GI to Appendicitis Flashcards
4 main layers of intestine
1) Serosa
2) Muscularis externa (composed of longitudinal and circular muscle)
3) Submucosa
4) Mucosa (composed of epithelium, lamina propria, and muscularis mucosa)
Fx of submucosa
The submucosa is the layer of dense irregular connective tissue or loose connective tissue that supports the mucosa, as well as joins the mucosa to the bulk of underlying smooth muscle.
Fx of mucosa
The mucosa is the innermost tissue layer of the small intestines, and is a mucous membrane that secretes digestive enzymes and hormones. The intestinal villi are part of the mucosa.
Review structural organization of alimentary canal
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What is diverticular disease?
How does its incidence relate to age?
- Multiple diverticula (an “out-pouching” of the wall of the digestive tract – pouching away from the lumen
- Prevalence = 5-10% of individuals > 45yrs
• 80% > 85yrs
*Strong correlation between age and prevalence!!
Etiology/risks for diverticular disease?
1) Poor DIET (low fibre) → constipation causes accumulation in lumen, pressure on lumen increases (which has already been weakened by process of aging), causing out-pouchings
2) With AGE, diet becomes imbalanced because of changed dentition, cannot be hard things, degenerative changes of tissue
3) INACTIVITY – activity enhances perfusion of GI tract
4) POOR BOWEL HABITS (constipation) – does not as regularly evacuate bowels will contribute to constipation
Patho of Diverticular Disease
- Normal weak points for vessel entry (Are entry points for blood vessels entering wall of intestines…the openings by which these enter are usually tight, will loosen with age)
- Intraluminal pressure inc → mucosa herniates through muscularis externa → bowel protrusion (wall pushes out through itself)
Where (in the GI tract) do the out-pouchings in diverticular disease usually occur? Just one or multiple?
Mostly within sigmoid colon (but can occur in most places in digestive tract) – mostly in large intestine because this is where problem of constipation is
• Multiple sites (usually have several outpouchings…not one single)
2 types of diverticular disease?
1) Diverticulosis
2) Diverticulitis
Difference between two types of diverticular disease?
1) Diverticulosis = non-inflamed out-pouchings (d/t injury or infection)
- Asymptomatic
2) Diverticulitis = inflamed out-pouchings
- Symptomatic
Symptoms of diverticulitis?
o Dull pain, nausea, vomiting, low grade fever
o Aching type of pain
Tx of diverticular disease?
- Address etiology/risks
* Address complications → sx for obstruction or perforation
Why does fever occur in absence of infection?
Damaged cells produce endogenous pyrogens
rest of mechanism is the same
What is IBS?
What is the problem?
- GI Mobility disorder
- Almost everyone has some level of it (is spectrum)
- No obvious abnormality in structure or function, pathology unclear
Etiology of IBS?
- Unclear (but are risk factors)
* Linked to diet, stress, smoking, lactose intolerance
Why is smoking associated with IBS?
Smoking has series of noxious components that circulate within body, can cause intestinal cancers, etc….
What is thought to be the pathology of IBS?
Patho not apparent but are speculated ideas:
1) Malabsorption of fermentable CHO and polyols- suggests we have fermentable CHOs (ex: fructose) and polyols (sugar alcohols, ex: sorbitol) then when ingested by those with IBS, are not properly processed (in small intestine or stomach?) - in colon the bacteria process these sugars and produced gas → end up with flatulence → Gas distends the intestine, presents with pain
2) Altered CNS regulation of GI motor and sensory fx?
know CNS innervates digestive tract and is largely involved in regulating motility of the gut (also perfusion, secretion, etc.)…suggestion of theory is that there’s a problem either in CNS or where neurons meet digestive tract (such as synapse) that effects
3) Molecular signaling defect of serotonin
(is produced in mucosa of gut…thought that process of synthesis, release, storage, action, and/or degredation is defective
Functions of Serotonin:
1) Mediates motility in the gut
2) Involved in sensation/pain
3) Involved in secretion
4) Involved in perfusion (vasodilation/constriction)
What main pieces of evidence show that a seronin defect may be involved in IBS?
1) Site of synthesis - produced in mucosa
2) Serotonin action & IBS manifestations
- Fxs of serotonin very much linked to symptoms of IBS
- If serotonin is functioning normally, should not feel sensation/pain of peristalsis…IBS do
Symptoms of IBS
- Abdominal discomfort & pain
- Constipation &/or diarrhea – can occur in same person; depends on what person is eating (food is trigger for one of these issues)
- Flatulence, nausea
- Mucoid stool (with excessive mucous secretion)