Chapter 36 - Alterations in Digestive Function Flashcards
How does the digestive tract structure vary from mouth to anus?
it doesn’t, it is all the same
Name the 4 layers of the digestive tract from deep to superficial:
- mucosa (innermost)
- submucosa
- muscularis externa
- serosa (outer layer)
What does the mucus layer protect?
mucosa (epithelial layer)
How many mucus layers does the small intestine have?
1
How many mucus layers does the large intestine have?
2; an inner and outer
How do structural and neural GI tract disorders disrupt digestion?
obstruction, slowing, or accelerating contents
How do inflammatory and ulcerative GI tract disorders disrupt digestion?
disrupt secretion, motility, absorption
How do disorders of accessory organs disrupt digestion?
by altering metabolism
What are the accessory digestive organs?
liver, gallbladder, pancreas
What is the Greek word for vomiting?
Emesis
Vomiting Definition
forceful emptying of stomach or intestinal contents through the mouth
Where is the vomiting centre in the brain?
medulla oblongata
What is retching?
a muscular event of vomiting without vomitus expulsion
What is projectile vomiting?
spontaneous vomiting that does not follow nausea or retching
What causes projectile vomiting?
direct stimulation of the vomiting centre in the medulla oblongata
Abdominal Distention
swelling of the abdomen
Vomiting usually follows _____ or ______ of the stomach or duodenum.
pain or distension
When vomiting is initiated, it starts with a deep __________ and the closure of the ______.
inhalation; glottis
What creates pressure from stomach to throat before vomiting?
abdominal muscles
Which parts of the GI tract spasm and force chyme into the esophagus?
duodenum (sm. intestine) and antrum (stomach)
When vomiting is initiated which esophageal sphincter stays closed so the contents can’t enter the mouth?
upper esophageal sphincter
What returns contents to the stomach when vomiting is initiated?
relaxation of the abdominal muscles
The process of forcing intestinal contents up and down is repeated several times until the ____________ nervous system relaxes both esophageal sphincters.
parasympathetic
How is stomach chyme forced out of the mouth?
contraction of the abdominal muscles to force the diaphragm high into the thorax
What is constipation?
difficult or infrequent defecation
Why is constipation individually determined?
people have different pooping schedules ie. some are 1-3x daily and others may be once a week
Primary Constipation
impaired, infrequent, straining colonic movement
Secondary Constipation
due to altered neural pathways that delay colon transit time
Which drugs inhibit bowel movement?
opiates (mainly codeine)
A notable change in constipation can indicate:
colorectal cancer
Straining to poop may cause…
hemorrhoids
How are hemorrhoids/constipation diagnosed?
-sphincter tone assessment
-detection of anal lesions
-colonoscopy
3 Ways to Treat Constipation:
- over the counter laxatives (RestoraLAX)
- enema
- colectomy
Enemas are used to establish bowel _______, and should not be used habitually
routine
Colectomy
surgical removal of part of the colon
Diarrhea
loose watery stool
Acute diarrhea lasts ____ hours or less
24
How long does persistent diarrhea last?
14-28 days
How long does chronic diarrhea last?
longer than 4 weeks
Diarrhea poses high morbidity/mortality rates for children under ___
5
Osmotic diarrhea occurs when…
non-absorbable substances in the intestine draw excess water into the intestine
Secretory diarrhea occurs with…
excessive mucosal secretion of fluid and electrolytes
What are two causes of secretory diarrhea?
viruses and bacterial toxins
Rotavirus is a ____ virus that causes _______
RNA; enteritis
Enteritis
inflammation of the intestinal system
Motility diarrhea occurs when…
excessive motility decreases transit time and reabsorbtion
Motility diarrhea occurs with ________ bypass of intestinal area
surgical
How is diarrhea treated?
-fluid and electrolyte restoration
-anti-motility and water absorbent medication
Abdominal pain can be caused by ________, __________, or _________ factors
mechanical, inflammatory, or ischemic
With abdominal pain, what activates pain receptors?
stretching or distention of abdominal organs
Parietal pain arises from the parietal peritoneum which is the ________ membrane
outer
Parietal pain is ________ and intense
localized
Visceral pain arises from distention, inflammation, or ischemia of __________ _______
abdominal organs
Visceral pain is ______ _______ and ________
poorly localized and radiating
Bleeding in which 3 areas is considered ‘upper’ gastro-intestinal bleeding?
esophagus, stomach, duodenum
Upper GI bleeding is which colour and why?
Bright red due to effects of stomach acids
What causes upper GI bleeding?
-peptic ulcers
-tearing of esophageal gastric junction caused by severe retching
Bleeding in which 4 areas is considered ‘lower’ gastro-intestinal bleeding?
jejunum, ileum, colon, rectum
What are 3 causes of lower GI bleeding?
-polyps
-inflammatory disease
-hemorrhoids
Occult bleeding is not obvious and occurs due to slow ______ blood loss
chronic
Occult bleeding results in an ______ deficiency (anemia)
iron
GI bleeding presents as blood in ______, ______ ______ reduction, compensating _________, or ______ loss
stool; blood pressure; tachycardia; vision
Why does vision loss occur sometimes with GI bleeding?
the blood vessels in the eye are the smallest so they are the first to suffer
Dysphagia
difficulty swallowing
Mechanical Obstruction of Esophagus
obstruction in esophageal wall due to tumour or herniations
Functional dysphagia occurs due to a ______/_______ disorder that interferes with swallowing
neural/muscular
Achalasia is a rare form of _________
dysphagia
Achalasia occurs when the ______ muscle neurons of the middle/lower esophagus are attacked by ____________
smooth; immune response
Achalasia results in altered ________, failure of the _____ to relax, cough and aspiration
peristalsis; LES (lower esophageal sphincter)
What does GERD stand for?
Gastroesophageal Reflux Disease
Esophagitis may be caused by…
reflux of acid (pepsin) or bile salts into the esophagus
GERD is caused by a)_____ b) ________
a) LES abnormality (lower resting tone)
b) Delayed gastric emptying of chyme
The severity of damage on the esophagus due to GERD depends on the __________ and ________ of reflux
composition and duration
Prolonged acidic chyme exposure can lead to ______ injury
mucosal
Persistent GERD can lead to…
fibrosis thickening and precancerous lesions
How is GERD diagnosed? (2)
-esophageal endoscopy
-tissue biopsy
GERD is treated using laparoscopic fundoplication meaning…
surgical tightening of the junction between the esophagus and stomach to prevent acid reflux
What is a hiatal hernia?
protrusion of the superior aspect of the stomach through the diaphragm hiatal into the thorax
A sliding hiatal hernia occurs when the stomach moves into the thorax _______ the esophageal hiatus
through
A paraesophageal hiatal hernia occurs when the stomach moves _____ the thorax ________ the esophageal hiatus
into; alongside
What is an emergent risk of a hernia?
strangulation
How are hiatal hernias diagnosed?
radiology with barium swallow
How are hiatal hernias treated? (2)
-sleeping with head up
-laparoscopic fundoplication
What is an intestinal obstruction (IO)?
any condition that prevents the normal flow of chyme through the intestinal lumen
What is a paralytic ileus (PI)?
a functional obstruction resulting from the failure of intestinal motility due to dysfunctional neural activity post op
A large bowel obstruction (LBO) is ______ common but often related to _______
less; cancer
What are the signs an symptoms of a Large Bowel Obstruction?
abdominal distension and vomiting
Small bowel obstructions (SBO) are caused by ______________ that lead to distensions
post-operative adhesions
SBO results in 5 things. Which of these are true?
A) Constipation from decreased motility
B) Distension that impairs absorption
C) Sepsis due to leakage of pathogens
D) Blood in stool
E) Increased secretion leading to gas, fluid, and solute accumulation
F) Fluid movement into the lumen
G) The lumen becoming acidic
B, C, E, F, G
With a SBO, what is the result of systemic ECF moving into the lumen? (3)
dehydration, tachycardia, possible shock
Sepsis from a SBO leads to an ________ response that may result in remote organ failure.
immune
Gastritis
inflammatory disorder of the gastric mucosa
Acute Gastritis
erosion of the protective stomach mucosal barrier
What causes Acute Gastritis? (2)
Helicobacter pylori and NSAIDs
NSAIDs
a drug that inhibits prostaglandin synthesis
What do prostaglandins do?
stimulate goblet cells to secrete mucus
What does H. pylori do?
burrows into mucus layer and disrupts mucosal layer function while triggering an immune response
Gastritis symptoms:
-pain
-vomiting