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Obesity is a condition that affects over 30% of adults in the United States and is associated with comorbidities such as type 2 diabetes mellitus, heart disease, and cancer. For individuals with clinically severe obesity, defined as having a body mass index above 40 kg/m², lifestyle interventions may produce insufficient weight reduction. Weight loss surgery, such as Roux-en-Y gastric bypass (RYGB) , has proved to be the most effective clinical intervention for facilitating massive and immediate weight loss in clinically obese patients.In RYGB, the stomach is first divided into a small gastric pouch and a distal gastric remnant, which remains attached to the duodenum. Next, the jejunum is transected and its lower section is connected to the newly created gastric pouch to form the alimentary limb. This connection is typically created with surgical staples. The formation of the alimentary limb allows ingested food to bypass the region composed of the distal gastric remnant, the duodenum, and the upper jejunum; collectively termed the biliopancreatic limb. Finally, the lumen of the upper jejunum is reconnected to the lumen of the lower jejunum to allow enzymes and compounds to flow freely from the biliopancreatic limb into the alimentary limb.
Figure 1 RYGB surgically divides the digestive tract into the alimentary limb and the biliopancreatic limb, which then merge into the common limb.RYGB facilitates weight loss by reducing the functional volume of the stomach and altering intestinal anatomy to induce nutrient malabsorption. However, the procedure is associated with several complications, such as steatorrhea, or fatty stools, due to disruption of lipid digestion. Animal studies also suggest that RYGB promotes the growth of weight loss-inducing gut bacteria. Researchers have found that transplanting gut microbiota of obese postoperative RYGB mice into nonoperated, obese mice lacking gut flora may reproduce the therapeutic effects of RYGB in transplant-recipient mice.
Adapted from Bächler T, Le roux CW, Bueter M. How do patients' clinical phenotype and the physiological mechanisms of the operations impact the choice of bariatric procedure?. Clin Exp Gastroenterol. 2016;9:181-9.
-Which organ synthesizes a compound that facilitates the mechanical digestion of lipids?

Question

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Obesity is a condition that affects over 30% of adults in the United States and is associated with comorbidities such as type 2 diabetes mellitus, heart disease, and cancer. For individuals with clinically severe obesity, defined as having a body mass index above 40 kg/m², lifestyle interventions may produce insufficient weight reduction. Weight loss surgery, such as Roux-en-Y gastric bypass (RYGB) , has proved to be the most effective clinical intervention for facilitating massive and immediate weight loss in clinically obese patients.In RYGB, the stomach is first divided into a small gastric pouch and a distal gastric remnant, which remains attached to the duodenum. Next, the jejunum is transected and its lower section is connected to the newly created gastric pouch to form the alimentary limb. This connection is typically created with surgical staples. The formation of the alimentary limb allows ingested food to bypass the region composed of the distal gastric remnant, the duodenum, and the upper jejunum; collectively termed the biliopancreatic limb. Finally, the lumen of the upper jejunum is reconnected to the lumen of the lower jejunum to allow enzymes and compounds to flow freely from the biliopancreatic limb into the alimentary limb.

Figure 1 RYGB surgically divides the digestive tract into the alimentary limb and the biliopancreatic limb, which then merge into the common limb.RYGB facilitates weight loss by reducing the functional volume of the stomach and altering intestinal anatomy to induce nutrient malabsorption. However, the procedure is associated with several complications, such as steatorrhea, or fatty stools, due to disruption of lipid digestion. Animal studies also suggest that RYGB promotes the growth of weight loss-inducing gut bacteria. Researchers have found that transplanting gut microbiota of obese postoperative RYGB mice into nonoperated, obese mice lacking gut flora may reproduce the therapeutic effects of RYGB in transplant-recipient mice.
Adapted from Bächler T, Le roux CW, Bueter M. How do patients' clinical phenotype and the physiological mechanisms of the operations impact the choice of bariatric procedure?. Clin Exp Gastroenterol. 2016;9:181-9.
-Which organ synthesizes a compound that facilitates the mechanical digestion of lipids?

Quizplus · Accepted Answer

11ecba2d_0f9d_d7e8_a3bf_97bdd25586ad_MD0008_00 The liver synthesizes bile, a nonenzymatic solution stored in the gallbladder and released into the small intestine to aid in the mechanical digestion of lipids. Bile is composed of bile salts, bile pigments (eg, bilirubin), and cholesterol. Bile salts act as detergents to solubilize fats during digestion and possess both a hydrophobic region that associates with the surface of lipids and a hydrophilic region that associates with water. Consequently, bile salts break down large lipid globules into smaller droplets (micelles) in a process known as emulsification. Emulsification is an example of mechanical digestion, which physically breaks down food particles into smaller pieces. Additional examples of mechanical digestion include chewing in the mouth and churning in the stomach due to peristaltic waves. (Choice A) Chemical digestion is carried out by acids and enzymes and involves the cleavage of chemical bonds within macronutrients to form simpler compounds that can be absorbed. Emulsified lipids have increased surface area on which pancreatic lipase can exert its enzymatic effect (ie, chemical digestion of lipids). As a result, lipase secreted from the pancreas facilitates the chemical digestion (hydrolysis) of triglycerides within micelles into free fatty acids and monoglycerides. (Choice B) The salivary glands are exocrine glands in the mouth that secrete saliva, a lubricating fluid that contains the enzymes lipase and amylase. Lingual lipase facilitates the chemical, not mechanical, digestion of lipids. In contrast, salivary amylase hydrolyzes (chemically digests) the polysaccharide starch into the disaccharide maltose. (Choice C) The gallbladder synthesizes no digestive compounds and serves only as a reservoir (storage site) for bile produced by the liver. Educational objective: Bile is synthesized in the liver, stored in the gallbladder, and released into the duodenum to aid lipid digestion. Bile salts, a key component of bile, mechanically digest lipid globules by physically breaking them down into smaller droplets in a process known as emulsification. Subsequently, pancreatic lipase chemically digests emulsified lipids.

Passage Obesity Is a Condition That Affects Over 30% of Adults