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
How long does gastritis take to begin healing?
within a few days
Who does chronic gastritis occur in?
older adults
Chronic gastritis causes chronic ________ and mucosal _______
inflammation; atrophy
Chronic Non-Immune Gastritis = _______ gastritis
antral
Chronic Immune Gastritis = _____ gastritis
fundal (involves body and fundus)
What causes antral gastritis?
H. pylori
Antral gastritis involves high levels of ____ secretion that increases the risk for __________
HCl; duodenal ulcers
Fundal gastritis is caused by…
loss of T cell tolerance
What happens with Fundal gastritis?
loss of T cell tolerance causes gastric mucosa to be degenerated
What causes peptic ulcers? (2)
H. pylori and NSAIDs
Name the 3 types of peptic ulcers:
- duodenal
- gastric
- stress-related mucosal disease
What are the most frequent type of peptic ulcer?
duodenal ulcers
How are duodenal ulcers formed?
causative factors that cause acid and pepsin to penetrate the mucosal barrier
How does the host respond to duodenal ulcers?
T and B cells, neutrophils combat H. pylori which release cytokines that damage the gastric epithelium
Does H. pylori release a toxin?
yes, it causes apoptosis in epithelial cells
How common are gastric ulcers to duodenal ulcers?
1/4 as common
Where do gastric ulcers form?
gastric antrum (next to acid producing gastric body)
What is the defect that causes gastric ulcers?
increased permeability of the mucosal barrier to H+
What does HCl do?
convert pepsinogen to pepsin
Mucosa damaged by H+ in gastric ulcer formation produces ________
histamine
What does histamine stimulate?
HCl (and thus pepsin) production
Stress-related mucosal disease is an _____ form of peptic ulcers
acute
What 3 things are often accompanied by stress related mucosal disease?
- physiological stress
- illness
- major trauma
Where do ulcers from SRMD form?
multiple sites in stomach or duodenum
Ischemic Ulcers
develop within hours of events such as hemorrhage, heart failure, sepsis
Curling Ulcers
develop due to burn injury
Cushing Ulcers
develop due to brain trauma or surgery
The loss of the body’s ability to discriminate harmful pathogens from commensal microorganisms can activate the ________ system which produces pro-inflammatory _________ which destroy the intestinal epithelium
immune; cytokines
Commensal
one organism benefits and the other neither benefits or is harmed
What are the 3 inflammatory bowel diseases?
- ulcerative colitis
- Chron’s disease
- Irritable bowel syndrome
What is ulcerative colitis?
a chronic inflammatory disease that causes ulcers in the colonic mucosa
Where does ulcerative colitis begin? Where does it spread to?
begins in rectum and may extend to entire colon
With ulcerative colitis, small erosions turn into ulcers by means of _______
necrosis
With ulcerative colitis, which layer of the GI tract thickens to narrow the lumen, reducing transit time?
muscularis mucosa
Symptoms of ulcerative colitis:
-bleeding
-urge to defecate
-watery diarrhea (10-20/day) with blood and mucus
Are the symptoms of ulcerative colitis persistent?
no, there are periods of remission (bettering) and exacerbation (worsening)
How are ulcerative colitis and Chron’s disease diagnosed?
endoscopy and biopsies
How are ulcerative colitis and Chron’s disease treated?
-steroids
-medication
-surgery (severe cases)
What causes Chron’s disease?
unknown, it is an idiopathic disease
What part of the digestive tract does Chron’s disease affect?
anywhere from mouth to anus
With Chron’s disease, where does the inflammation begin?
intestinal submucosa
Chron’s disease either spreads _____________ or __________
discontinuous or transmural
Discontinuous Spread
“skip lesions” or discontinuous/patchy inflammation
Transmural Spread
across the entire wall of an organ (full length of bowel wall)
Where is the most common site of Chron’s disease?
ascending and transverse colon
Chron’s disease ulcers can produce _______ (fistulae) that extend the inflammation into the _________ tissue
fissures; lymphoid
_________ increases risk for severe Chron’s disease and a poor response to treatment
smoking
Fistulae
an abnormal opening or passage between two organs
With CD, where do fistulae form? (4)
- peri-anal area
- bladder
- rectum
- vagina
What is Irritable Bowel Syndrome (IBS)?
abdominal pain with altered bowel habits (alternating constipation and diarrhea)
What causes IBS?
unknown (idiopathic), no biomarkers for disease
Evidence leans toward altered gut ________ causing IBS
microflora (normal gut bacteria)
IBS is ___-___x more common in _____ with a higher prevalence in youth and middle age.
1.5-3x; women
IBS Symptoms
-lower abdominal pain
-discomfort
-bloating
IBS symptoms are usually relieved with __________
defecation
Does IBS interfere with sleep?
no
Is there a cure for IBS?
no
IBS treatment is ____________
individualized
What is appendicitis?
inflammation of the appendix
What does the appendix supposedly do?
lymphoid tissue body that is a “safe house” for commensal bacteria that repopulate the intestinal system
What is the most common surgical emergency of the abdomen?
appendicitis
Appendicitis usually occurs at age ____-____ but can occur at any age or not at all.
10-19 years
Symptoms of Appendicitis
-mild pain that increases to intense pain in a span of 3-4 hours
-nausea
-vomiting
How is appendicitis treated?
laparoscopic appendectomy
A hypothesis for the cause of appendicitis indicates that it becomes _________, which blocks drainage, increases pressure, and reduces blood flow causing it to become _________.
obstructed; hypoxic
Hypoxic appendix tissue turns into an ______ that promotes _________ invasion triggering an immune and inflammatory response.
ulcer; bacterial
Bacterial invasion of the appendix ulcer causes _________ to develop
gangrene
What are the four main disorders of the liver? (Hint: h______ e______, j_________, c________, viral h________)
- hepatic encephalitis
- jaundice
- cirrhosis
- viral hepatitis
Encephalopathy
brain disease that alters brain structure or function
What is hepatic encephalopathy?
a complex neurological syndrome that begins in the liver and is characterized by impaired behavioural, cognitive, motor function
What do biochemical alterations alter in hepatic encephalitis?
neurotransmission and brain function
Hepatic encephalitis results from a liver dysfunction where collateral vessels _______ blood around the liver into ________ circulation
shunt; systemic
Shunting hepatic blood into the systemic circulation allows _________ absorbed by the GI tract (usually for removal) to travel to the _______.
toxins; brain
What do toxins do to the brain? (3)
-alter energy metabolism
-interfere with neurotransmission
-cause edema
How does ammonia contribute to hepatic encephalitis?
it causes astrocytes to swell which alter the BBB and promote cerebral edema
What is another name for jaundice?
Icterus
What is jaundice?
yellowing pigmentation of the skin
What causes jaundice?
hyperbilirubinemia (↑ plasma bilirubin)
Bilirubin is a component of ___________ breakdown
hemoglobin (Hb)
Bilirubin is a waste product that is normally removed by the _______, thus jaundice indicates damage to this organ.
liver
Jaundice is characterized as either __________ or __________
obstructive or hemolytic
Obstructive Jaundice occurs when the ________________ becomes occluded by gall stones or a tumour
common bile duct
Obstructive jaundice results in bilirubin entering the blood stream after it is accumulated in the liver because it can’t flow to the _________
duodenum
Hemolytic jaundice occurs when large bilirubin amounts are produced from excessive ___________
hemolysis of RBCs
Darkened ________ will be noticeable several days before the onset of jaundice
urine
Jaundice development poses risk for ________ infections
bacterial
Which part of the skin yellows first?
the sclera of the eye
What is cirrhosis?
the irreversible fibrotic scarring of the liver in response to inflammation and tissue damage
What step is cirrhosis in the process of chronic liver diseases?
final step
The physiological hallmark of cirrhosis is the development of…
scar tissue
Cirrhosis obstructs _______ flow, producing ________, portal ____________, and cellular _________
blood; jaundice; hypertension; dysfunction
What disrupts liver regeneration after cirrhosis has occurred that leads to liver failure?
hypoxia (lead to necrosis, atrophy, then liver failure)
Cirrhosis is manifested by is _________ appearance and _______ texture upon palpation
cobbly; hard
What are the 3 types of cirrhosis?
- alcoholic
- non-alcoholic fatty liver disease
- biliary
Alcoholic cirrhosis occurs due to the toxic effects of alcohol or _______ alterations
immune
What is alcohol transformed into that activates hepatic stellate cells?
acetaldehyde
Hyper activation of stellate cells forms _________ that leads to fibrosis and scarring
collagen
Damage via alcoholic cirrhosis results in gut microbiota being _____________
translocated (movement)
Non-alcoholic fatty liver disease is characterized by an infiltration of hepatocytes with __________
triglycerides
Non-alcoholic fatty liver disease is associated with ________
obesity (high blood triglyceride and cholesterol levels)
Damage due to biliary cirrhosis begins in the ___________ rather than hepatocytes
bile ducts
Primary Biliary Cirrhosis is caused by…
chronic autoimmune liver disease (T cell and anti-mitochondrial antibodies)
Damage to the bile ducts by fibrosis from primary biliary cirrhosis leads to a bile duct ___________
obstruction
What causes secondary biliary cirrhosis?
obstruction of common bile duct via gallstones or tumours
What is viral hepatitis?
a common systemic disease that primarily affects the liver
How many types of hepatitis are there?
5 - A, B, C, D, E
What can all types of hepatitis cause?
jaundice
Hepatitis pathogens cause hepatic cell _________ and scarring
necrosis
What promotes further injury with hepatitis?
the immune response
What types of hepatitis are the most severe in terms of damage?
B (B has vaccine) and C (C has no vaccine)
Why does a co-infection of Hepatitis and HIV occur?
the virus’ share the same transmission route
How is hepatitis spread?
body fluids
Co-infection of HIV and Hep causes a rapid ___________
progression of the disease
How is hepatitis diagnosed?
presence of viral antibodies
How is hepatitis treated?
viral replication suppression drugs
___________ and ___________ are common gallbladder disorders
obstruction and inflammation
What are gallstones?
aggregates of bile that block the flow of bile in/out and lead to gallbladder inflammation
What is Cholelithasis?
gallstone formation
What is Cholecystitis?
gallbladder inflammation
What causes a pancreatic obstruction?
backup of pancreatic secretions
Pancreatic obstruction causes the release and activation of pancreatic ________ within ______ cells
enzymes; acinar
What is the result of enzyme release in the pancreas?
auto-digestion of cells and tissues that cause inflammation
Autodigestion causes ______ damage, n________, and _________ formation
vascular; necrosis; pseudocyst
Pseudocyst
walled off collections of pancreatic secretions
______ is the main cause of further pancreatic obstruction
alcohol
When acinar cells metabolize ethanol it creates…
toxic metabolites that release acinar digestive enzymes
Chronic alcohol effects destroy acinar cells and destroy tissue that is replaced with ________
fibrosis (scarring)
Scarring in the pancreas leads to pancreatic ______
cysts
How is pancreatic obstruction via alcohol treated?
alcohol cessation
Cancer of the esophagus can be ________ or _______________
carcinoma or adenocarcinoma
Where are adenocarcinomas initiated?
epithelial glandular cells
Where are carcinomas initiated?
epithelial squamous cells
Esophageal cancer causes _______ and _____ pain
dysphagia and chest pain
__________ combined with smoking or _______ tobacco increase risk for esophageal cancer
Alcohol; chewing
Gastric (stomach) cancer is associated with _________ and _____ or preserved foods
H. pylori; salty
How does salt contribute to gastric cancer?
enhances conversion of nitrates into carcinogenic nitrosamines
Pre-existing _____ are highly associated with colon ______________
polyps; adenocarcinomas
Colon and rectal cancer manifest as: (3)
-pain
-bloody stool
-change in bowel habits
Where can rectal carcinomas close to the anus spread to?
vagina or prostate
Cancer of the ______ accounts for the leading cause of worldwide cancer deaths
liver
Primary liver cancers are associated with chronic liver diseased caused by ______ or hep __
cirrhosis or hep B
Where do hepatocellular carcinomas arise from?
hepatocytes
Where do cholangiocellular carcinomas originate?
bile ducts
Cholangiocellular carcinomas are _____
rare
What ages are gallbladder cancers most common?
age 50-60
Is carcinoma or adenocarcinoma more common in the gallbladder?
adenocarcinoma
Where do gallbladder cancers metastasize to?
lymph vessels
Pancreatic cancer is the ______ leading cause of cancer death in Canada
fourth
___________ occurs in the ______ (gland type) part of the pancreas
adenocarcinomas; exocrine
