General Principles of GI Function

Question 1

Requirements of the GI System

Answer 1

Movement of food through the tract
Secretion of juices and digestion of food
Absorption of water, electrolytes, vitamins, and digestive products (nutrients)
Circulation of blood to carry absorbed materials
Control of these functions by local, nervous, and hormonal systems

Question 2

What cell type is the esophagus composed of?

Answer 2

Stratified squamous epithelium

Question 3

The junction connecting the esophagus to the stomach

Answer 3

Squamocolumnar Junction

Question 4

Two types of digestion done by the stomach

Answer 4

Mechanically and Chemically

Question 5

Thick layer of smooth muscle that regulates entry of material into the duodenum

Answer 5

Pyloric sphincter

Question 6

The Gastric Rugae of the stomach has these two functions

Answer 6

Allow the stomach to expand and help with mechanical churning

Question 7

Bile and pancreatic digestive enzymes are introduced here

Answer 7

Duodenum

Question 8

This is the primary region for nutrient absorption

Answer 8

Jejunum

Question 9

Which two parts of the small intestine are suspended in the mesentery?

Answer 9

Jejunum and Ileum

Question 10

Which region is commonly associated with Crohn’s disease?

Answer 10

The illeocecal junction

Question 11

Length of the Large intestine

Answer 11

1.5 Meters

Question 12

Colons main function

Answer 12

Absorbs water and electrolytes from the remaining digestive material

Question 13

Area between the descending colon and rectum

Answer 13

Sigmoid colon

Question 14

The muscular band that runs longitudinally on the large intestine

Answer 14

Teniae Coli

Question 15

What does Haustral Churning do?

Answer 15

Haustral churning leads to mixing, helping to expose all of the stool to mucosal surface for better absorption.

Question 16

The neural sensation that suggests the need for a bowel movement is triggered by _____ of the rectum

Answer 16

Expansion

Question 17

Fecal impactions can occur in the ____

Answer 17

Rectum

Question 18

Accessory digestive muscles of the hepatobiliary tree

Answer 18

Liver
Gallbladder
Network of ducts
(Pancreas)

Question 19

Two types of muscle in the muscularis layer of the GI wall

Answer 19

Longitudinal and circular smooth muscle

Question 20

Which layer of the GI wall contains the lamina propria?

Answer 20

Mucosa

Question 21

Which layer of the GI wall contains blood vessels, lymphatic vessels, and nerves?

Answer 21

Submucosa

Question 22

Outermost layer of the GI Wall and what it is made of

Answer 22

The Serosa is a connective tissue covering that encases and protects the organ.

Question 23

Three main branches of the celiac trunk

Answer 23

Common Hepatic Artery
Left Gastric Artery
Splenic Artery

Question 24

The superior mesenteric artery supplies blood to

Answer 24

Most of the small intestine
The pancreas
The proximal half of the large intestine

Question 25

The inferior mesenteric artery supplies blood to

Answer 25

The descending colon The sigmoid colon The rectum

Question 26

Two main types of GI Blood flow modulators

Answer 26

Gut Activity / Metabolic Factors- Release of vasodilators Decreased oxygen concentration Nervous System Input- Autonomic Nervous System

Question 27

The goal of the Hepatic portal system is to

Answer 27

drains blood from the GI tract and takes blood to the liver for further absorption and processing of material

Question 28

These hormones have a vasodilatory effect on the digestive process

Answer 28

Cholecystokinin Vasoactive Intestinal Peptide Gastrin Secretin

Question 29

Two things that parasympathetic stimulation increases in GI blood flow

Answer 29

Increases local blood flow Increases glandular secretions

Question 30

A fight or flight response will cause

Answer 30

intense vasoconstriction throughout the GI tract, pushing blood out of the gastrointestinal tract and into the brain, lungs, and skeletal muscles

Question 31

Where is the enteric nervous system found

Answer 31

lies entirely within the wall of the gut, beginning in the esophagus and ending at the anus

Question 32

Two parts of the enteric nervous system

Answer 32

Myenteric Plexus (AKA Auerbach’s Plexus): Lies between the longitudinal and circular muscle layers, concerned mainly with controlling muscle activity along the length of the gastrointestinal tract. Submucosal Plexus (AKA Meissner’s Plexus): Lies in the Submucosa, mainly functions to control the gastrointestinal secretions, local absorption, and local blood flow within the wall.

Question 33

T/F - the Enteric Nervous System can function independently of any extrinsic neuronal input

Answer 33

T

Question 34

Post-Ganglionic neurons from the ____ chain secrete norepinephrine on GI smooth muscle and Enterics (inhibitory action on digestion)

Answer 34

Sympathetic

Question 35

Propolsive vs. Mixing movements

Answer 35

Propulsive Movements- Cause food products to move forward along the tract at an appropriate rate to accommodate digestion and absorption. Mixing Movements- Keep the intestinal contents thoroughly mixed at all times.

Question 36

GI Movement is influenced by these two things

Answer 36

Autonomic Input and GI Hormones

Question 37

This GI Hormone increases GI motility

Answer 37

Motilin

Question 38

Mixing movements are also mostly triggered by ____

Answer 38

luminal distention of the gut

Question 39

Two requirements for peristalsis

Answer 39

Intact Myenteric Plexus of the Enteric Nervous System, as well as a fully functional Autonomic Nervous System