Section 1B

Question 0

Technically, contents within the lumen are where?

Answer 0

Outside the body.

Question 1

The lumen of the GI tract is continuous with what??

Answer 1

The external environment

Question 2

Why is it important to know that the about the GI tract environment being technically “outside the body”

Answer 2

This fact is important because conditions essential to the digestive process can be tolerated in the GI tract lumen but are generally not tolerated in the body proper. When contents escape from the GI tract lumen, they can produce symptoms that often indicate GI dysfunction

Question 3

What occurs during a peptic ulcer disease?

Answer 3

Gastric juice penetrates the gastric mucosal barrier, injuring the gastric wall with its acidic and enzymatic contents

Question 4

What occurs in acute pancreatitis?

Answer 4

Pancreatic juice escapes the pancreas and or duodenum

Question 5

What are the four layers of the anatomy of the GI tract wall (from inside to outside)

Answer 5

1. Mucosa
2. Submucosa
3. Muscularis Externa
4. Serosa (visceral peritoneum)

Question 6

Explain the pathogenesis of acute pancreatitis

Answer 6

Usually involves active secretion of pancreatic juice while the main pancreatic duct is obstructed at its entrance into the duodenum. The build-up of obstructed secretions greatly increases the pressure within the duct causing the ducts to rupture and pancreatic juice to escape

Question 7

What occurs in the case of a ruptured appendix

Answer 7

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

Question 8

What is the slow-wave potential

Answer 8

prominent type of self-induced electrical activity in digestive smooth muscle. The pacemaker cell activity of some smooth cells

Question 9

What is the alternate term for slow-wave potential

Answer 9

Basal Electrical Rhythm or

Pacemaker potential

Question 10

What makes up the enteric nervous system?

Answer 10

Neurons of the submucosal and myenteric plexuses. Also termed the intrinsic nerve plexuses or enteric nervous system

Question 11

T or F, The neurons of the intrinsic nervous system are both sensory and motor

Answer 11

True

Question 12

The motor neurons of the enteric nervous system innervate what 3 types of cells?

Answer 12

1. Smooth muscle cells
2. Exocrine cells
3. Endocrine cells

Question 13

What parasympathetic nerves innervate the upper GI tract?

Answer 13

Vagus nerves

Question 14

What four things of the upper GI tract are innervated by the vagus nerve?

Answer 14

Esophagus
Stomach
Small Intestine
Ascending Colon

Question 15

What percentage of the vagus nerves innervating the upper GI tract are considered afferent and efferent?

Answer 15

75% Afferent

25% Efferent

Question 16

What parasympathetic nerves innervate the lower GI tract

Answer 16

Pelvic Nerves (pelvic splanchic)

Question 17

What parts of the lower GI tract are innervated by the pelvic nerves

Answer 17

Transverse, descending and sigmoid colons

Anal canal

Question 18

The pelvic nerves derive from what spinal nerve pairs?

Answer 18

S2, S3, S4

Question 19

Majority of parasympathetic post-ganglionic neurons are what type?

Answer 19

Cholinergic

Some are peptidergic

Question 20

What are the 3 sympathetic ganglia that service the GI tract?

Answer 20

Celiac
Superior Mesenteric
Inferior Mesenteric

Question 21

The post-ganglionic sympathetic fibers are what type of neuron?

Answer 21

Adrenergic

Question 22

What percentage of sympathetic fibers are efferent and afferent that service the GI tract?

Answer 22

50% of each

Question 23

Autonomic nerves influence GI tract motility and secretion either by what 3 ways?

Answer 23

1. Modifying ongoing activity in the enteric nervous system
2. Altering the level of GI hormone secretion
3. Acting directly on smooth muscle and glands

Question 24

What layer of the GI tract contain endocrine cells that secrete hormones?

Answer 24

Mucosal layer