MOTO GI snitches (Q1-60.)

Which shows normal pressure tracing at the level of the LES ANSWER

trace A shows a normal pressure tracing at the level of the LES reflecting typical receptive relaxation in response to the food bolus.

Partial gastrectomy of proximal 1/3 of stomach. What process will be affected?

(A) Accommodation *receptive relaxation is a function only of the orad region. w/o it, no accommodation*

Vago-vagal reflex

(1) increase gastric compliance (receptive relaxation or accommodation reflex) and promote gastric retention of food, (2) increase the strength of antral peristaltic contractions necessary for trituration of solids, and (3) increase gastric acid secretion. S

What ions has the highest concentration in saliva under basal conditions?

(A) Bicarbonate potassium con. in saliva is about 7x greater than plasma, and bicarb conc. in saliva is only about 3x. than plasma. HOWEVER. the actual conc. of bicar in saliva is 50-70 mEq/L, and conc. of potassium is about 30 mEq/L,

Mass movements are often stimulated after a meal by distention of the stomach (gastrocolic reflex) and distention of the duodenum (dundenocolic reflex). Mass movements often lead to What?

(A) Bowel movements Mass movements force feces into the rectum *When the walls of the rectum are stretched by the feces, the defecation reflex is initiated and a bowel movement follows when this is convenient.*

The major stimulus for receptive relaxation of the stomach is...

(A) Food in the stomach *When food distends the orad stomach, it produces a vagovagal reflex by which non-cholinergic, non-adrenergic fibers relax the stomach

tonicity of saliva

(A) Hypotonicity relative to plasma *hypotonic & high bicarb* presence of α-amylase and lingual lipase (not proteases).

Efferent impulses from vagal fibers to stomach may mediate:

(A) Increase strength of gastric peristalsis (B) Relaxation of the gastric fundus during swallowing (C) Increased secretion from parietal cells Vagal to stomach increases after a meal and promotes both motor and secretory activity. also relaxes proximal stomach

#41 In a normal individual, the enterogastric reflex will be elicited by:

(A) Increased duodenal wall tension (B) Irritation of small intestine mucosa (C) Protein metabolites in the duodenum (D) Acid chyme in the duodenum *The enterogastric reflex which slows activity in the stomach will be initiated by anything that increases activity in the small intestine.*

What happens to anal sphincters during defecation?

(A) Internal/external anal sphincters relaxed *Rectal smooth muscle contracts and intra-abdominal pressure is elevated by expiring against a closed glottis (Valsalva maneuver)*

Buffet. The rate of gastric emptying increases with an increase in which of the following?

(A) Intragastric volume *The initial rate of emptying varies directly with the volume of the meal ingested.*

Which of the following structures undergoes receptive relaxation when a bolus of food is swallowed?

(A) Orad stomach *During a swallow, the orad portion of the stomach and lower esophageal sphincter relax at about the same time*

The strength of peristaltic waves passing over the stomach is influenced by:

(A) Presence of 2-monoglycerides in the duodenum (B) Distension of duodenum (C) Osmotic pressure of chyme leaving the stomach (D) Rate of release of adrenergic substances in the intrinsic plexus *Fat (via GIP), distension (reflex), high osmotic pressure, and ACID CAUSING RELEASE OF SECRETIN*

Which of the following secretions is most dependent on neural stimulation? (A) Saliva (C) Pepsin (E) Bile (B) Hydrochloric acid (D) Pancreatic juice

(A) Saliva Salivary flow is entirely dependent on the autonomic nervous system (ANS). *PSNS stim: watery (large volume* *SNS stim: protiens (mucus & enzymes* Secretion (HCI), pepsin, pancreatic juice, and bile is influenced by vagal stimulation but can occur without it.

Which of the following best describes the condition for which the patient received pelvic floor training?

(C) Fecal incontinence (i.e., no control over defecation) *the external anal sphincter was unchanged following inflation of the rectal balloon. This failure of the external anal sphincter to contract is expected to result in defecation.*

All of the following would generally depolarize intestinal smooth muscle EXCEPT: A) Distension (D) Myenteric plexus activation (B) Adrenergic transmitters (E) Vagal discharge (C) Cholinergic agents

(B) Adrenergic transmitters *adrenergic activity to the gut inhibits smooth muscle and decreases activity.*

Gastric emptying is regulated to ensure the chyme enters the duodenum at an appropriate rate. Which of the following factors promotes gastric emptying?

(B) Antral peristalsis

vagotomy. then experiences nausea and vomiting after ingestion of a mixed meal. Which of the following best explains her symptoms?

(B) Decreased gastric emptying of solids

40 min after meal the ileocecal sphincter relaxes and chyme moves into the cecum. Gastric distention leads to relaxation of the ileocecal sphincter by way of which reflex?

(B) Gastroileal reflex * Relaxation of the ileocecal sphincter occurs with or shortly after eating. This reflex is called the gastroileal reflex*

Compared to fluid in a salivary gland acinus, the fluid at the duct opening in the mouth will have a:

(B) Lower osmolarity *The ducts of salivary glands reabsorb Na+ and Cl-, and secrete K+.* (low flow rate), saliva is hypotonic

The major stimulus for primary peristalsis in the esophagus is...

(B) Swallowing *Primary esophageal peristalsis is part of the swallowing response and occurs whether or not food enters the esophagus.*

20 min after meal, has urge to defecate. What reflexes results in the urge to defecate when the stomach is stretched?

(C) Gastrocolic reflex *The gastrocolic reflex occurs when distension of the stomach (gastro) stimulates mass movements in the colon (colic*

mom concerned that her infant defecates after every meal. What reflex is the cause of these normal bowel movements in newborns?

(B) The gastrocolic reflex *Distention of the stomach by food initiates contraction of the rectum and often, a desire to defecate. This response is called the gastrocolic reflex*

Acetylcholine (ACh) is required for the contraction of LES, UES, or both?

(B) The upper esophageal sphincter (UES) *UES: striated cholinergic (ach)* *LES: smooth muscle: myogenic process*

What is the putative inhibitory neurotransmitter responsible for relaxation of gastrointestinal smooth muscle?

(B) Vasoactive intestinal peptide * Important inhibitory neurotransmitters in the gastrointestinal tract include vasoactive intestinal peptide and nitric oxide.*

type 1 DM w/ Gastroparesis w/ GERD. Which of the following best describes the function of gastric emptying?

(C) Hyperosmolality of duodenal contents initiates a decrease in gastric emptying *Gastroparesis is common in diabetes mellitus because hyperosmolality of the duodenum initiates a decrease in gastric emptying, which is probably neural in origin and is sensed by duodenal osmoreceptors*

What is X ? Answer

(C) Internal anal sphincter

Migrating motility complexes (MMC)-every 90 min between meals and are stimulated by motilin. An absence of MMCs causes an increase in ?

(C) Intestinal bacteria *by sweeping undigested food residue from the stomach, through the small intestine, and into the colon, MMCs function to maintain low bacterial counts in the upper intestine.*

Normally, which of the following is most likely regarding reflux of gastric acid into the esophagus?

(C) It initiates secondary esophageal peristalsis

Vagotomy. What gastrointestinal motor activities will be affected most?

(C) Orad stomach accommodation *need intact vago-vagal reflex.*

What structures is critical for determining whether a bolus of food is small enough to be swallowed?

(C) Palatopharyngeal folds *The palatopharyngeal folds located on each side of the pharynx are pulled medially forming a sagittal slit through which the bolus of food must pass.*

newborn, distended ab. no merconium w/in 48 hr. Hirschsprungs. The absence of which type of cell is diagnostic for Hirschsprung disease?

(C) Parasympathetic ganglion cells absence of parasympathetic ganglion cells in the myenteric and submucosal plexus of the rectum and/or colon. *begins with the anus, which is always involved, and continues proximally for a variable distance*

Compared to plasma, saliva has the highest relative concentration of what ion under basal conditions?

(C) Potassium *primary secretion of saliva by acini is ionic (similar to plasma). As the saliva flows through the ducts, sodium ions are actively reabsorbed and potassium ions are actively secreted in exchange for sodium.*

vomiting shortly after a meal reveal a time to one-half emptying of liquids of 18 minutes (normal < 20 minutes) and a time to one-half emptying of solids to be 150 minutes (normal < 120 minutes). Which of the following best explains the data?

(C) Pyloric stenosis *emptying of solids from the stomach is determined by 1. the strength of antral peristaltic contractions 2. resistance offered by the pyloric sphincter. Either a decrease in the amplitude of the antral contractions or an increase in sphincter resistance will delay the emptying of solids from the stomach.*

DM type 1 takes metoclopramide because of severe gastroparesis. Which of the following would be expected ?

(D) It increases peristalsis of the small intestine * Metoclopramide is used as a motility agent in patients with diabetic gastroparesis. 1. increases parastalysis of S.I. 2. increases LES

what would abolish "receptive relaxation" of the stomach?

(C) Vagotomy *"Receptive relaxation" of the orad is initiated when food enters the stomach This parasympathetic (vagovagal) reflex is abolished by vagotomy.*

Which of the following is the most likely cause of gastroesophageal reflux disease (GERD)?

(D) Decreased lower esophageal sphincter tone * Delayed gastric emptying, hiatal hernia, and decreased esophageal motility are all causes of GERD,*

The lower esophageal sphincter's pressures compared to stomach pressure are?

(D) Has a yield pressure greater than intragastric pressure *maintain a yield pressure greater than intragastric pressure to prevent reflux of stomach contents into the esophagus.*

Peristalsis of the small intestine... *contraction where, relaxation where?*

(D) Involves contraction of smooth muscle behind the food bolus and relaxation of smooth muscle in front of the bolus

macrolide antibiotic erythromycin: complains of nausea, intestinal cramping, and diarrhea. The side effects are from an antibiotic binding to receptors in the GI tract that recognize which gastrointestinal hormone?

(D) Motilin * Motilin is the gastrointestinal peptide hormone associated with the initiation of migrating motor complexes during the interdigestive period.*

Slow waves in small intestinal smooth muscle cells are

(D) Oscillating resting membrane potentials of GI smooth muscle *The slow waves bring the membrane potential toward or to threshold, but are not themselves action potentials. If the membrane potential is brought to threshold by a slow wave, the action potentials occur, followed by contraction.*

Which of the following best describes small intestinal motility initiation?

(E) Contractile activity is initiated in response to bowel wall distention.

Which of the following can occur without brain stem coordination?

(E) Gastric emptying *Gastric emptying of solids occurs when the contractile activity of the stomach reduces the size of the particles within the food sufficiently for them to pass through the pyloric sphincter*

The rate of gastric emptying would be relatively fast after the ingestion of a meal which has a:

(E) High water content *Isotonic, neutral pH, low caloric, liquid content has faster gastric emptying.*

Mass movements constitute an important intestinal event that lead to bowel movements. Mass movements cause what?

(E) Rectal distension *The rectum is empty of feces most of the time. When a mass movement forces feces into the rectum, the desire to defecate is initiated immediately.*

The motility pattern primarily responsible for the propulsion of chyme along the small intestine is...

(E) Segmentation *segmentation functions 1. Major: mixing chyme w/ digestive juices & exposing it to intestines wall. 2. Pushing chyme along intestines*

newborn does not pass meconium in the first 24 hr. Distended abdomen, vomitting. Hirschsprungs. An obstruction is most likely found in which portion of the gut?

(E) Sigmoid colon *any distal colon. ANY newborn w/o merconium w/in 24-48hr. check for hirschsprungs. *begins with the anus, which is always involved, and continues proximally for a variable distance*

PSNS stimulation increases G.I. motility and SNS stimulation inhibits G.I. motility. The ANS controls gut motility by changing what?

(E) Spike potential frequency *When a slow wave depolarizes sufficiently, it elicits spike potentials which are true action potentials. * *smooth waves in stomach--> contraction* *smooth wave in S.I. needs spike for contraction. *

What nervous system controls parastalysis?

. Peristalsis is contractile activity that is coordinated by the enteric nervous system [not the central nervous system (CNS)]

heartburn, burping, bad breath. dilated esophagus with narrowed LES. Which one of the pressure tracings was most likely taken at the lower esophageal sphincter of this patient before and after swallowing (indicated by arrow)?

. dilated esophagus with narrowed LES

healthy, eats big meal. the woman feels a strong urge to defecate, but manages to hold it. what happens to IAS, EAS, and rectum?

1. Internal anal spincter: RELAX 2. External anal spincter:Contract 3. Rectum: Contract *The defecation reflex (also called the rectosphincteric reflex) occurs when a mass movement forces feces into the rectum* *EAS is controlled voluntarily and can be contracted*

severs spinal cord at T6 . She devises a method to distend the rectum to initiate the rectosphincteric reflex. Rectal distension causes what to IAS, EAS, and rectum?

1. Internal anal spincter: RELAX 2. External anal spincter:RELAX 3. Rectum: Contract *EAS controlled by conscious brain, but she can't cause of the T6 thing*

Gastric emptying is tightly regulated to ensure that chyme enters the duodenum at an appropriate rate. What increases/ decreases to promote emptying in normal person 1. Tone of orad stomach 2. Segmentation contraction in small inestines 3. Tone of pyloric sphincter.

1. Tone of orad stomach: INCREASE 2. Segmentation contraction in small intestines: DECREASE 3. Tone of pyloric sphincter: DECREASE

Small intestine functions that don't need extrinsic innervation include...

1. stomach emptying 2. mixing and propulsion in small intestines

ANSWER for dilated esophagus with narrowed LES

Achalasia :(LES) fails to relax during swallowing. food can't leave esophagus for stomach (dilates) Trace C shows a high, positive pressure that fails to decrease after swallowing, which is indicative of achalasia

The basic electrical rhythm or slow waves recorded from intestinal smooth muscle:

B) Is synonymous with generator potentials (C) Varies in rate in different regions of the gastrointestinal system

vomiting center is in medulla. What happens to LES, USE, abdominal muscles, and diaphragm during?

Both sphincters relax, both muscles (abs & diaphragm) contract

what Serves as lubricant in gastrointestinal tract?

C) Mucin

CF-Mucus becomes thick and sticky. A primary disruption in the transfer of which ion across cell membranes occurs in CF leading to decreased secretion of fluid?

Chloride *abnormal chloride ion transport on the apical surface of epithelial cells in exocrine gland tissues. The CF transmembrane regulator (CFTR) protein functions both as a cyclic AMP-regulated Cl- channel *

Which of the following is the primary genesis of LES pressure in adults?

D) Myogenic properties of LES smooth muscle

Which stimulus is most important for the regulation of emptying of the intestine during the inter-digestive period?

E) Motilin *Motilin, a hormone released from the small intestine, increases the strength of the migrating motor complex (MMC) and may be responsible for initiating it*

sympathetics effect on parastalysis

Sympathetic adrenergic substances will also inhibit motor activity.

manometric recordings from a patient before and after pelvic floor training. Z=External anal sphincter. What is X?

The internal anal sphincter relaxes when the rectum is stretched, as indicated by repeated decreases in pressure following inflation of the rectal balloon.

Which line is for LES w/ achalasia? Answer

Trace B could represent the lower esophageal sphincter (LES) in a patient with achalasia

Answer for normal mid thoracic levels

Trace C shows a basal subatmospheric pressure with a positive pressure wave cause by passage of the food bolus

what line is normal LES? w/ answer

Trace D depicts normal operation of the LES.

factors that promote gastric emptying

a) decreased compliance of the stomach, (b) relaxation of the pylorus (c) an absence of segmentation contractions in the small bowel.

what elicited by stomach contractions?

elicited by reflexes initiated by antral distention and by gastrin.

yo, what's the corpus?

just another name for body, fam.

yo, what's the orad??

orad stomach (fundus and corpus)

At which location are smooth muscle contractions most likely to have the highest frequency in the diagrams shown?

the duodenum is most likely to have the highest frequency of smooth muscle contractions.