Chapter 6: Gastrointestinal Physiology

Question 1

Layer of GI tract that are specialized in different parts of the GI tract for secretion or absorption

Answer 1

Epithelial cells/Epithelium

Question 2

Layer of GI tract wherein its contraction causes a change in the surface area for secretion or absorption

Answer 2

Muscularis mucosa

Question 3

Layer of GI tract wherein its contraction causes a decrease in diameter of the lumen of the GIT

Answer 3

Circular muscle

Question 4

Layer of GI tract wherein its contraction causes shortening of a segment of the GIT

Answer 4

Longitudinal muscle

Question 5

Submucosal plexus is also known as

Answer 5

Meissner’s plexus

Question 6

Myenteric plexus is also known as

Answer 6

Auerbach’s plexus

Question 7

The parasympathetic nervous system is _____ on the functions of the GIT

Answer 7

excitatory

Question 8

The parasympathetic nervous system of the GIT is carried by what nerves

Answer 8

Vagus and pelvic nerves

Question 9

This nerve innervates the esophagus, stomach, pancreas and upper large intestine

Answer 9

Vagus nerve

Question 10

This nerve innervates the lower large intestine, rectum, anus

Answer 10

Pelvic nerve

Question 11

The sympathetic nervous system is _____ on the functions of the GIT

Answer 11

inhibitory

Question 12

Fibers of the SNS of the GIT originate in the spinal cord between __ and __

Answer 12

T8 and L2

Question 13

This type of innervation uses local reflexes to relay information within the GIT

Answer 13

Intrinsic innervation

Question 14

This plexus primarily controls the motility of the GI smooth muscle

Answer 14

Myenteric or Auerbach plexus

Question 15

This plexus primarily controls secretion and blood flow

Answer 15

Submucosal or Meissner plexus

Question 16

The 4 official GI hormones

Answer 16

Gastrin
Cholecystokinin
Secretin
Glucose-dependent Insulinotropic peptide (GIP)

Question 17

Gastrin is secreted from

Answer 17

G cells of the gastric antrum

Question 18

These amino acids are the most potent stimuli for gastrin secretion

Answer 18

Phenylanine and Tryptophan

Question 19

This type of gastrin is the form secreted in response to a meal and it contains how many amino acids?

Answer 19

Little gastrin

17 amino acids

Question 20

All of the biologic activity of gastrin resides in the _____

Answer 20

four C-terminal amino acids

Question 21

This type of gastrin contains 34 amino acids

Answer 21

Big gastrin

Question 22

GI hormone that increases H+ secretion by gastric parietal cells and stimulates growth of gastric mucosa

Answer 22

Gastrin

Question 23

Inhibitors of gastrin secretion

Answer 23

H+ in the stomach

Somatostatin

Question 24

Stimuli for gastrin secretion

Answer 24

Small peptides and amino acids in the stomach
Stomach distention
Vagal stimulation

Question 25

Hormone that is homologous to gastrin

Answer 25

Cholecystokinin

Question 26

Cholecystokinin is secreted by

Answer 26

I cells of duodenum and jejunum

Question 27

Hormone that causes contraction of gallbladder and relaxation of sphincter of Oddi

Answer 27

Cholecystokinin

Question 28

GI hormone that inhibits gastric emptying to allow more time for intestinal digestion and absorption

Answer 28

Cholecystokinin

Question 29

``` The following are stimuli for CCK release EXCEPT: Small peptides and amino acids Fatty acid Triglycerides Monoglycerides ```

Answer 29

Triglycerides

Question 30

GI hormone homologous to glucagon

Answer 30

Secretin

Question 31

Secretin is released by:

Answer 31

S cells of duodenum

Question 32

Stimuli for Secretin release

Answer 32

H+ in the duodenum | Fatty acids in the duodenum

Question 33

Inhibits H+ secretion by the parietal cells

Answer 33

Secretin | GIP

Question 34

Homologous to secretin and glucagon

Answer 34

Glucose-dependent insulinotropic peptide (GIP)

Question 35

Only hormone that is released in response to fat, protein and carbohydrates

Answer 35

GIP

Question 36

GIP is secreted in the

Answer 36

duodenum and jejunum

Question 37

Actions of GIP

Answer 37

Stimulates insulin release | Inhibits H+ secretion

Question 38

Decreases appetite

Answer 38

Leptin

Question 39

Increases appetite

Answer 39

Ghrelin

Question 40

GI paracrines

Answer 40

Somatostatin | Histamine

Question 41

Inhibits the release of all GI hormones

Answer 41

Somatostatin

Question 42

Histamine is secreted by

Answer 42

Mast cells of the gastric mucosa or the enterochromaffin-like cells (ECL)

Question 43

GI neurocrines

Answer 43

``` Vasoactive intestinal peptide (VIP) Neuropeptide Y Nitric Oxide (NO) GRP (bombesin) Enkephalins ```

Question 44

GI neurocrine homologous to secretin

Answer 44

VIP

Question 45

GI neurocrine released from vagus nerves that innervate the G cells

Answer 45

GRP

Question 46

Action of GRP

Answer 46

stimulates gastrin release from G cells

Question 47

Satiety center is located in

Answer 47

ventromedial nucleus of the hypothalamus

Question 48

Feeding center is located in

Answer 48

lateral hypothalamic area of the hypothalamus

Question 49

Leptin is secreted by these cells

Answer 49

Fat cells

Question 50

Ghrelin is secreted by these cells

Answer 50

Gastric cells

Question 51

Oscillating membrane potentials inherent to smooth muscle cells of GIT

Answer 51

Slow waves

Question 52

Slow waves originate in these cells

Answer 52

Interstitial cells of Cajal

Question 53

Frequency of slow waves is lowest in

Answer 53

stomach ( 3 slow waves/min)

Question 54

Frequency of slow waves is highest in

Answer 54

duodenum (12 slow waves/min)

Question 55

Swallowing reflex is coordinated in

Answer 55

medulla

Question 56

This type of contraction mix the intestinal contents

Answer 56

Segmentation contractions

Question 57

This type of contractions propel the chyme through the small intestine

Answer 57

Peristaltic contractions

Question 58

Enterochromaffin cells release this NT

Answer 58

Serotonin

Question 59

Peristaltic reflex is coordinated in the

Answer 59

enteric nervous system

Question 60

This initiates the peristaltic reflex

Answer 60

Serotonin binding to receptors on intrinsic primary afferent neurons (IPANs)

Question 61

This type of contractions are responsible for the appearance of haustra in the large instestine

Answer 61

Segmentation contractions

Question 62

Urge to defecate is felt when rectum is filled to this percent

Answer 62

25%

Question 63

Intra-abdominal pressure is increased by expiring against a closed glottis

Answer 63

Valsalva maneuver

Question 64

As the rectum fills with fecal material, it contracts and the internal anal sphincter relaxes

Answer 64

Rectosphincteric reflex

Question 65

The presence of food in the stomach increases the motility of the colon and increases the frequency of mass movements

Answer 65

Gastrocolic reflex

Question 66

Increased segmentation contractions results to this symptom

Answer 66

Constipation

Question 67

Decreased segmentation contractions results to this symptom

Answer 67

Diarrhea