GI 1

Question 1

Duodenal Cluster (3)

Answer 1

1. Duodenum
2. Pancreas
3. Biliary System

Question 2

Biliary System

Answer 2

the organs and ducts (bile ducts, gallbladder, and liver) associated with production/transportation of bile

Question 3

Sphincter of Oddi

Answer 3

at the jxn of bile ducts and duodenum, controls when bile and pancreatic sercretions are realeased into the lumen of the duodenum

Question 4

3 Parts of the Small Intestine

Answer 4

1. Duodenum
2. Jejunum
3. Ileum

Question 5

Function of Jejunum

Answer 5

site of the majority of nutrient absoprtion

Question 6

Function of the Colon

Answer 6

absorb water andd electrolytes, store wastes ad indigestibles

Question 7

Flow of the GI tract

Answer 7

oral cavity –> esophagus –> stomach –> duodenl cluster –> jejunum –> ileum –> colon –> rectum –> anus

Question 8

Pylorus

Answer 8

controls outflow from stomach

Question 9

Upper and Lower Esophageal Sphincters

Answer 9

control swallowing and reflux

Question 10

Ileocecal valve

Answer 10

at jxn of small intestine and colon; one way valve that keeps GI bacteria in the colon and allows other residues from the small intestine to pass through

Question 11

Internal and External anal sphincters

Answer 11

control defecation

Question 12

Mucosal Plica

Answer 12

the folds in the lumen of the GI tract

Question 13

What sits on the folds of the mucosal plicae?

Answer 13

Villi and microvilli, to aid in efficient digestion and absorption

Question 14

Label the layers of the GI Wall

Answer 14

Question 15

Components of the Submucosa of the GI Wall

Answer 15

loose connective tissue, arteries, veins, lymphatics, submucosal plexus [ganglia] (at the base)

Question 16

Components of the Muscularis Layer of the GI Wall

Answer 16

Internal Circular Muscle Layer
Myenteric Plexus (in the middle)
External Longitudinal Muscle Layer

Question 17

What are the two main functions of the intestinal epithelium?

Answer 17

secretion and absorption

Question 18

How often is all of the intestinal epithelium replaced?

Answer 18

every 2-5 days

Question 19

Types of Cells in the Intestinal Epithelium (6)

Answer 19

1. Intestinal stem cells
2. Paneth cells
3. Transit Amplifying cells
4. Goblet cells
5. Enteroendocrine cells
6. Enterocytes

Question 20

What type of cells make up the majority of the intestinal epithelium?

Answer 20

enterocytes (secrete enzymes and absorb nutrients)

Question 21

Paneth cell function

Answer 21

secret antimicrobial peptides

Question 22

What percent of the intestinal epithelium do enteroendocrine cells make up?

Answer 22

1%

Question 23

Enteroendocrine cell function

Answer 23

secrete hormones

Question 24

Crypt

Answer 24

an invagination of the intestinal lumen that has cells of primarily secretion capabilities

Question 25

The enteric nervous system is a branch of what part of the peripheral nervous system?

Answer 25

autonomic (involuntary control)

Question 26

What do we consider the extrinsic nervous system of the GI tract?

Answer 26

Autonomic Nervous System

Question 27

The Two (2) Main Ganglia of the Enteric Nervous System

Answer 27

1. Myenteric Plexus 2. Submucosal Plexus

Question 28

Since the enteric nervous system can function as a loop on its own, what do we call those loops?

Answer 28

microcircuits

Question 29

What two nerves of the parasympathetic nervous system innervate the GI?

Answer 29

1. Vagal nerves 2. Pelvic nerves

Question 30

What type of fibers of the parasympathetic system synapse on the GI - pre or post ganglionic?

Answer 30

preganglionic

Question 31

Where do the fibers of the parasympathetic innervation of the GI originate from?

Answer 31

the medulla and the sacrolumbar region (mostly sacral)

Question 32

Where do the fibers of the sympathetic innervation of the GI originate from?

Answer 32

thoracolumbar region

Question 33

What type of fibers of the sympathetic system synapse on the GI - pre or post ganglionic?

Answer 33

postganglionic

Question 34

Where do the preganglionic fibers of the sympathetic nervous system synapse?

Answer 34

prevertebral ganglia (sympathetic trunk)

Question 35

Does the myenteric plexus extend the entire length of the gut?

Answer 35

yes (including striated muscle of the esophagus)

Question 36

Primary function of the Myenteric Plexus?

Answer 36

motor innervation to the longtitudinal and circular muscle layers

Question 37

Where along the GI tract will you find the most submucosal plexus?

Answer 37

small intestine, specifically the proximal duodenum

Question 38

Main function of the Submucosal Plexus

Answer 38

secretory control

Question 39

Explain the microcircuit of the intrinsic nervous system

Answer 39

Sensory (afferent) neurons receive input (chemo or mechano), sensory fibers communicate with interneurons along the myenteric plexus, motor neurons then carry the signal back to the lumen (result dependent on NTs whether stim or inhibits)

Question 40

Varicosities

Answer 40

endings of nerve fibers similar to a motor plate in skeletal muscle, but more multiple swellings that contain vesicles with neurotransmitters

Question 41

3 Main Functions of Submucosal Plexus

Answer 41

To Moderate: 1. Secretory Activity 2. Endocrine Activity 3. Blood Flow

Question 42

2 Main Functions of the Myenteric Plexus

Answer 42

To Control: 1. Tonic Contractions 2. Rhythmic Contraction intensity

Question 43

2 Types of Contractions in the GI Tract

Answer 43

1. Tonic 2. Rhythmic

Question 44

Tonic Contractions

Answer 44

typically around sphincters, long lasting weaker contraction

Question 45

Rhythmic Contraction

Answer 45

strong contractions to propel food along the GI tract and also mix food with digestive secretions

Question 46

What nervous system has fibers that can synapse directly on target cells - pre or postganglionic?

Answer 46

Sympathetic postganglionic fibers

Question 47

What nervous system contains 50% sensory and 50% motor?

Answer 47

sympathetic

Question 48

Vagovagal reflex

Answer 48

both sensory and motor neurons of the vagus nerve communicate with the CNS to coordinate responses to gut stimuli

Question 49

What NTs work with the parasympathetic fibers in the GI tract?

Answer 49

acetylcholine or peptides

Question 50

What NTs work with the POSTganglionic sympathetic fibers of the GI tract?

Answer 50

norepinephrine

Question 51

What NTs work with the PREganglionic sympathetic fibers of the GI tract?

Answer 51

Acetylcholine

Question 52

Long loop reflex

Answer 52

the coordination of the enteric nervous system with the CNS in response to fight or flight response or anticipation of food

Question 53

Short loop reflex

Answer 53

essentially a summary of all the microcicuits of the enteric nervous system (it communicates with itself to initiate a response)

Question 54

What are some stimuli that can affect the GI tract?

Answer 54

CNS influence, physical environment (lumen pressure, distention), chemical environment (pH, nutrient conc.), microbes