Laxatives: Uses and Considerations

What is the term for the evacuation of formed fecal material from the rectum?

Laxation (correct)
Osmosis
Catharsis
Purgation

Which of the following may occur if volume depletion is prominent due to habitual use of laxatives?

Secondary aldosteronism (correct)
Anemia
Hypothyroidism
Osteoporosis

What do catharsis and purgation refer to?

Evacuation of formed fecal material
Altering motility by stimulating contractions
Evacuation of unformed fecal material (correct)
Enhancing retention of intraluminal fluid

How do laxatives act to enhance retention of intraluminal fluid?

By decreasing net absorption of fluid (B) Signup and view all the answers

What is a potential effect of excessive loss of calcium in the stool due to laxative use?

Osteomalacia (B) Signup and view all the answers

When are laxatives employed according to the given text?

Before surgeries and procedures requiring an empty colon (A) Signup and view all the answers

What is the mechanism of action of osmotic laxatives?

Increase the activity of NO synthase and the biosynthesis of platelet-activating factor (D) Signup and view all the answers

How do semisynthetic celluloses like methylcellulose and calcium polycarbophil work as dietary fiber supplements?

Absorb water and increase faecal bulk (C) Signup and view all the answers

What effect does wheat bran have on stool weight and transit?

Increases stool weight and transit due to high lignin content (D) Signup and view all the answers

What is the main effect of magnesium-containing laxatives?

Lead to intraluminal fluid and electrolyte accumulation and increased intestinal motility (C) Signup and view all the answers

What happens when dietary fiber that is not fermented reaches the colon?

It increases stool bulk by attracting water (C) Signup and view all the answers

What is the mechanism of action of phosphate salts like sodium phosphate as laxatives?

<pre><code>Lead to intraluminal fluid and electrolyte accumulation and increased intestinal motility (B) </code></pre> Signup and view all the answers

What is the effect of fermentation of fiber in the colon?

Produces short-chain fatty acids that are trophic for colonic epithelium (B) Signup and view all the answers

What is the main effect of nondigestible sugars and alcohols like lactulose, sorbitol, and mannitol?

Resist intestinal disaccharidase activity and produce short-chain fatty acids (B) Signup and view all the answers

What do fruits and vegetables primarily contribute to stool transit?

Increased bacterial mass due to fermentation (B) Signup and view all the answers

What are the general considerations related to habitual use of laxatives?

Excessive loss of water and electrolytes, secondary aldosteronism, steatorrhea, protein-losing enteropathy with hypoalbuminemia, and osteomalacia due to excessive loss of calcium in the stool. Signup and view all the answers

What is the distinction between laxation and catharsis or purgation?

Laxation refers to the evacuation of formed fecal material from the rectum, while catharsis or purgation is the evacuation of unformed, usually watery fecal material from the entire colon. Signup and view all the answers

How do laxatives act to enhance retention of intraluminal fluid?

Laxatives act by enhancing retention of intraluminal fluid through hydrophilic or osmotic mechanisms. Signup and view all the answers

What is the main effect of the commonly used laxatives?

The commonly used laxatives promote laxation by enhancing the retention of intraluminal fluid and altering motility. Signup and view all the answers

When are laxatives employed before surgical, radiological, and endoscopic procedures?

Laxatives are employed before surgical, radiological, and endoscopic procedures where an empty colon is desirable. Signup and view all the answers

What are the potential complications of laxative use?

Excessive loss of water and electrolytes, secondary aldosteronism, steatorrhea, protein-losing enteropathy with hypoalbuminemia, and osteomalacia due to excessive loss of calcium in the stool. Signup and view all the answers

What is the main effect of dietary fiber supplements like semisynthetic celluloses (e.g., methylcellulose and calcium polycarbophil)?

They absorb water and increase faecal bulk. Signup and view all the answers

What is the main effect of magnesium-containing laxatives?

They stimulate the release of cholecystokinin, leading to intraluminal fluid and electrolyte accumulation, and increased intestinal motility. Signup and view all the answers

What is the role of platelet-activating factor in the gut?

It is a phospholipid proinflammatory mediator that stimulates colonic secretion and GI motility. Signup and view all the answers

What is the effect of fermentation of fiber in the colon?

It produces short-chain fatty acids that are trophic for colonic epithelium and increases bacterial mass. Signup and view all the answers

What is the main effect of dietary fiber that is not fermented?

It attracts water and increases stool bulk. Signup and view all the answers

What is the effect of nondigestible sugars and alcohols like lactulose, sorbitol, and mannitol?

They are hydrolyzed in the colon to short-chain fatty acids. Signup and view all the answers

How do osmotically active laxatives, such as magnesium-containing laxatives, work?

They lead to intraluminal fluid and electrolyte accumulation and increased intestinal motility. Signup and view all the answers

What is the main effect of wheat bran as a dietary fiber supplement?

It is most effective at increasing stool weight and transit. Signup and view all the answers

What is the mechanism of action of phosphate salts like sodium phosphate as laxatives?

They are better absorbed than magnesium salts, hence higher doses are required for their cathartic effect. Signup and view all the answers

What is the main effect of psyllium husk as a dietary fiber supplement?

It leads to an increase in colonic bacterial mass. Signup and view all the answers

Laxatives: Uses and Considerations

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Questions and Answers

What is the term for the evacuation of formed fecal material from the rectum?

Which of the following may occur if volume depletion is prominent due to habitual use of laxatives?

What do catharsis and purgation refer to?

How do laxatives act to enhance retention of intraluminal fluid?

What is a potential effect of excessive loss of calcium in the stool due to laxative use?

When are laxatives employed according to the given text?

What is the mechanism of action of osmotic laxatives?

How do semisynthetic celluloses like methylcellulose and calcium polycarbophil work as dietary fiber supplements?

What effect does wheat bran have on stool weight and transit?

What is the main effect of magnesium-containing laxatives?

What happens when dietary fiber that is not fermented reaches the colon?

What is the mechanism of action of phosphate salts like sodium phosphate as laxatives?

What is the effect of fermentation of fiber in the colon?

What is the main effect of nondigestible sugars and alcohols like lactulose, sorbitol, and mannitol?

What do fruits and vegetables primarily contribute to stool transit?

What are the general considerations related to habitual use of laxatives?

What is the distinction between laxation and catharsis or purgation?

How do laxatives act to enhance retention of intraluminal fluid?

What is the main effect of the commonly used laxatives?

When are laxatives employed before surgical, radiological, and endoscopic procedures?

What are the potential complications of laxative use?

What is the main effect of dietary fiber supplements like semisynthetic celluloses (e.g., methylcellulose and calcium polycarbophil)?

What is the main effect of magnesium-containing laxatives?

What is the role of platelet-activating factor in the gut?

What is the effect of fermentation of fiber in the colon?

What is the main effect of dietary fiber that is not fermented?

What is the effect of nondigestible sugars and alcohols like lactulose, sorbitol, and mannitol?

How do osmotically active laxatives, such as magnesium-containing laxatives, work?

What is the main effect of wheat bran as a dietary fiber supplement?

What is the mechanism of action of phosphate salts like sodium phosphate as laxatives?

What is the main effect of psyllium husk as a dietary fiber supplement?

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