1B-Anatomy of the WALL

Question 1

Where are the contents within the lumen of the GI tract technically located?

Answer 1

Outside the Body!

Question 2

What are the three examples of problems from contents from the lumen accidentally getting into the peritoneal cavity?

Answer 2

Peptic Ulcer Disease (PUD), Acute Pancreatitis, and A ruptured appendex

Question 3

What does the pathogenesis of acute pancreatitis usually involve?

Answer 3

Active secretion of pancreatic juice while the main pancreatic duct is OBSTRUCTED at its entrance into the duodenum.

Question 4

What is the pathogenesis of a ruptured appendix?

Answer 4

The colon wall tears open, allowing intestinal bacteria (“flora”) to escape to the abdominal and pelvic cavities, causing peritonitis or even death.

Question 5

What are the 4 tunics/layers of the GI from Lumen—>Out?

Answer 5

1.Mucosa 2.Submucosa 3.Muscularis Externa 4.Serosa (AKA Visceral Peritoneum

Question 6

Some smooth muscle cells are __________ that display rhythmic, spontaneous variations in membrane potential.

Answer 6

“pacemaker” cells

Question 7

What are the three names for the self-induced electrical activity in digestive smooth muscle? Are these used for tone or motility?

Answer 7

1.Slow-Wave potential 2.basal electrical rhythm(BER) 3.pacemaker potential…USED for tone

Question 8

What are the two plexi that are termed the intrinsic nerve plexus or the ENTERIC nervous system?

Answer 8

1.Submucosal Plexus 2.Myenteric Plexus

Question 9

Are the neurons of the enteric nervous system sensory or motor or both?

Answer 9

BOTH sensory and motor

Question 10

What are nerves that originate outside the GI tract and innervate the various GI organs – namely, nerve fibers from both branches of the autonomic nervous system?

Answer 10

Extrinsic Nerves

Question 11

What are the four parts of the GI tract innvervated by the VAGUS nerve? What % of the Vagus nerves are afferent?Efferent?

Answer 11

ALL UPPER! 1.Esophagus 2.Stomach 3.Small Intestine 4.Ascending Colon…75% Afferent…25%Efferent

Question 12

What nerves innervate the lower GI tract (Transverse, Descending, and Sigmoid colons and the anal canal)? What are the origins of these nerves?

Answer 12

The Pelvic Nerves (Pelvic Splanchnic)…Origins:S2,S3,S4 (keep the poo off the floor)

Question 13

What are the two types of POST ganglionic parasympathetic neurons servicing the GI? (think receptor type)

Answer 13

Cholinergic and Peptidergic

Question 14

What are the three sympathetic ganglia that serve the GI tract? What type of post-ganglionic fibers are they? What % are afferent/efferent?

Answer 14

1.Celiac 2.Superior Mesenteric 3.Inferior Mesenteric….Adrenergic(epi/norepi)…50%afferent/efferent

Question 15

What are the three ways autonomic nerves influence GI tract motility and secretion?

Answer 15

1.modifying the enteric nervous system 2.Alter GI hormone secretion 3. direct action on Smooth Muscle

Question 16

Which GI muscle layer will promote segmentation?

Answer 16

Circular Muscle

Question 17

Which GI muscle layer will promote peristalsis?

Answer 17

Longitudinal muscle

Question 18

The mucosa of certain regions of the GI tract contain endocrine cells that secrete _______.

Answer 18

Hormones

Question 19

GI hormones are carried through blood to other areas of the GI tract or accessory GI structures, where they exert either _______ or ________ influences on smooth muscle and exocrine cells.

Answer 19

excitatory or inhibitory