chap 13 - GI tract Flashcards
GI tract includes
oropharynx (mouth, salivary glands, pharynx)
alimentary tract (esophagus, stomach, small and large intestines, anus)
pancreaticobiliary tract (liver, gallbladder, bile ducts, and pancreas)
function of the GI tract
- digestion
- motility
- secretion
- absorption
- storage and elimination
microanatomy of GI trat wall
have some endocrine cells that secrete hormones throughout these walls
- mucosa
- submucosa
- muscularis propria
bacteria in GI tract
majority found in the large intestine
- facilitate the digestion of certain carbohydrates
- break down fibers (the body doesn’t make an enzyme that can)
- influence development and responsiveness of GI immune system
- metabolize certain drugs to active metabolites = so the drugs don’t harm our bodies
- produce nutrients such as folate and vitamin K
viral enterists
viral = virus -itis= inflammation, enteric = gut
- also known as intestinal flu or stomach flu
most frequent and serious problems of the GI tract
constipation, diarrhea, viral enteritis, diverticulosis, GERD
signs and symptoms of GI disorder
anorexia, altered motility, vomiting, nausea, constipation, diarrhea, retching, dysphagia, bleeding, lack of GI movement, hematemesis, melena
anorexia
loss of appetite
altered motility
going the wrong way (vomiting)
nausea
a subjective experience associated with a number of conditions
retching
nonproductive vomiting
dysphagia
difficulty swallowing
hematemesis
vomiting blood
melena
black tarry stool
- bleeding goes through all of the GI tract and is metabolized by bacteria which causes the change in appearance
upper GI bleeding
stomach and above
- hematemesis and melena
lower GI bleeding
small and large intestines
- hematochezia
occult fecal blood
blood in stool not noticed by individuals
tests of GI tract
gastric analysis - measurement of stomach acid
tests
tests on gastrointestinal contents, blood, and urine
- evaluate absorption of GI tract
fecal culture - looking at the bacteria that is present
endoscopy, sigmoidoscopy, colonoscopy
radiologic techniques - upper GI series, barium enema, CT scan
genetic/developmental diseases
usually due to embryonic malformations
- typically surgically correctable
examples: congenital pyloric stenosis, hirschsprung disease, hernias
congenital pyloric stenosis
narrowing of outlet of distal stomach resulting from hypertrophy of pyloric muscle
- cause is unknown
projectile vomiting after feeding begins 2 to 4 weeks after birth
- occurs almost exclusively in boys
- pyloric sphincter (in the stomach), stenosis = narrowing
hirschsprung disease
lack of ganglion cells in rectum results in defects bowel movement and megacolon - problem during development
- don’t develop the parasympathetic nervous system in the digestive system “rest and digest”
- suspected in infants with chronic constipation and distended abdomen
- requires surgical removal of aganglionic segment and reattachment of normal bowl
- not able to have a bowel movement = progresses to megacolon ( a huge colon, the undigested food matter stays in the colon cause it has no way of exiting)
hernias
bulging of organ or tissue through an abdominal opening
- named based on where they are located
if trapped, may get ischemic and infarct (due to decreased blood flow)
types: inguinal, hiatal, epigastric and umbilical
inguinal hernia
inguinal canal, near the groin area, primarily found in males
- outpouching of abdominal content into groin
- danger of bowel strangulation
surgical repair recommended before complications occur
hiatal hernia
more common with age because the abdominal muscles get weak with age
epigastric and umbilical hernia
found in infants
reflux esophagitis
inflammation of the esophagus, main job is to get the bolus of food into the stomach
can present with:
- dysphagia
- pain
- bleeding
- regurgitation of food into the trachea
- choking and coughing
types of reflux esophagitis
gastroesophageal reflux disease and laryngopharyngeal reflex
predisposing factors of reflux esophagitis
obesity, diet, bulimia, age (the spincter is less tight as you age), alcohol (loosens the sphincter), pregnancy (baby pushes on everything), laying down right after eating
reflux esophagitis is a risk factor for
acidity can break down and harm the esophagus
persistent severe reflex can lead to
barrett’s esophagus
- metaplasia – dysplasia => esophageal cancer
GERD vs. heartburn
GERD = reflux more than two times a week
heartburn is more acute
treatment of GERD
avoid foods that increase acidic reflux
medications that reduce acid production
- proton pump inhibitors = less hydrochloric acid, the pH goes up a little bit, less irritation to the esophagus
avoid lying down after eating
gastritis
Acute injury to gastric mucosa caused by agents that compromise the protective mucous barrier lying over the epithelial cells
Inflammation of the stomach
Causes lesions in the protective mucus that lines the stomach
May be associated with bleeding
symptoms:
- nausea
- vomiting
- epigastric pain
types of gastritis
acute and chronic
acute gastritis
- non steroidal anti inflammatories
- alcohol
chronic gastritis
autoimmune - Parietal cells - make the hydrochloric acid
- Helicobacter Pylori - bacteria that infects the stomach and can lead to chronic gastritis
helicobacter pylori
Most prevalent infectious agent worldwide
Infections More Frequent With Age - we produce less hydrochloric acid
Adapts to low pH of stomach - the pH level kills bacteria and helps to breakdown food
Testing
Antibodies detected in blood
Breath test
Stomach biopsy - endoscopy
Risk Factor for:
Ulcer - peptic ulcer just means an increase in the acid that causes irritation
Stomach cancer
peptic ulcer disease
A break or ulceration in the protective mucosal lining of the lower esophagus, stomach, or duodenum
Leading cause?
H. Pylori
symptoms of peptic ulcer disease
- Nausea
- Vomiting
- Gnawing or burning upper-abdominal pain
- Weight loss with decreased caloric intake
complications of peptic ulcer disease
- Internal bleeding
- Anemia (what kind?) iron-deficiency anemia
- Penetration into the pancreas: acute pancreatitis
- Perforation leading to infection, peritonitis
treatments for peptic ulcer disease
antibiotics
revolves around:
- Decreasing acid secretion
- Eliminating cofactors that led to development of ulcers - test for h. Pylori, if not there then what else could have caused it? NSAIDS taken on an empty stomach?
- Recurrences are common
- Some patients require surgical intervention
malabsorption
Failure to digest and/or absorb food
Caused by disease processes that impair enzyme activity and absorption of nutrients across the gastrointestinal epithelium
potential causes of malabsorption
Lactase deficiency
Inflammatory bowel disease
Pancreatic insufficiency
Pancreatic Enzymes
Bile salt deficiency
Celiac Disease
lactose intolerance
malabsorption
- Deficiency of lactase - enzyme that breaks down lactose
- Needs to be broken down into galactose and glucose and then those can be absorbed into the GI tract
- Brush boarder enzyme - right on the microvilli of the intestine
- Lactose stays and then moves into the large intestine → the bacteria will metabolize the lactose and ferment it which draws water into the large intestine which leads to diarrhea
- Symptoms: bloating, diarrhea, GI tract upset
- Treatment? Cut out dairy products (not the best option), oral enzyme supplements, or you can buy milk products meant for those who are lactose intolerant
celiac disease
malabsorption
- Autoimmune disease
- Allergy to gluten – Gluten? Protein that plants use (found in wheat, barley, and rye)
- Affect villus of small intestine
Symptoms
- Abdominal pain, bloating, gas
- Fat in stool - not absorbing the fat so it stays in the lumen
- Weight loss
- Malnutrition
- Constipation
- Treatment? Cut out gluten
enterocolitis
inflammatory
Causes
- Pathogens
- Virus
Rotavirus = children
Norovirus = adults
Bacteria= less common, more severe
E. coli
Salmonella
Campylobacter
Can happen from food contamination, not washing your hands after handling meat, etc.
Symptoms
Diarrhea
Vomiting
What someone might call the stomach flu
Leads to diarrhea = increase in volume of stool or frequency of defecation (3x/day)
2nd leading cause of death in children under 5
enterocolitis
inflammatory
Causes
- Pathogens
- Virus
- Rotavirus = children
- Norovirus = adults
- Bacteria= less common, more severe
- E. coli
- Salmonella
- Campylobacter
- Can happen from food contamination, not washing your hands after handling meat, etc.
Symptoms
- Diarrhea
- Vomiting
- What someone might call the stomach flu
- Leads to diarrhea = increase in volume of stool or frequency of defecation (3x/day)
- 2nd leading cause of death in children under 5
appendicitis
- Appendix: hangs of the beginning of the large intestine, kind of part of the immune system, collection of white blood cells
- More common in teenagers and young adults
- Inflammation of the appendix
- Medical Emergency
- If it bursts all the bacteria of the large intestine is released into the abdominal cavity and can lead to sepsis - Possible causes
- Infection,Obstruction
Typical Presentation - Right Lower Quadrant Pain
- Nausea
- Vomiting
- Fever
Most serious complication is peritonitis - inflammation of the peritoneum (the membrane that lines the abdominal cavity)
inflammatory bowel diseases
crohn’s disease and ulcerative colitis
characteristics of inflammatory bowel diseases
- Episodic bloody diarrhea
- Crampy abdominal pain
- Inappropriate immune response - the immune system is causing the inflammation but it is not considered to be autoimmune
- Family History
- Peak Age 15-30
- Involvement of extraintestinal tissues - tissues that are outside of the small and large intestine
treatment of inflammatory bowel diseases
Anti-inflammatories
Decrease activity of immune system
Resection - last resort
crohn’s disease
Patchy - patches of inflammation not a whole segment
Mouth to Anus
Transmural = across the GI tract – the mucosa, submucosa, etc.
Risk Factors
Caucasian
Female
Smokers
ulcerative colitis
Limited to?
Mucosa only - the inflammation does not go across the whole wall of the intestine
Colitis = inflammation of the colon, only in the colon
disturbances of colon and anus: diverticulosis and diverticulosis
- Small Pouches That Push out in weak spots in colon wall - outpouching
- Found almost exclusively in sigmoid colon
- Diverticulosis usually asymptomatic
- If It Becomes Inflamed, diverticulitis
- inflammation of diverticulosis - occurs mostly in the sigmoid colon
Complications - Pain
- Bleeding Abscess
- Perforation
periotinitis
Inflammation of the peritoneum - membrane that lines the abdominal cavity
Types
Infectious
usually due to bacteria from bowel due to perforation
Sterile
due to chemical irritation as when enzymes spill on peritoneum
Could be from an ulcer that drips enzymes or chemicals from other organs onto the peritoneum
Once healed, may produce adhesions - scar tissue on the intestine, adhesions don’t allow the small intestines to slide against each other as much, lack of movement during digestion can become dangerous
infectious peritonitis
usually due to bacteria from bowel due to perforation
sterile periotonitis
due to chemical irritation as when enzymes spill on peritoneum
Could be from an ulcer that drips enzymes or chemicals from other organs onto the peritoneum
neoplastic diseases
GI tract cancers include cancers of the:
Esophagus
Stomach
Small intestine
Colon
Anus
Colon cancer accounts for the majority of GI tract cancers
Typically aren’t found till stage four
esophageal carcinoma
Arise From Epithelial - the epithelium that lines the esophagus
Risk Factors:
Tobacco use
Alcohol use
GERD
Poor Prognosis
Tends to invade & metastasize early - and you don’t catch it in time, there isn’t a screening test for esophageal cancer
May present with dysphagia but this would be caught later
gastric carcinoma
Worldwide as deadly as lung cancer (#1 in U.S)
Epithelial tissue lining the stomach
Risk factors
H. pylori & chronic gastritis
Diet high in smoked, pickled, or salt-preserved food
Gastric cancer is highly prevalent in Japan because their diets are high in these food
Diet low in fresh fruit & vegetables
Usually asymptomatic until advanced
neoplasms of the colon and anus
Tumors of small bowel are uncommon
Most are premalignant
Takes years to become fully malignant
Most colon cancers are adenocarcinomas
Make and release mucus
One of the most curable cancers if detected early
colon cancer
Begins With Polyps On The Lining Of The colon
Polyps are pre-malignant
treatment Includes Radiation,chemotherapy, or surgery
Survival Rates Vary Depending On Age, treatment response, stage of cancer diagnosis
Risk Factors
Age
Family History
History of Polyps
High intake red meat
IBD
Manifestations
Bleeding
Blood in stool
Altered bowel habits
Diarrhea; constipation; or narrow, pencil-shaped stools
Iron-deficiency anemia
Diagnosis requires histologic confirmation
screening for colon cancer
Occult blood test
Not very sensitive but used over long periods of time has proven to be beneficial
Colonoscopy
Can reduce death rate by about 60%
Recommended for those over 50
Cologuard test
Detects genetic abnormalities in colonic epithelial cells shed in the stool
organ failure
Failure of absorption process can be tolerated for a number of days
Severe vomiting or diarrhea may prove fatal
Most susceptible?
Serious morbidity results from complications of disease process rather than from alterations of digestion and absorption
Example, blood loss
Surgical resection of large parts of the gut can be fairly well tolerated
Requires change in food consumption
Tube feedings can provide calories and nutrients
Defecation can be mechanically circumvented with ileostomy or colostomy
