Oligosaccharidoses: GIT Digestion & Absorption Quiz and Flashcards

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Questions and Answers

Where does the digestion of proteins, fats, and complex carbohydrates primarily occur?

Salivary glands

Liver

Small intestine (correct)

Stomach

Which part of the pancreas is responsible for attacking carbohydrates, proteins, lipids, DNA, and RNA?

Endocrine portion

Islets of Langerhans

Exocrine portion (correct)

Acinar cells

What aids in the digestive process along with enzymes in the small intestine?

Hydrochloric acid from the liver

Saliva from the salivary glands

Mucus secretion

Bile from the pancreas (correct)

Which gland secretes enzymes that attack carbohydrates and fats, in addition to proteins?

Pancreas Signup and view all the answers

In which part of the gastrointestinal system do vitamins, minerals, and water cross the mucosa and get absorbed into the body?

Small intestine Signup and view all the answers

Which organ secretes hydrochloric acid that aids in digestion alongside enzymes?

Stomach Signup and view all the answers

What are the end products of α-amylase digestion of polysaccharides in the small intestine?

Maltose, maltotriose, and α-limit dextrins Signup and view all the answers

Where are the oligosaccharidases responsible for further digestion of starch derivatives located?

In the brush border of small intestinal epithelial cells Signup and view all the answers

Which enzyme is mainly responsible for hydrolysis of 1:6α linkages?

Isomaltase Signup and view all the answers

How is sucrase formed in the small intestine?

By pancreatic proteases hydrolyzing a glycoprotein chain into sucrase Signup and view all the answers

What is the result of lactase enzyme activity?

Glucose and galactose Signup and view all the answers

What symptoms may arise due to a deficiency in brush border oligosaccharidases?

Diarrhea, bloating, and flatulence Signup and view all the answers

What are symptoms experienced by individuals with lactose intolerance after ingesting dairy products?

Bloating, pain, gas, and diarrhea Signup and view all the answers

Why is yogurt better tolerated than milk in lactose intolerant individuals?

Yogurt contains its own bacterial lactase Signup and view all the answers

How are hexoses absorbed across the wall of the small intestine?

By active transport involving Na+ Signup and view all the answers

What is the role of Na+ in the absorption of glucose and galactose in the intestinal lumen?

Facilitates sugar influx into epithelial cells Signup and view all the answers

Why is avoiding dairy products challenging for individuals with lactose intolerance?

Dairy products are a major part of many diets Signup and view all the answers

What is the simplest treatment for lactose intolerance?

Avoiding all carbohydrates Signup and view all the answers

What is the function of micelles in the context of lipid absorption in the gastrointestinal system?

Serving as carriers to transport lipids to the enterocytes Signup and view all the answers

How are lipids maintained in contact with the brush border of mucosal cells during absorption?

Through micelles that collect lipids Signup and view all the answers

What is the current understanding regarding how lipids enter enterocytes during fat absorption?

By carriers involvement Signup and view all the answers

Which components are found in the hydrophobic center of micelles involved in lipid absorption?

Cholesterol and amphipathic phospholipids Signup and view all the answers

What role do micelles play in relation to lipid solubilization?

Facilitating lipid solubilization and transport Signup and view all the answers

Why are lipids rapidly esterified inside the enterocytes during fat absorption?

To maintain a favorable concentration gradient from lumen to cells Signup and view all the answers

Where does the acylation of glycerophosphate and the formation of lipoproteins occur?

Rough endoplasmic reticulum Signup and view all the answers

In which part of the small intestine is absorption of long-chain fatty acids greatest?

Upper parts Signup and view all the answers

How much of ingested fat is absorbed on a moderate fat intake?

95% Signup and view all the answers

Why are infants more susceptible to the ill effects of disease processes that reduce fat absorption?

Their fat absorption processes are not fully mature Signup and view all the answers

How is the amount of iron lost from the body regulated in adults?

Changes in the rate of absorption from the intestine Signup and view all the answers

How much iron do men lose daily from their body?

0.6 mg Signup and view all the answers

What is the mechanism by which protein antibodies in maternal colostrum cross the mammary epithelium and enter the circulation of the infant?

Endocytosis Signup and view all the answers

What is the primary method of absorption for intact proteins in adults?

Endocytosis Signup and view all the answers

Which of the following foods is NOT mentioned as being allergenic in the text?

Seeds Signup and view all the answers

What percentage of children is reported to have food allergies according to the text?

8% Signup and view all the answers

In individuals with food allergies, what may cause allergic symptoms upon subsequent consumption of the same protein?

Antigen–antibody reaction Signup and view all the answers

What role do foreign proteins that enter the circulation play in relation to allergic responses?

They provoke the formation of antibodies Signup and view all the answers

Which enzyme is responsible for hydrolyzing the 1- and 3-bonds of triglycerides in fat digestion?

Pancreatic lipase Signup and view all the answers

What is the main function of colipase in fat digestion?

Facilitating the opening of the active site on pancreatic lipase Signup and view all the answers

Where is lingual lipase secreted in the digestive system?

Stomach Signup and view all the answers

What do lingual lipase and stomach lipase generate that signals to the gastrointestinal tract?

Free fatty acids Signup and view all the answers

Which bonds of triglycerides are hydrolyzed at a low rate by pancreatic lipase?

2-bonds Signup and view all the answers

What facilitates pancreatic lipase activity when acting on emulsified fats?

-COOHterminal domain Signup and view all the answers

What causes anemia according to the text?

Iron overload Signup and view all the answers

In hemochromatosis, what does the pigmentation of the skin indicate?

Hemosiderin accumulation Signup and view all the answers

What is the function of the mutated HFE gene in hemochromatosis?

Inhibits iron absorption Signup and view all the answers

Which factor plays a role in regulating intestinal absorption of iron?

State of erythropoiesis in the bone marrow Signup and view all the answers

What is a consequence of large amounts of hemosiderin accumulation?

Hepatic carcinoma Signup and view all the answers

Where is the mutated HFE gene located in those affected by hemochromatosis?

Short arm of chromosome 6 Signup and view all the answers

Where do amino acids released from peptides get transported out of the enterocytes?

Along basolateral borders Signup and view all the answers

What percentage of the digested protein comes from proteins in digestive juices?

25% Signup and view all the answers

Where does the majority of the free amino acids get assimilated, leading to little absorption in the ileum?

Jejunum Signup and view all the answers

What is the fate of almost all the protein found in stools according to the text?

Comes from bacterial action in the colon Signup and view all the answers

What do studies suggest about the peptidase activities of brush border and mucosal cell cytoplasm when part of the ileum is resected?

Increased Signup and view all the answers

What regulation do the enzyme activities related to peptidases in brush border and mucosal cells appear to be subject to?

Homeostatic regulation Signup and view all the answers

What is the role of micelles in the absorption of lipids in the gastrointestinal system?

Facilitating the diffusion of lipids to the brush border of mucosal cells Signup and view all the answers

How are lipids maintained in solution during the absorption process in the gastrointestinal system?

By forming micelles with hydrophobic centers Signup and view all the answers

What is the main function of carriers in the process of lipid absorption in enterocytes?

Aiding in the transport of lipids into enterocytes Signup and view all the answers

How do fatty acids and monoglycerides align themselves within the micelles during lipid absorption?

Hydrophilic heads outside and hydrophobic tails inside Signup and view all the answers

What happens to lipids once they reach the brush border of mucosal cells in the gastrointestinal system?

They are absorbed by the cells Signup and view all the answers

Why are carriers suggested to be involved in lipid absorption into enterocytes?

To actively transport lipids across the cell membrane Signup and view all the answers

What is the optimal pH for salivary α-amylase?

6.7 Signup and view all the answers

Which molecule constitutes around 75% of dietary starch and is branched?

Amylopectin Signup and view all the answers

Which disaccharide is also known as milk sugar?

Lactose Signup and view all the answers

Which type of carbohydrates are digested to any significant degree in the human gastrointestinal tract by human enzymes?

Polysaccharides Signup and view all the answers

Where does digestion of starch by salivary α-amylase begin?

Mouth Signup and view all the answers

Which monosaccharide is ingested along with lactose and sucrose?

Galactose Signup and view all the answers

What is the primary reason that makes yogurt better tolerated than milk in lactose intolerant individuals?

Yogurt contains its own bacterial lactase. Signup and view all the answers

How do hexoses like glucose and galactose get transported into the epithelial cells of the small intestine?

Facilitated by Na+ ions Signup and view all the answers

Why is the simplest treatment for lactose intolerance mentioned as avoiding dairy products?

Lactose in dairy products is not sufficiently digested. Signup and view all the answers

What is the role of commercial lactase preparations in treating symptoms of lactose intolerance?

They aid in the breakdown of lactose into absorbable sugars. Signup and view all the answers

Why are hexoses absorbed rapidly across the wall of the small intestine?

Because hexoses are actively transported Signup and view all the answers

What causes symptoms like bloating, pain, and diarrhea in individuals with lactose intolerance?

Unabsorbed osmoles from lactose digestion Signup and view all the answers

What is the primary location for rapid absorption of amino acids in the gastrointestinal system?

Jejunum Signup and view all the answers

Where does almost all the protein in stools come from according to the text?

Bacterial action in the colon Signup and view all the answers

What percentage of digested protein comes from desquamated mucosal cells?

25% Signup and view all the answers

Which location experiences little absorption due to assimilation of free amino acids?

Ileum Signup and view all the answers

What is the fate of only 2–5% of the protein in the small intestine?

Bacterial digestion in the colon Signup and view all the answers

How are peptidase activities of brush border and mucosal cell cytoplasm altered during starvation?

Increased Signup and view all the answers

What is the main role of hephaestin (Hp) in iron transport?

Facilitating basolateral transport Signup and view all the answers

What is the normal plasma iron level in women according to the text?

110 μg/dL Signup and view all the answers

Where is most of the iron stored in the body?

Hemoglobin Signup and view all the answers

What is the composition of apoferritin?

24 subunits Signup and view all the answers

What are deposits containing as much as 50% iron called?

Hemosiderin Signup and view all the answers

What removes Fe2+ from porphyrin and adds it to the intracellular Fe2+ pool?

HO-2 Signup and view all the answers

What can lead to hemosiderosis according to the text?

Iron overload Signup and view all the answers

What genetic disorder is characterized by pigmentation of the skin, pancreatic damage with diabetes, and cirrhosis of the liver?

Hemochromatosis Signup and view all the answers

Where is the mutated HFE gene that commonly leads to hereditary hemochromatosis located?

Short arm of chromosome 6 Signup and view all the answers

What is one of the characteristics associated with hemochromatosis?

Gonadal atrophy Signup and view all the answers

How do individuals who are homogenous for HFE mutations absorb excess iron?

Due to inhibited expression of duodenal transporters Signup and view all the answers

Which area is closely linked to the locus where the mutated HFE gene responsible for hemochromatosis is located?

HLA-A locus Signup and view all the answers

What is the primary function of the gastrointestinal tract?

To absorb nutrients and water into the body Signup and view all the answers

Where do glandular structures deliver secretions in the gastrointestinal tract?

In the stomach and mouth Signup and view all the answers

What organs drain secretions into the gastrointestinal tract?

Pancreas, gallbladder, and salivary glands Signup and view all the answers

Which part of the gastrointestinal tract is encountered first by a meal or its residues?

Mouth Signup and view all the answers

Where is the acylation of glycerophosphate and the formation of lipoproteins important in the digestive process?

Pancreas Signup and view all the answers

What is an essential function of secretions from the pancreas and biliary system in digestion?

To aid in lipid digestion Signup and view all the answers

Which pancreatic enzyme is released as an inactive precursor and activated by trypsin?

Trypsinogen Signup and view all the answers

Why does the pancreas secrete a trypsin inhibitor?

To prevent self-digestion of the pancreas Signup and view all the answers

What is the role of somatostatin in the gastrointestinal system?

Inhibits the secretion of GIP and secretin Signup and view all the answers

What is the primary cause of gastric and duodenal ulceration related to in humans?

Breakdown of the mucosa barrier Signup and view all the answers

Where is ghrelin primarily secreted from?

Stomach Signup and view all the answers

What is the primary function of bile in the gastrointestinal system?

To aid in the digestion and absorption of fats Signup and view all the answers

What disrupts the barrier preventing irritation and autodigestion of the mucosa according to the text?

Aspirin and NSAIDs Signup and view all the answers

What stimulates the secretion of somatostatin?

Acid in the gastrointestinal lumen Signup and view all the answers

What color is bile primarily responsible for?

Golden yellow Signup and view all the answers

What is a common cause of ulceration besides infection and overproduction of acid mentioned in the text?

Zollinger–Ellison syndrome Signup and view all the answers

What controls the secretion of pancreatic juice primarily?

Hormonal regulation Signup and view all the answers

Which cells secrete motilin in the gastrointestinal system?

Enterochromaffin cells Signup and view all the answers

How does somatostatin impact the absorption of nutrients in the gastrointestinal system?

Inhibits glucose absorption Signup and view all the answers

Which substance is released into the bloodstream along with protons to neutralize gastric acidity?

Bicarbonate ions Signup and view all the answers

How is bile similar to pancreatic juice?

Both contain electrolytes Signup and view all the answers

What is the function of somatostatin in relation to pancreatic exocrine secretion?

Inhibits pancreatic exocrine secretion Signup and view all the answers

What is the effect of NSAIDs on gastric mucosa that can contribute to ulcer development?

Inhibition of prostaglandin production Signup and view all the answers

Where are most gastrinomas found in patients with Zollinger–Ellison syndrome?

Pancreas Signup and view all the answers

What is the primary function of the myenteric plexus in the gastrointestinal system?

Motor control of smooth muscle layers Signup and view all the answers

Which neurotransmitter is NOT mentioned as part of the gastrointestinal system?

Insulin Signup and view all the answers

What is the main purpose of digestive secretions in the gastrointestinal system?

To digest meals into absorbable components Signup and view all the answers

Which component is NOT part of the sequential action on meal components in the gastrointestinal system?

Cerebrospinal fluid Signup and view all the answers

Which area of the body is functionally continuous with the outside environment according to the text?

Gastrointestinal system Signup and view all the answers

Which substance's presence is NOT associated with the regulation of intestinal functions in the gastrointestinal system?

Hyaluronic acid Signup and view all the answers

Study Notes

Digestion of Macromolecules

Proteins, fats, and complex carbohydrates are primarily digested in the small intestine.
Pancreatic juice contains enzymes that break down carbohydrates, proteins, lipids, DNA, and RNA.

Carbohydrate Digestion

Amylase breaks down polysaccharides into oligosaccharides in the small intestine.
Oligosaccharidases, such as sucrase, are responsible for further digestion of starch derivatives in the brush border of enterocytes.
Sucrase is formed in the small intestine and breaks down sucrose into glucose and fructose.
Lactase breaks down lactose into glucose and galactose.
α-Amylase is primarily responsible for breaking down starch into oligosaccharides in the small intestine.

Lipid Digestion

Lipase breaks down triglycerides into fatty acids and monoglycerides in the small intestine.
Bile salts emulsify lipids, increasing the surface area for enzymatic digestion.
Micelles are formed from bile salts and lipids, facilitating lipid absorption.
Fatty acids and monoglycerides are transported across the enterocyte membrane via carriers.
Lipoproteins are formed in the enterocytes and transported to the lymphatic system.

Fat Absorption

Micelles play a crucial role in lipid solubilization and absorption in the small intestine.
Lipids are maintained in contact with the brush border of mucosal cells during absorption.
Acylation of glycerophosphate and formation of lipoproteins occur in the enterocytes.

Iron Absorption

Iron is absorbed in the duodenum and proximal jejunum.
The amount of iron lost from the body is regulated in adults.
Men lose approximately 1 mg of iron daily from their bodies.
Hemochromatosis is a genetic disorder characterized by increased iron absorption and storage.

Protein Digestion

Proteins are primarily digested in the small intestine by pancreatic enzymes.
Amino acids are absorbed in the small intestine and transported to the liver.
The primary location for rapid absorption of amino acids is the proximal small intestine.
Almost all protein in stools comes from desquamated mucosal cells.

Gastrointestinal System

The primary function of the gastrointestinal tract is to break down and absorb nutrients.
Secretions from the pancreas and biliary system aid in digestion.
Glandular structures deliver secretions into the gastrointestinal tract.
The small intestine is the primary site for nutrient absorption.

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Learn about lactose intolerance and the symptoms individuals experience when ingesting dairy products. Explore therapeutic highlights and treatment options for managing lactose intolerance symptoms.

Chapter 26 | GIT Digestion &amp; Absorption

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Questions and Answers

Where does the digestion of proteins, fats, and complex carbohydrates primarily occur?

Which part of the pancreas is responsible for attacking carbohydrates, proteins, lipids, DNA, and RNA?

What aids in the digestive process along with enzymes in the small intestine?

Which gland secretes enzymes that attack carbohydrates and fats, in addition to proteins?

In which part of the gastrointestinal system do vitamins, minerals, and water cross the mucosa and get absorbed into the body?

Which organ secretes hydrochloric acid that aids in digestion alongside enzymes?

What are the end products of α-amylase digestion of polysaccharides in the small intestine?

Where are the oligosaccharidases responsible for further digestion of starch derivatives located?

Which enzyme is mainly responsible for hydrolysis of 1:6α linkages?

How is sucrase formed in the small intestine?

What is the result of lactase enzyme activity?

What symptoms may arise due to a deficiency in brush border oligosaccharidases?

What are symptoms experienced by individuals with lactose intolerance after ingesting dairy products?

Why is yogurt better tolerated than milk in lactose intolerant individuals?

How are hexoses absorbed across the wall of the small intestine?

What is the role of Na+ in the absorption of glucose and galactose in the intestinal lumen?

Why is avoiding dairy products challenging for individuals with lactose intolerance?

What is the simplest treatment for lactose intolerance?

What is the function of micelles in the context of lipid absorption in the gastrointestinal system?

How are lipids maintained in contact with the brush border of mucosal cells during absorption?

What is the current understanding regarding how lipids enter enterocytes during fat absorption?

Which components are found in the hydrophobic center of micelles involved in lipid absorption?

What role do micelles play in relation to lipid solubilization?

Why are lipids rapidly esterified inside the enterocytes during fat absorption?

Where does the acylation of glycerophosphate and the formation of lipoproteins occur?

In which part of the small intestine is absorption of long-chain fatty acids greatest?

How much of ingested fat is absorbed on a moderate fat intake?

Why are infants more susceptible to the ill effects of disease processes that reduce fat absorption?

How is the amount of iron lost from the body regulated in adults?

How much iron do men lose daily from their body?

What is the mechanism by which protein antibodies in maternal colostrum cross the mammary epithelium and enter the circulation of the infant?

What is the primary method of absorption for intact proteins in adults?

Which of the following foods is NOT mentioned as being allergenic in the text?

What percentage of children is reported to have food allergies according to the text?

In individuals with food allergies, what may cause allergic symptoms upon subsequent consumption of the same protein?

What role do foreign proteins that enter the circulation play in relation to allergic responses?

Which enzyme is responsible for hydrolyzing the 1- and 3-bonds of triglycerides in fat digestion?

What is the main function of colipase in fat digestion?

Where is lingual lipase secreted in the digestive system?

What do lingual lipase and stomach lipase generate that signals to the gastrointestinal tract?

Which bonds of triglycerides are hydrolyzed at a low rate by pancreatic lipase?

What facilitates pancreatic lipase activity when acting on emulsified fats?

What causes anemia according to the text?

In hemochromatosis, what does the pigmentation of the skin indicate?

What is the function of the mutated HFE gene in hemochromatosis?

Which factor plays a role in regulating intestinal absorption of iron?

What is a consequence of large amounts of hemosiderin accumulation?

Where is the mutated HFE gene located in those affected by hemochromatosis?

Where do amino acids released from peptides get transported out of the enterocytes?

What percentage of the digested protein comes from proteins in digestive juices?

Where does the majority of the free amino acids get assimilated, leading to little absorption in the ileum?

What is the fate of almost all the protein found in stools according to the text?

What do studies suggest about the peptidase activities of brush border and mucosal cell cytoplasm when part of the ileum is resected?

What regulation do the enzyme activities related to peptidases in brush border and mucosal cells appear to be subject to?

What is the role of micelles in the absorption of lipids in the gastrointestinal system?

How are lipids maintained in solution during the absorption process in the gastrointestinal system?

What is the main function of carriers in the process of lipid absorption in enterocytes?

How do fatty acids and monoglycerides align themselves within the micelles during lipid absorption?

What happens to lipids once they reach the brush border of mucosal cells in the gastrointestinal system?

Why are carriers suggested to be involved in lipid absorption into enterocytes?

What is the optimal pH for salivary α-amylase?

Which molecule constitutes around 75% of dietary starch and is branched?

Which disaccharide is also known as milk sugar?

Which type of carbohydrates are digested to any significant degree in the human gastrointestinal tract by human enzymes?

Where does digestion of starch by salivary α-amylase begin?

Which monosaccharide is ingested along with lactose and sucrose?

What is the primary reason that makes yogurt better tolerated than milk in lactose intolerant individuals?

How do hexoses like glucose and galactose get transported into the epithelial cells of the small intestine?

Why is the simplest treatment for lactose intolerance mentioned as avoiding dairy products?

What is the role of commercial lactase preparations in treating symptoms of lactose intolerance?

Why are hexoses absorbed rapidly across the wall of the small intestine?

What causes symptoms like bloating, pain, and diarrhea in individuals with lactose intolerance?

What is the primary location for rapid absorption of amino acids in the gastrointestinal system?

Where does almost all the protein in stools come from according to the text?

What percentage of digested protein comes from desquamated mucosal cells?

Which location experiences little absorption due to assimilation of free amino acids?

What is the fate of only 2–5% of the protein in the small intestine?

Chapter 26 | GIT Digestion & Absorption