Deck 57: Intestinal and Colonic Motility

Question 1

Relaxation of the internal anal sphincter is caused by

A) Nutrients in the ileum
B) Stretch of the ascending colon
C) Stretch of the ileum
D) Stretch of the stomach
E) Stretch of the sigmoid colon and rectum

Answer 1

E

Question 2

Preganglionic parasympathetic nerves in the small intestine release

A) Acetylcholine onto muscle cells
B) Acetylcholine onto neurons in the myenteric plexus
C) N or ep ine ph rin e o nto m us cle ce lls
D) Norepinephrine onto neurons in the myenteric plexus
E) VIP an d N O on to m us cle ce lls

Answer 2

B

Question 3

The groups of neurons between the outer longitudinal and inner circular muscle layers is the

A) Myenteric plexus
B) Submucosal plexus
C) Interstitial cells of Cajal
D) Celiac ganglion
E) Inferior mesenteric ganglion

Answer 3

A

Question 4

Pe ris tals is is initia ted by

A) Interstitial cells of Cajal
B) Longitudinal muscle contraction and circular muscle relaxation orad
C) Longitudinal muscle relaxation and circular muscle contraction caudad
D) Intrinsic primary afferent neurons
E) Parasympathetic nervous stimulation

Question 5

Which of the followin g sta tem ents abo ut the bas ic elec trical rhythm is NO T tru e?

A) The basic electrical rhythm is set by interstitial cells of Cajal
B) T he ba sic ele ctr ica l rhyt hm is a bo ut 1 0- 12 m in-1 in the duodenum
C) The rate of the basic electrical rhythm Increases from orad to caudad
D) The frequency of intestinal contractions is set by the basic electrical rhythm
E) Parasympathetic stimulation does not alter the frequency of the basic electrical rhythm

Question 6

The duodenum

A) Is the first p art of th e sm all intestin e from the p yrloric sp hinc ter to th e su spe nso ry ligament, about 20 cm
B) Connects the stomach to the ileum
C) Connects the ileium to the colon
D) Is the middle part of the small intestine, about 40% of the length of the small intestine
E) Is the last part of the small intestine, about 60% of the length of the small intestine

Question 7

The caliber of the gut (its cross-sectional profile) is set by the

A) Outer longitudinal muscle layer
B) Inner longitudinal muscle layer
C) Outer circular muscle layer
D) Inner circular muscle layer
E) Muscularis mucosa

Question 8

Haustra

A) Result from peristalsis in the large intestine
B) R es ult f ro m loc al c on tra ctio ns of t he ten ia c oli
C) Re su lt from loca l con trac tion s of the circu lar m us cle
D) Are present only during giant migrating contractions
E) Move fecal material caudad

Question 9

Sem entation contractions

A) Are local contractions of the circular muscle layer
B) Are local contractions of the longitudinal muscle layer
C) Are initiated by the parasympathetic nerves
D) Result from vagovagal reflexes
E) Move m aterial only in the orad to caudad direction

Question 10

In the ascending contraction

A) Longitudinal muscle relax orad, circular muscles contract orad
B) Longitudinal muscles contract orad, circular muscles relax orad
C) Longitudinal muscles relax caudad, circular muscles contract caudad
D) Longitudinal muscles relax both caudad and orad
E) A and C are correct

Question 11

In p er ista lsis

A) Longitudinal muscle relax orad, circular muscles contract orad
B) Longitudinal muscles contract orad, circular muscles relax orad
C) Longitudinal muscles relax caudad, circular muscles contract caudad
D) Longitudinal muscles relax both caudad and orad
E) A and C are correct

Question 12

Which of the following is NO T involved with sympa thetic innervation to the GI tract?

A) Celiac ganglion
B) Inferior mesenteric ganglion
C) Superior mesenteric ganglion
D) Splanchn ic nerve
E) Pelvic nerve

Question 13

In the descending relaxation

A) Longitudinal muscle relax orad, circular muscles contract orad
B) Longitudinal muscles contract orad, circular muscles relax orad
C) Longitudinal muscles contract caudad, circular muscles relax caudad
D) Longitudinal muscles relax both caudad and orad
E) A and C are correct

Question 14

Which of the followin g sta tem ents abo ut se gm enta tion co ntac tions is NO T tru e?

A) Segmentation contractions move food surfaces around for digestion and absorption
B) Segmentation contractions mix food with digestive juices
C) Segmentation contractions move m aterial both caudad and orad
D) Segmentation contractions are more frequent in the distal small intestine
E) Segmentation contractions occur only in the digestive period

Question 15

Which of the following is NOT part of the large intestine?

A) Cecum
B) Ascending colon
C) Descending colon
D) Sigmoid colon
E) Reversing colon

Question 16

Increased colonic motility following a meal is the result of the

A) Gastrocolic reflex
B) Gastroileal reflex
C) Gastric accomm odation
D) Enterogastric inhibitory reflex
E) Receptive relaxation

Question 17

The pattern of gut motility during the interdigestive period is called

A) Segmentation
B) Pe ris tals is
C) Quiescence
D) Migrating myoelectric complex
E) M otilin

Question 18

The Migrating motility complex

A) Occurs imm ediately following a meal
B) M ixes chyme
C) Is in vo lve d in rev er se pe ris tals is
D) Closes the ileoceca l valve
E) Sweeps everything caudad

Question 19

Relaxation of intestinal smooth m uscle by symp athetic innervation is caused by activation of

A) þ
B) þ
C) a
D) C ho line rg ic re ce pto rs on the m us cle
E) a

Question 20

Giant migrating contractions

A) Have small amplitudes but occur at high frequency
B) Mo ve fecal material caudad for extended distances
C) Appear only during the digestive period
D) Are mediated by sympathetic nerves
E) Refer to contractions in the ileum

Question 21

The ch em ica l trig ge r zo ne is

A) An area of the medulla whose stimulation by specific chemicals causes vomiting
B) A group of chemoreceptors in the carotid body
C) A group of chemoreceptors in the aortic arch
D) A collection of solitary chemoreceptor cells in the intestine that induce vomiting
E) An integrative center in the medulla that coordinates vomiting

Question 22

The external anal sphincter is controlled by

A) Reflexes from stretch of the sigm oid colon m ediated by the parasym pathetic nerve
B) Involuntary reflexes c arried over the pelvic nerve
C) Somatic motor neurons from sacral segments carried in the pudendal nerve
D) Sym pathetic nerves from T10-L 2 over the hypogastric nerve
E) Involuntary reflexes c arried over the pudend al nerve

Question 23

Increased diffuse colonic activity after eating a meal is called the

A) Enterogastric excitatory reflex
B) Enterogastric inhibitory reflex
C) Ileal brake
D) Gastrocolic reflex
E) Gastoileal reflex

Question 24

The ga str oc olic ref lex is

A) Increased stomach motility after a meal
B) Relaxation of the stomach during a meal
C) Decreas ed sto m ac h e m ptyin g u ntil c hym e p ar ticle size is s m all
D) Increased colonic activity upon stretch of the stomach
E) Increased colonic activity upon stretch of the ileum

Question 25

Nutrients in the terminal ileum

A) Inhibit gastric emptying in a reflex called the ileal brake
B) Inhibit ileal m otility
C) Close the ileocecal valve
D) Stim ulate c olon ic m otility
E) Stim ula te d uo de na l pe ris tals is

Question 26

Which of the following generally is NOT a stimulus for vomiting?

A) Motion sickness
B) GI irritants such as syrup of ipecac
C) Noxious odors
D) The gag reflex
E) Sexually suggestive photographs

Question 27

The vomiting center is located in the

A) M ed ulla
B) Pons
C) Cerebellum
D) Hypothalamus
E) Ba sa l ga ng lia

Question 28

On e of th e m ain fu nction s of th e ileoc eca l valve o r sph incter is to

A) Keep ileal contents in the ileum
B) Prevent reflux of cecal contents into the ileum
C) Limit peristalsis to the small intestine
D) Prevent diarrhea
E) Allow diarrhea

Question 29

Vom iting of stomach contents alone should

A) Increase the alkalinity of blood by losing acid from the body
B) Increase th e a cid ity of blo od by c om pe ns atin g fo r th e lo st a cid
C) Have no eff ec t on the pH of t he blo od be ca us e o f th e c om pe ns atio n b y the pa nc re atic secretions
D) Increase the C l- concentration of blood by losing more water than Cl-
E) Decrease the Na+ concentration of blood by losing more Na+ than water