Where are the cell bodies of visceral afferent nerve fibers?
Dorsal root ganglion concentrated at three sites: Celiac, Superior mesenteric, Inferior mesenteric
Are visceral afferents part of the autonomic nervous system?
What region of the gut does each of the three concentrated regions supply? What do these regions of the gut include specifically?
Celiac A.: Foregut (distal esophagus, stomach, duodenum, biliary and pancreas refers pain to T6-8); Superior Mesenteric A.: Midgut (small bowel, appendix, prox. colon refers pain to periumbilical region T9-10); Inferior Mesenteric A.: Hindgut (distal colon, rectum refers pain to hypogastric T11-L1)
What are the three mechanisms of pain? What is there no response to?
1.distention; 2.ischemia; 3.mesenteric traction; No response to thermal, tactile, or chemical stimulation
What is peritonitis a result of?
Thermal, tactile, or chemical irritation
What are the abdominal dermatomes? What level is the central diaphragm?
T6-L1; Diaphragm at C3,4,5
What is Kehr's sign? What is the mechanism for this? What does Kehr's sign on the left usually mean?
Pain in the tip of the shoulder as a result of blood or other irritants in the peritoneal cavity. This is known as referred pain. Irritation of the diaphragm is signalled by the phrenic nerve to the shoulder. Kehr's sign in the left shoulder is a classic sign of ruptured spleen.
What makes up the portal triad?
portal vein, hepatic artery and common bile duct
Define Ascites. Give examples of it.
Occurs when production of peritoneal fluid exceeds absorption. Examples: Cirrhosis, Chornic renal failure, nephrotic syndrome
Foramen of Winslow
Site of entrance into the lesser sac. Through the omental foramen into the omental bursa.
Compression of the hepatoduodenal ligament occludes both hepatic artery and portal vein, limiting all blood flow into the liver
Where does free fluid in the peritoneal cavity flow to?
Most dependent region of the peritoneum (the pelvis)
What nerves innervate the parietal and visceral peritoneum?
Parietal: innervated by somatic sensory nerves; Visceral: sensory nerves which follow sympathetic innervation of the organ
What nerves convey symp and parasymp tone to the esophagus? What are the results?
What is the arterial blood supply and venous drainage of the intrathoracic esophagus and the distal esophagus/gastroesophageal junction?
Netter's page 231-232
What is the lymphatic drainage of the intrathoracic and distal esophagus?
Netter's page 233
What does enlargement of nodes in patients with esophageal malignancies suspect?
What prevents reflux of stomach acid into the esophagus? Is it a sphincter? What happens if reflux does occur?
NO anatomical sphincter present. Reflux is prevented by a region of high pressure due to smooth muscle contraction. Acid in esophagus can cause irritation to squamous esophageal mucosa.
What is the blood supply of the stomach or the 5 groups of arteries off the celiac trunk?
All branches of celiac trunk. 1. Left gastric A, 2. Right gastric A. (branch of hepatic A), 3. Right gastro-omental A. (branch of gastroduodenal A.), 4. Left gastroomental A. (branch of splenic A.), 5. Short gastric A. (branch of splenic A.)
What are some common gastric pathologies and their causes?
Erosive gastritis: NSAIDs or Alcohol, Ulceration: secondary to helicobacter pylori, Carcinoma
What nerves convey symp and parasymp tone to the stomach? What are the results?
Symp: celiac ganglion and plexus (greater splanchnic nerve T6)--> inhibits smooth m. contraction and vasoconstricts arteries.; Parasymp: vagus nerve ---> stimulates peristalsis and acid secretion