic flexure poses a risk of iatrogenic injury to the descending part of the duodenum
  • The bile and pancreatic ducts enter the medial wall, forming a common channel which contains the hepatopancreatic ampulla (of Vater).
  • A duodenal mucosal fold sometimes encircles the major papilla, forming a hood, as per Horiguchi and Kamisawa 2010.
  • The accessory pancreatic duct (of Santorini) may be present, opening 2 cm proximal to the major papilla on the minor duodenal papilla, per Kamisawa et al 2010, Suda 2010.

Horizontal Part

  • the Horizontal part of the duodenum is 10cm long
  • the Horizontal part if the duodenum passes to the left slightly superiorly, towards the inferior vena cava and abdominal aorta.
  • Loss of perivascular adipose tissue can cause a rare obstruction, referred to as superior mesenteric artery syndrome, as per Merrett et al, 2009.
  • The peritoneum covers the anterior surface of the left end and horizontal part of the duodenum

Duodenal Diverticula

  • Fotiades et al, 2005, details possible complications of the duodenal diverticula.
  • The Duodenum is the most common site for diverticulum in the small intestine.
  • The diverticula are typically located on the medial wall of the descending part of the duodenum, intimately related to the head of the pancreas.

Ascending Part

  • The ascending (fourth) part of the duodenum is 2.5 cm long.
  • At the lateral limite ascending part gradually invest in the peritonium, resulting in the duodenojejunal flexure that suspends from the anterior wall
  • The suspensory ligament has two parts; the first has skeletal muscle fibers from the right crus of the diaphragm to connective tissue around the coeliac trunk.
  • The second part has smooth muscle descending from connective tissue around the coeliac trunk to the duodenum.

Innervation

  • Bertelli, 1997, provides more information on the description of how to innervate.

Jejunum

  • Typical cross-sections through the proximal jejunum and terminal ileum feature a wider mesenteric attachment in the jejunum, with vascular leaves within the intestinal wall being thicker in the jejunum.

Ileum

  • The ileum primarily lies in the hypogastric region and right inguinal region.

Anatomical differences between the Jejunum and the Ileum

  • Conley et al 2010 provides a refence for the anatomical differences.
  • The straight arteries in the ileum are more numerous, shorter, and narrower than in the jejunum, per Rosenblum et al, 1997.
  • Cornes in 1965 details various observations about aggregated lymphoid nodule size.

Jejunum Surgical Implications

  • If the intestine is open on the surface, volume in the jejunostomy is more than in the ileostomy and may result in loss of more nutrients.
  • The full length of the small intestine from the duodenojejunal flexure to the ileocaecal junction is roughly 5 meters in a male body, but can range.
  • Teitelbaum talks about the small intestine lengths.

Ileum Surgical Implications

  • Meckel's diverticulum is a rare congenital ileal diverticulum that contains ectopic mucosa.

Functionality of the small intestine

  • O'Keefe et al, 2006 states that short bowel syndrome results from surgical resection that results in loss of absorption.

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