Intro to Gastrointestinal System

Hiatal hernia

Heartburn sx and reduced breath sounds to lung with “gurgling”

Intake, breakdown, absorption, clearance

GI System goal is

A) __ of food

B) __ of food

C) __ of water and nutrients of food

D) __ of waste products

Mouth, tongue, parotid, sublingual, submandibular

Esophagus, liver, gallbladder, stomach, pancreas, spleen

Duodenum, jejunum, ileum, transverse colon, descending colon, ascending colon, cecum, sigmoid colon, rectum, appendix

Sphincters

Circular muscle rings with resting tone normally closed until detecting signal to relax

Chyme

Sphincters

Regulate directional movement of __ through GI tract

Upper esophageal sphincter

GI muscle between pharynx and larynx

Lower esophageal sphincter

GI muscle between esophagus and stomach

Hiatus, closed, reflux

Lower esophageal sphincter

• Combines with __ to keep esophagus “__” at baseline

• Prevents __ of GI contents

Pyloric sphincter

GI muscle between stomach and small bowel

Ileocecal sphincter

GI muscle between small bowel and colon

Internal anal sphincter

GI muscle between rectum and anus, with involuntary smooth muscle

External anal sphincter

GI muscle between rectum and anus with voluntary skeletal muscle

Proteins, glucose, metabolism, excretion, bile

Roles of Liver

• Production of __ (i.e. albumin, clotting/anti-clotting factors)

• __ management

• __ of substances

• waste __

• __ production

Gallbladder

Region of bile storage and can become inflamed

Digestive, glucose, inflammation, obstruction

Roles of Pancreas

• Secretes __ enzymes into GI tract

• __ management

• Prone to ___, tract __, cancer, diabetes

Large pancreatic head tumor, stone in common bile duct, and sphincter of oddi stenosis

Which are the 3 common causes of bile “backing up” into liver and jaundice?

Choledocholithiasis

Stone in common bile duct

Myenteric plexus

Neurological structure responsible for intrinsic regulation of GI muscle contractions

myenteric plexus

From epithelia

Stretch out, volumes, surface area

• Why does stomach have lots of folds?

  • Easier to __ __ and expand __ after eating/drinking

• Why does small intestine have villi and crypts?

  • Increased __ __ → Increased absorption

Absorption, osms, diarrhea, malnutrition, celiac

What happens if villi atrophy or are blunted?

• Decreased surface area = Decreased __

• Extra __ in GI tract lead to __ and __ (sx)

• Ex: Excess gluten consumption from a __ disease patient

Celiac disease

Enteric nervous system

Coordinated relaxation and contraction to mix and move chyme through GI tract via reflexes

Emesis

Action of __ moves chyme from GI tract back out of mouth

Oral phase

• Tongue pushes bolus into pharynx

• Stretch receptor signal to medulla and initiate reflex

(swallowing phases)

Pharyngeal phase

• Soft palate raised, epiglottis covers airway

• UES relaxes, Peristaltic wave in pharynx

(swallowing phases)

Esophageal phase

• Peristaltic wave moves bolus through esophagus

• LES relaxes

(swallowing phases)

Achalasia

Dysfunction of myenteric nerve plexus in esophagus and LES

Idiopathic, Chagas, relax

Achalasia

• __pathic and associated with __ disease

• Lack of signal to __ from the plexus

Segmentation, peristalsis

• __ is the act of mixing chyme

• __ is the act of moving chyme from stomach to small bowel

Vomiting

Anti-peristalsis where small bowel contents travel back up stomach

Breath, UES, glottis, posterior nares, abdominal, LES

Vomiting Steps

• (1) Taking a deep __

• (2) larynx raises and opens the __

• (3) __ closes to protect lungs

• (4) Soft palate raises to close the __ __

• (5) Diaphragm further contracts and __ muscles contract to squeeze stomach

• (6) __ relaxes = Vomitus expelled

Ileus

Post-traumatic inflammation of ileum, often from abdominal surgery

Stunned, sympathetic, peptides, diabetic neuropathy

In ileus

• “__ bowels”

• Increase in inhibitory __ stimulation and inhibitory __

• Gastroparesis = Can result from __ __ (neuro pathology)

GERD

Pressure in stomach greater than pressure of LES

Pyloric stenosis

Obstruction with non-bilious emesis of partially digested food

Nausea

Conscious recognition of excitation in medulla near/in vomiting center

Medulla, chemical, distension, vestibular, histamine, chemoreceptor trigger, cerebral inputs

Nausea caused by input to vomiting center in the __ (brain)

• Impulses from GI tract - __ irritation or __

• Motion sickness - __ system muscarinic and __ Rs

• Direct stimulation of __ __ zone by opioids, chemo drugs, 5-HT

• __ __ - sight, sounds, smells, thoughts