GI tract Flashcards
What is the digestive system also known as?
Alimentary tract
List the components of the digestive system.
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small intestine (duodenum, jejunum, ileum)
- Large intestine (cecum, ascending colon, transverse colon, descending colon, rectum)
Which glands are associated with the digestive system?
- Salivary glands
- Liver
- Pancreas
What is the role of digestive juices?
What structure connects the pharynx to the stomach?
Esophagus
What is located at the lower end of the esophagus?
Circular muscle or sphincter at cardiac orifice
What are the three parts of the stomach?
- Fundus
- Body
- Pylorus
Describe the shape of the stomach.
J shaped
How many openings does the stomach have and what are they?
- 2 openings: cardiac orifice, pyloric orifice
What are the two curvatures of the stomach?
- Lesser curvature
- Greater curvature
What are the folds in the stomach called?
Rugae
How long is the small intestine?
23 feet long
What is the width of the small intestine?
1 inch wide
What is the normal thickness of the small intestine wall if the stomach is not distended?
2-6 mm thick
What is the thickness of the bowel wall if the stomach diameter is greater than or equal to 8 cm?
2-4 mm thick
Where does the duodenum begin?
At the pylorus
What is the orientation of the first part of the duodenum?
Transversely oriented
What structures are located posterior to the second part of the duodenum?
- CBD
- GDA
What is the location of the Ampulla of Vater?
Midway where CBD and pancreatic duct pierce wall
Describe the orientation of the third part of the duodenum.
Longitudinally oriented
What is the position of the third part of the duodenum in relation to the SMA and aorta?
Located between SMA and aorta
How does the fourth part of the duodenum ascend?
Superiorly to the left then runs forward at duodenojejunal junction
Where does the fourth part of the duodenum terminate?
At the jejunum
What is the length of the jejunum before it becomes ileum?
2 m
What are the folds in the inner wall of the jejunum called?
villi
What does the ileum enter?
large intestine
What are the segments of the large intestine called?
haustra
Which structure has no haustra?
appendix
Where is the hepatic flexure located?
right upper quadrant (RUQ)
Where is the splenic flexure located?
left upper quadrant (LUQ)
What is the length of the rectum?
12 cm
What is the ‘bull’s eye sign’ associated with?
colon
What is the vermiform appendix a remnant of?
the apex of the cecum
Describe the location of the appendix.
It may lie superiorly behind the cecum, medially behind the ileum and mesentery, or downward and medial into the true pelvis
Where is the appendix located?
Located on the abdominal wall under McBurney’s point
What are the main functions of the liver in digestion?
Processes and stores nutrients
What does the stomach do to food?
Contracts and mixes food
What is the process that moves food through the digestive tract?
Peristalsis
What is food converted into after 3-4 hours in the stomach?
chyme
What substances are involved in the digestion and movement of food?
mucus, hydrochloric acid, and enzymes
What happens to nutrient molecules in the intestine?
They pass through the wall into the blood or lymph system by absorption
What hormone is released by the presence of fat in the intestine?
Cholecystokinin
What does cholecystokinin regulate?
Gallbladder contraction and gastric emptying
What is the role of secretin in digestion?
Stimulates the secretion of bicarbonate to decrease the acid content of the intestine
What is the most common laboratory datum indicating gastrointestinal issues?
Blood in the stool (hematochezia).
What condition may result from chronic blood loss?
Anemia may be present.
What laboratory finding indicates infection in gastrointestinal problems?
Elevation of the white blood count (WBC).
What does an increase in carcinoembryonic antigen (CEA) indicate?
It is found in patients with inflammatory bowel disease or colon cancer.
What are common clinical signs and symptoms of gastrointestinal problems?
Nausea, vomiting, diarrhea, abdominal pain, and fever.
What imaging techniques are used for sonographic evaluation of gastrointestinal issues?
Endoscopy, colonoscopy, CT, MRI, UGI, LGI (BE).
What is the pseudokidney sign?
It indicates inflamed bowel.
What are the five layers of the bowel wall?
Mucosa, submucosa, muscularis, serosa, mesothelium.
Which bowel wall layers are echogenic?
The odd-numbered layers (first, third, fifth).
What is the average total thickness of the bowel wall when distended?
3 mm (if distended) or 5 mm (if undistended).
What is the clinical significance of hypertrophied pyloric stenosis?
More predominant in males, 2-6 weeks old, causes projectile vomiting and dehydration.
What is the defining measurement for hypertrophied pyloric stenosis?
Channel length > 18 mm, muscle thickness > 4 mm, pyloric cross-section > 15 mm.
What is Crohn’s disease?
A recurrent granulomatous inflammatory disease of the colon.
What are the two types of intestinal obstructions?
Mechanical and nonmechanical (paralytic ileus).
What is Meckel’s diverticulum?
A congenital sac or blind pouch found in the lower ileum.
What causes acute appendicitis?
Luminal obstruction and inflammation leading to ischemia of the vermiform appendix.
What are the symptoms of acute appendicitis?
Periumbilical pain, rebound tenderness, nausea/vomiting, anorexia, diarrhea, leukocytosis, and fever.
What is the maximal diameter of a normal appendix?
Maximal diameter in normal appendix ≤ 6 mm.
What indicates an inflamed appendix on ultrasound?
Appendix > 6 mm diameter and wall thickness > 2 mm.
What is the target-shaped appearance in appendicitis?
Hyperechoic inner ring & outer hypoechoic ring.
What is the rate of perforation in preschool children with appendicitis?
Can be as high as 70%.
What are some differential diagnoses for appendicitis?
Acute gastroenteritis, mesenteric lymphadenitis, ruptured ectopic pregnancy, and more.
What is acute intestinal pseudoobstruction (ileus)?
Characterized by failure of the intestine to propel its contents leading to reduced motility.
What is the sonographic finding in ileus?
Distended small bowel (air or fluid).
What is intussusception?
Telescoping of bowel: segment of bowel prolapses into a more distal segment
Most common obstructive bowel disorder of early childhood
What are the clinical findings of intussusception?
- Crampy intermittent abdominal pain
- Vomiting
- Passage of blood through rectum
What are the sonographic findings of intussusception?
- Oval, pseudokidney mass with central echoes in sagittal imaging
- Sonolucent doughnut or target configuration in trans
- ‘Cinnamon bun’ sign
What type of cancer is the most common tumor of the GI tract in children under 10?
Lymphoma
Occurs usually in patients 65 years old and causes multiple nodules, 10-20% in GI tract
What are common symptoms of adenocarcinomas in the GI tract?
- Weight loss
- Pain
- Anorexia
- Vomiting
- Large, bulky mass
What is ascaris?
Type of round worm ingested by humans that resides in GI tract and lungs
What are the sonographic findings of ascariasis?
- Bowel wall thickening
- Identification of tangles of worms in GI tract, aka: ascaris balls
What are bezoars?
Intraluminal masses of undigested material
What are the types of bezoars?
- Trichobezoar (hairball)
- Phytobezoar (undigestible plant or vegetable materials)
- Lactobezoar (milk materials, seen in infants)
- Concretions (inorganic substances, medications, gum)
What is trichobezoar?
Hairball associated with Rapunzel syndrome, having a long tail extending from stomach to small intestine
What symptoms are associated with gastric ulcers?
Intermittent epigastric pain 2-3 hours after eating
What can be seen if a gastric ulcer perforates?
Fluid and air bubbles
What is the nature of polyps in the GI tract?
Typically benign but have the ability to become malignant
