digestion and absorption of food
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When I prayed for success, I forgot to ask for sound sleep and good digestion. -Mason Cooley
Happiness: a good bankaccount, a good cook, and agood digestion. #Jean-Jacques Rousseau
Digestion and Absorption of Food
-Dr. Ganesh
Digestion and Absorption of Food
Contents:
Biological Importance
Medical Importance
Digestion and Absorption – General Aspects
Digestion and Absorption of Carbohydrates
Digestion and Absorption of Proteins
Digestion and Absorption of Lipids
Biological Importance
Digestion a chemical process –large molecules in the food arebroken down tosmaller molecules so that they can be absorbed
Biological Importance
large molecules small molecules
small molecules
Food
Digestion
Absorption
vitamins, minerals, monosaccharides and free amino acids
BLOOD
Biological Importance
• Absorption is transport of molecules, either digested products or other small molecules which do not require
digestion, from the intestinal lumen into blood across the intestinal mucosal cells.
Medical Importance
• Lactose intolerancedeficiency of lactaseintake of milk causes diarrhea
• Hartnup’s disease genetic defect in the absorption of neutral amino acids, especially tryptophan.
Medical Importance
• Steatorrhea excess fat is excreted in feces and is seen in diseases of pancreas, biliary obstruction, etc.
• Chronic diarrhea can cause malabsorption as seen in celiac disease, Sprue, Crohn’s disease, etc.
Digestion – General Aspects
major foodstuffs that require digestion
carbohydrates,
proteins
fats and oils (triacylglycerol)
Amino acids
macromolecules
monosaccharides
glycerol and fatty acids
smaller molecules digestion
Digestion takes place in the aqueous medium of
Site of Digestion Digestive Juices
Mouth
Stomach
Small intestinal lumen
Saliva
Gastric juice
Intestinal juice
various digestive juices –
Digestion – General Aspects
Pancreatic juice,
Bile
Digestion – General Aspects
• Digestion involves action of enzymes that are present in different digestive juices. • All digestive enzymes are hydrolases that hydrolyze the anhydride linkages –
Digestion – General Aspects
carbohydrates,
proteins
fats and oils (triacylglycerol)
Glycosidic linkage
Peptide linkage
Ester linkage
anhydride linkages
Digestion – General Aspects
• Bile, synthesized in liver and entering into duodenum,• helps in fat digestion and • neutralizes
acidic stomach contents when it enters the duodenum.
Digestion – General Aspects • Cooking hydration of polysaccharides and denaturation of proteins helps digestion of these molecules. • Mastication helps in breaking down of food particles increases solubility and surface area for enzyme action.• Peristalsis also important in breaking down of food particles and mixing them with enzymes.
Absorption– General Aspects
• small intestine main absorptive organ. About 90% of the ingested foodstuffs absorbed through the small intestine• Considerably more water is absorbed in the large intestine, so that the contents, gradually become more solid in the colon.
Absorption – General Aspects Absorption of substances into mucosal cells involves
the passage across the plasma membrane
simple diffusion carrier-mediated transports
passive
(no energy expenditure)
No carrier protein
facilitated transport
(passive)
(requiring energy expenditure)
active transport
Absorption – General Aspects two pathways for the transport of nutrients
hepatic portal blood lymphatic vessels
water-soluble nutrients lipid-soluble nutrients
blood
thoracic ductliver
absorbed by the intestine
blood
Digestion and Absorption of
Carbohydrates
Contents:
• Introduction • Digestion of Starch• Digestion of Disaccharides • Absorption of Carbohydrates• Clinical Significance
Digestion and Absorption of Carbohydrates
Introduction
major carbohydrates in the diet
Monosaccharides
Disaccharides
Polysaccharides
fructose (present in fruits)
starch
Starch - more than 50% of carbohydrates
sucrose lactose maltose
(present in malt, beer)
Small amounts
dietary fibers
Digestion and Absorption of Carbohydrates - Introduction
• Dietary fibers – cellulose, hemicellulose, pectin, lignins, etc. are indigestible. For ‘Dietary fibers’, see Chapters – ‘Chemistry of Carbohydrates’ and ‘Nutrition’)
Digestion and Absorption of Carbohydrates - Introduction
Human food also contains small amounts of • pentoses, • glucose, • trehalose (disaccharide present in mushroom), and• glycogen (present in liver in animal foods).
Digestion and Absorption of Carbohydrates - Introduction
• All enzymes of carbohydrate digestion cleave glycosidic bonds by hydrolysis.
• Disaccharides and polysaccharides are digested to their respective constituent monosaccharides units and absorbed in the small intestines along with free monosaccharides present in the food
Digestion and Absorption of Carbohydrates - Introduction
• The absorbed monosaccharides
hepatic portal circulation
liver cells
systemic circulation.
Fructose
Sucrose
Starch
Lactose
FOOD
DIGESTION
ABSORPTION (Small Intestine)
Glucose
Galactose
Fructose
Digestion and Absorption of Carbohydrates -Introduction
Digestion of Starch1, 2
• Starch on complete digestion
yields
glucose• Digestion of starch
takes place in • mouth,• small intestinal lumen and • small intestinal brush border
(luminal surface of intestinal mucosal cells).
Digestion of Starch1, 2
• The enzymes and the steps of digestion of glycogen are same as those of amylopectin component of starch as both have similar structure.
• Cooking hydrates the starch granules making it more susceptible to digestion.
Digestion of Starch1, 2
Enzymes required for complete digestion of starch – • amylase (salivary and pancreatic amylase), • maltase and • isomaltase.• Amylase and maltase cleave
-1,4 glycosidic linkages and isomaltase cleaves-1,6 glycosidic linkages of starch. (Amylase hydrolyzes internal -1,4 glycosidic linkages.)
Digestion of Starch• Starch is mainly digested by
pancreatic amylase.
Contribution by salivary amylase is very little since the food remains in the mouth for a very short period of time and the enzyme is inactivated by gastric HCl as it enters stomach.
• Maltase and isomaltase are present on the luminal surface of small intestinal epithelial cells (brush border cells).
Starch (amylose and amylopectin)
Salivary amylase (in mouth)3
Or Pancreatic amylase (in small intestinal lumen
Limit dextrins4 Small unbranched oligosaccharides (e.g., Maltose, Maltotriose, etc)
Isomaltase (brush border cells)Glucose Isomaltose
Maltase Maltase (brush border cells)
Digestion of Starch
Isomaltase
(brush border cells)
• Cl- is an activator of Salivary amylase(ptyalin)
• Limit dextrins derived from amylopectin component by the action of amylase and contain eight glucosyl units with one or two branches with α-1,6-glycosidic bonds.
Digestion of Starch
Digestion of DisaccharidesMajor disaccharides present in the human diet are – • sucrose and • lactoseSmall amounts of • free maltose (present in malt, beer) and • trehalose (disaccharide present in mushroom)
Digestion of Disaccharides
• However, quantitatively the major disaccharide digested in the gut ismaltose
• Most of the maltose in the gut is derived from digestion of starch.
• Isomaltose is another disaccharide derived from starch and is digested by isomaltase. (See ‘Digestion of Starch’).
Digestion of Disaccharides
• Disaccharidases are attached to the surface of the small intestinal brush border cells.
• (For ‘digestion of maltose’, see ‘Digestion of Starch’.)
Digestion of DisaccharidesSite of digestion of disaccharides – small intestinal brush border
maltose
sucrose
lactose
trehalose
disaccharidases
maltase
sucrase (also called invertase)
lactase
trehalase
disaccharides
attached to the surface of the small intestinal brush border cells
2 glucose
Digestion of Disaccharides
maltose
sucrose
lactose
trehalose
maltase
sucrase
lactase
trehalase
glucose + galactose
2 glucose
glucose + fructose
Isomaltose isomaltase
2 glucose
Absorption of Monosaccharides
The major monosaccharides resulting from carbohydrate digestion are –
• D-glucose, • D-galactose and • D-fructose. Absorption is carrier mediated.• Pentoses are absorbed by
simple diffusion.• Monosaccharides are first transported
from the lumen to the small intestinal epithelial cells and then into capillaries of portal venous system.
Absorption of Glucose
from the small intestinal lumen into the intestinal epithelial cells by carrier mediated mechanism involving transporter proteins situated on the luminal surface of intestinal epithelial cells.
• Glucose is absorbed mainly by • 1) Na+-dependent transporter
by secondary active transport and to a less extent by
• 2) Na+-independent transporter by passive transport.
Absorption of Glucosefrom the small intestinal lumen
by carrier mediated mechanism involving transporter proteins 1) Na+-dependent transporter
by secondary active transport and to a less extent by
2) Na+-independent transporter by passive transport
into the intestinal epithelial cells
1. Na+-dependent transporter (SGLT)• This carrier protein carries
glucose or galactose along with sodium ion from the lumen. The driving force for the Na+-dependent transport is derived from the maintenance of low intracellular levels of Na+ by the action of the Na+-K+ATPase (secondary active transport).
2) Na+-independent transporter
Small amounts of glucose, transported by facilitated transportutilizing glucose transporter-5 (GLUT-5).
Transport of glucose from cells to portal venous capillaries:
Glucose is transported from the intestinal epithelial cells into portal venous capillaries by glucose transporter-2 (GLUT-2).
• It is a uniport facilitated transport system, which is sodium independent.
Intestinal Epithelial Cell
Absorption of Glucose
Glucose
Glucose
Glucose
GLUT-5
Intestinal Lumen Na+
Na+
Na+ K+
K+
Na+-dependent transporter (SGLT)
GLUT-2
Portal Capillary Blood
ATP
Na+–K+ ATPase
ADP + Pi
secondary active transportfacilitated transport
Absorption of Glucose
Galactose
GLUT-5
Na+
Na+
Na+ K+
K+
Na+-dependent transporter (SGLT)
GLUT-2
ATP
Na+–K+ ATPase
ADP + Pi
Galactose
Galactose
Fructose
Fructose
Fructose
Absorption of Other Monosaccharides
• Fructose facilitated trasporter GLUT-5, sharing with glucose.• Galactose
Na+-dependant trasporter (SGLT)secodary active transport sharing with glucose
• Any pentose present in food is absorbed by simple diffusion.
Absorption of Other Monosaccharides
• Both fructose and galactose transported from the intestinal epithelial cells into portal venous capillaries by glucose transporter-2 (GLUT-2), sharing with glucose.
Clinical SignificanceLactose Intolerance • This is a common condition
gastrointestinal symptoms like diarrhea, abdominal cramps and flatulenceafter ingestion of milk or milk-based foods
Clinical SignificanceLactose Intolerance • Cause
deficiency of lactase1.Deficiency may be due to
• genetic (primary/inherited) or
• acquired (secondaryto other causes) The reason for acquired lactose intolerance may be damage to intestinal epithelial cells due to colitis, gastroenteritis, alcohol consumption or sudden change into a milk-based diet.
Clinical SignificanceLactose Intolerance • Cause
lactase enzyme
defective at
birth
early onset lactose intolerance
(inherited lactase deficiency).
A significant number of adults
exhibit
late onset lactase deficiency
(primary low lactase activity)
especially
Asian-, Native- and African-Americans.
Osmotic movement of water from the intestines to the lumen
Biochemical basis of Clinical Manifestation
Lactase deficiency
Accumulation of lactose,
(Produced by action of bacteria on lactose in the gut)
organic acids and gases (CO2
and H2)
diarrheaAbdominal cramps
flatulence
Lactose Intolerance
Treatment • avoiding milk• Curd
is an effective treatment, because Lactobacilli in curd contains the enzyme Lactase
Digestion and Absorption of Proteins
Contents:
• Digestion of protein – general aspects• Reactions of protein digestion• Absorption of amino acids• Clinical significance
Digestion of Proteins – General Aspects
Contents:• Introduction• Sites of protein digestion, GIT juices and proteases• Endopetidases and exopetidases• Specificity of proteases• Proteases - zymogen form and activation• Role of HCl in protein digestion
Digestion of Proteins – General Aspects
Introduction
• Digestion of dietary proteins –hydrolysis of peptide bonds catalyzed by a group of enzymes called proteases or peptidasesin the gastrointestinal tract
• • Complete digestion of proteins yields
amino acids.
Digestion of Proteins – General Aspects
Introduction
• Dietary proteins denatured on cooking and therefore, cooked proteins more easily digested1. During the process of denaturation unfolding of protein molecule takes place and thus peptide bonds become more accessible for enzyme action.
Digestion of Proteins – General Aspects
Sites of Protein Digestion, GIT Juices and Proteases
Protein digestion takes place in • stomach and • intestinal lumen.Enzymes of protein digestion are secreted in• gastric juice, • pancreatic juice and • intestinal juice.
Digestion of Proteins – General Aspects
GIT Juices and Proteases
GIT Juices
Gastric juice
Pancreatic Juice
Intestinal Juice
Proteases Present
Pepsin (chief cells of stomach), Rennin2
Trypsin Chymotrypsin Elastase
Carboxypeptidases
Aminopeptidases Dipeptidases
Tripeptidases
Rennin
• Rennin, a protease, active in infants and involved in curdling of milk. Rennin denatures casein of milk to paracasein irreversibly, which then is acted upon by pepsin.
Endopeptidases and Exopeptidases
hydrolyze terminal bond releasing one amino acid at a time.
carboxy terminal
amino terminal
Pepsin
Trypsin
Chymotrypsin
Elastase
Carboxypeptidases
Aminopeptidases
hydrolyze peptide bonds in the interior of the protein chain to
cleave the protein molecule into more than one smaller polypeptides and peptides.
Digestion of Proteins – General Aspects
Specificity of Proteases• Endopeptidases hydrolyze specific peptide bonds in protein molecules. Specificity differs from one protease to another3.
Enzyme Hydrolysis of petide bonds formed by carboxyl groups of
Pepsin Phe, Tyr, Trp, Met
Trypsin Arg, Lys (basic amino acids)
Chymotrypsin Phe, Tyr, Trp, Val, Leu (Aromatic, uncharged amino acids)
Elastase Ala, Gly, Ser (small amino acid residues)
Specificity of Proteases
Digestion of Proteins – General Aspects
Proteases – Zymogen Form and Its Activation
Proteolytic enzymes are secreted as inactive zymogens/proenzymes, which are converted to their active form in the intestinal lumen4.
Digestion of Proteins – General Aspects
Proteases – Zymogen Form and Its Activation
Activation of enzymesinvolves cleavage of small peptides so that active sites are exposed. prevents auto-digestion of the secretory acini.
Digestion of Proteins – General Aspects
Proteases – Zymogen Form and Its Activation
Active Enzyme Inactive Zymogen
Pepsin
Trypsinogen
Pepsinogen
Trypsin
Chymotrypsin Chymotrypsinogen
Elastase Proelastase
Carboxypeptidase Procarboxypeptidase
Digestion of Proteins – General Aspects
Proteases – Zymogen Form and Its Activation
Pepsinogen Pepsin
(Parietal cells of stomach) HCl
Autoactivation
TrypsinTrypsinogen Enterokinase
Autoactivation
(a protease present on the intestinal mucosal membranes)
Digestion of Proteins – General Aspects
Proteases – Zymogen Form and Its Activation
Chymotrypsinogen Chymotrypsin
Proelastase Elastase
Procarboxypeptidase Carboxypeptidase
Trypsin
1) Activation of pepsinogen 2) Denaturation of dietary proteins and 3) Providing optimum pH (pH 2 to 3) for the
action of pepsin. • (HCl also kills microorganisms present in food).
Digestion of Proteins – General Aspects
Role of HCl in Protein Digestion
Reactions of Protein Digestion(In Stomach and Small Intestinal Lumen)
Dietary Proteins
In Stomach PepsinHCl
Gastric Juice
Proteoses + Peptones (polypeptides and smaller polypeptides)
In Small Intestinal Lumen
Trypsin
Chymotrypsin
Elastase
Pancreatic Juice
Small Polypeptides + Peptides
Dietary Proteins
In Stomach PepsinHCl
Gastric Juice
Proteoses + Peptones (polypeptides and smaller polypeptides)
In Small Intestinal Lumen
Trypsin
Chymotrypsin
Elastase
Pancreatic Juice
Small Polypeptides + Peptides
HCl
Proteoses + Peptones (polypeptides and smaller polypeptides)
In Small Intestinal Lumen
Trypsin
Chymotrypsin
Elastase
Pancreatic Juice
Small Polypeptides + Peptides
Carboxypeptidases Pancreatic Juice
Aminopeptidases
Dipeptidases Intestinal Juice
Amino acids
In Small Intestinal Lumen
Absorption of Amino Acidsabsorbed from the intestine into portal blood.• transported by a number of carriers many by secondary active transport –Na+-dependent carrierssimilar to glucose transporter system.
Absorption of Amino AcidsDifferent Na+-dependent carriers are:• Neutral amino acid carrier• Phenylalanine and methionine carrier• Carrier specific for imino acids (proline and
hydroxy proline)There are also Na+-independent carriers specializing in the transport of• Neutral and lipophilic amino acids (e.g. Phe,
Leu)• Cationic amino acids (e.g. Lys)
Clinical Significance
• Allergy to certain food proteins(milk, fish) believed to result from absorption of partially digested proteins.
Clinical Significance
• Defect in non-tropical sprue is located within the mucosal cells of the intestine and permits the polypeptides (resulting from the peptic and tryptic digestion of gluten, the principal protein of wheat) to be absorbed into the circulation and thus elicit the production of antibodies.
Clinical Significance
• Defect in the intestinal amino acid transport systems seen in -- Hartnup’s disease, [defect in intestinal neutral amino acid (Trp) carrier], I-- iminoglycinuria, cystinuria etc.
Clinical Significance
• Acute pancreatitis (acute inflammation of pancreas) caused by autodigestion of pancreas by its proteolytic enzymesa life threatening disorder. Autodigestion is due to unusual conversion of proenzymes into active enzymes by trypsin.
Digestion of Fat (Triacylglycerols)
Contents• Digestion of fat• Digestion of other lipids• Absorption of lipids• Clinical significance
Digestion of Fat (Triacylglycerols)main site Small intestinal lumen
Hydrolysis of ester bonds Fatty acids
Glycerol
Monoacyl glycerols (MAGs)
Lipases
- Pancreatic lipasemain enzyme for digestion of most of the fat
Colipase
a protein secreted by pancreas
cofactor
other lipases
lingual lipase, gastric lipase and intestinal lipase
their contribution is negligible
Bile salts help fat digestion by emulsifying fat
Fat
Role of Bile Salts in Fat Digestion
Bile salts
lower the surface tension
– emulsify fat in the intestine.
– Intestinal peristalsis also helps in this.
present in the bile
Emulsification increases the surface area of
fat droplets
enabling more enzyme (lipase) molecules to
act
and thus
speeding up digestion
Reactions of Digestion of Fat (Triacylglycerol)1
Colipase Pancreatic Juice
Fatty Acid
Triacylglycerol (Fat)
Diacylglycerol (DAG)
Lipase
Colipase
Lipase
Fatty Acid
Monoacylglycerol (MAG)
Glycerol
Colipase
Lipase
Fatty Acid
Reactions of Digestion of Fat (Triacylglycerol)1
Digestion of fat
requires another enzyme also
an isomerase
which isomerzes 2-MAG into 1-MAG,
as lipase cannot hydrolyze 2-MAG.
The major end products of digestion of fat are –
• monoacylglycerols (MAGs), • glycerol and • fatty acids
Reactions of Digestion of Fat (Triacylglycerol)1
Digestion of Other Lipids
Pancreatic secretion also contains
cholesterol esterase
phospholipase A2
cholesterol ester cholesterol
Fatty acid
lysophospholipid phospholipid
Fatty acid
Water-insolubleDigested Products of Lipids
Water-soluble
Absorption of Digested Products of Lipids
MonoacylglycerolsLong-chain fatty acids Cholesterol
MicellesFat-soluble vitamins
Mixed micelles
MonoacylglycerolsLong-chain fatty acids
CholesterolFat-soluble
vitaminsPhospholipids
Apolipoproteins
Triacylglycerol
Chylomicron
ChylomicronLYMPHATIC VESSELS Glycerol(SMCFA)
Short- and Medium-chain fatty acids(SMCFA)
SMALL INTESTINAL LUMEN
PORTAL BLOOD
Glycerol
Intestinal Epithelial Cell
Absorption of Digested Products of Lipids
• Normally over 98% of the dietary lipid is absorbed.
Clinical Significance• Steatorrhea• Chyluria and Chylothorax
When daily excretion of fat in feces more than 6g per day
• may be due to defective digestion or defective absorption of fat.
• - Defective digestion may be due to absence of or deficiency of pancreatic lipase as in chronic diseases of pancreas or surgical removal of pancreas. bile salt
•
Clinical Significance• Steatorrhea• Defective absorption of fat occurs
when bile salts do not enter the intestine as in biliary obstruction (e.g. due to biliary stone)
• - Defective absorption may also be due to malabsorptive diseases e.g. celiac disease, Sprue, Crohn’s disease, etc or surgical removal of large lengths of the intestine.
MCQS on Digestion and Absorption
1. All of the below are true about digestion, EXCEPT,
A. All digestive enzymes are hydrolases. B. Digestion ensures the absorption of
nutrients. C. Sites of digestion in the GIT are mouth,
stomach, and the lumen of small and the large intestines.
D. Vitamins, minerals, monosaccharides and free amino acids do not need digestion.
2. The anhydride linkages that are broken during digestion are:
A.glycosidic, peptide and ester linkages of carbohydrates, proteins and fats, respectively.
B.ester, peptide and glycosidic linkages of carbohydrates, proteins and fats, respectively.
C.glycosidic, peptide and ester linkages of carbohydrates, fats and proteins, respectively.
D.peptide, glycosidic and ester linkages of carbohydrates, proteins and fats, respectively.
3. Factors, other than enzymes that help in digestion are the following, EXCEPT,
A.Cooking B.Exercise C.Mastication D.Peristalsis
4. All the following are true about absorption, EXCEPT,
A.Considerably more water is absorbed in the large intestine than in the small intestines.
B.Absorption of all substances require carrier-mediated transports.
C.Water-soluble nutrients are absorbed through hepatic portal system.
D.Lipid-soluble nutrients are absorbed through the lymphatic vessels.
5. The full set of enzymes required for complete digestion of starch are –
A.amylase, maltase and isomaltase. B.amylase, maltase and sucrase. C.amylase, maltase, isomaltase and sucrase. D.amylase, sucrase and isomaltase.•
6. Contribution by salivary amylase in digestion of starch is very little because:
A.activity of the enzyme is very low.B.the food remains in the mouth for a very short
period of time. C.the food remains in the mouth for a very short
period of time and the enzyme is inactivated by gastric HCl.
D.the enzyme is inactivated by gastric HCl.
7. Which of the following is FALSE about digestion of starch?
A.The enzymes and the steps of digestion of glycogen are same as those of amylopectin component of starch.
B.Cooking hydrates the starch granules making it more susceptible to digestion.
C.Cl- is an activator of salivary amylase. D.Limit dextrins are derived from amylose
component of starch by the action of amylase.
8. Quantitatively the major disaccharide digested in the gut is
A.sucrose B.maltose C.lactose D.isomaltose
9. The major monosaccharides resulting from carbohydrate digestion are
A.glucose, galactose and ribose. B.glucose, mannose and fructose. C.glucose, ribose and fructose. D.glucose, galactose and fructose.
10. Glucose is absorbed mainly by
A.simple diffusion B.Na+-dependent transporter C.Na+-independent transporter D.passive transport•
11. Enzymes of protein digestion are secreted in
A.gastric juice, pancreatic juice and intestinal juice.
B.saliva, gastric juice and pancreatic juice. C.saliva, gastric juice and intestinal juice. D.saliva, gastric juice and intestinal juice.
12. Proteases secreted in the pancreatic juice are
A.pepsin, trypsin, chymotrypsin and carboxypeptidases.
B.trypsin, chymotrypsin, elastase and carboxypeptidases.
C.trypsin, chymotrypsin, elastase and aminopeptidases.
D.trypsin, chymotrypsin, aminopeptidases and carboxypeptidases.
13. HCl has following roles in protein digestion, EXCEPT.
A.kills microorganisms present in food B.activation of pepsinogen C.denaturation of food proteins D.providing optimum pH for the action of
pepsin
14. Intestinal absorption of amino acids involves all of the following, EXCEPT,
A.simple diffusion B.Na+-dependent transporter C.Na+-independent transporter D.passive transport
15. Which of the following is false about action of bile salts?
A.They help both in digestion of fat and absorption of digested products of lipids.
B.They lower the surface tension and emulsify fat in the intestine.
C.They stimulate pancreatic secretion.D.Emulsification increases the surface area
of the fat droplets.
16. Digestion of fat produces:
A.fatty acids, glycerol and diacyl glycerols.
B.fatty acids and glycerol.C.glycerol and monoacyl glycerols.D.fatty acids, glycerol and monoacyl
glycerols.
17. Lipases other than pancreatic lipase present in the human GIT are:
A.salivary lipase, gastric lipase and intestinal lipase
B.lingual lipase, gastric lipase and intestinal
lipase C.lingual lipase, gastric lipase and hepatic lipase D.gastric lipase, biliary lipase and intestinal
lipase
18. Steatorrhea is a condition when daily excretion of fat in feces is more than:
A.6g B.8g C.10g D.12g
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