Digestion and Absorption in the GI Tract Flashcards
How does lactase deficiency lead to increased osmotic pressure in the lumen?
If lactase is deficient, then lactose is unable to be broken down and absorbed. Lactose itself is nonabsorbable and holds water in the lumen which cause the increase in osmotic pressure
What does lactose that rermains in the lumen get fermented into? (2)
A. Ethane and H2O
B. Methane and H2O
C. Methane and H+
D. None of the above
Methane and H+
What are the 3 primary sugars in the human diet?
Sucrose. Lactose. Starch
T/F: Amylose, Glycogen, EtOH/alcohol, lactic acid, pyruvic acid, pectins, and dextrins are all secondary sugars found in the human diet
True
Where does carbohydrate digestion occur?
A. Mouth and stomach
B. Stomach and Small Intestine
C. Mouth and Small Intestine
D. Mouth and Large Intestine
Mouth and Small Intestine
Pancreatic amylase and Salivary amylase found in the small intestine and mouth respectively break down starch into what?
Maltose and 3-9 glucose polymers
Brush border enterocytes finish the breakdown of disacharides to monosacharides because only monosacharides are absorbed in the small intestine. All of the following disacharides get broken down into glucose and glucose, EXCEPT for which of the following? Select all that apply and express what monosacharides they break down into.
A. alpha-dextrin
B. maltose
C. maltotriose
D. trhalose
E. lactose
F. sucrose
Lactose: glucose and galactose
Sucrose: glucose and fructose
Which of the following monosacharides utilize secondary active transport and facilitated diffusion to traverse through epithelial cells of the small intestine?
A. Galactose and Glucose
B. Galactose and Fructose
C. Fructose and Glucose
D. Glucose only
Galactose and Glucose
NOTE: Fructose only moves through via facilitated fusion
In the absorption of carbohydrates, Na/K ATPase in the basolateral membrane is necessary for creating a concentration gradient that allows glacatose, glucose, and fructose to be transported though.
What transport mechanisms are utilized by the big three to get into the cell from the lumen?
What transport mechanism is utilized by the big three to get out of the cell and into the blood?
Galactose and Glucose: SGLT1
Fructose: GLUT5
Glucose, Galactose, Fructose: GLUT2
T/F: Dxylose is a pentose monosacharide that is used to test the absorbative capacity of the proximal small intestine due to its ability to utilize SGLT1 or be absorbed via passive diffusion
True
The following diseases result due to either a deficiency of pancreatic enzymes, or a defect in the transport of intestinal epithelial cells. Which of the diseases is specifically due to deficiency in pancreatic enzyme proteases like trypsinogen?
A. Hartnup disease
B. Cystinuria
C. Chronic Pancreatitis
D. Cystic Fibrosis
E. Congenital Trypsin Absence
Chronic Pancreatitis
The following diseases result due to either a deficiency of pancreatic enzymes, or a defect in the transport of intestinal epithelial cells. Which of the diseases is due to loss of all pancreatic enzymes resultin in the absence of trypsin?
A. Hartnup disease
B. Cystinuria
C. Chronic Pancreatitis
D. Cystic Fibrosis
E. Congenital Trypsin Absence
Congenital Trypsin Absence
The following diseases result due to either a deficiency of pancreatic enzymes, or a defect in the transport of intestinal epithelial cells. What diesase is caused by a defect in SLG3A1 or absence of dibasic transporter SLC7A9 meaning we’d probably see large amounts of cysteine, lysine, arginine, ornithine in the feces?
A. Hartnup disease
B. Cystinuria
C. Chronic Pancreatitis
D. Cystic Fibrosis
E. Congenital Trypsin Absence
Cystinuria
- defect in SLG3A1 or SLC7A9
The following diseases result due to either a deficiency of pancreatic enzymes, or a defect in the transport of intestinal epithelial cells. What diesase do we see a failure to absorb neutral AAs like tryptophan or its by-products like serotonin? (symptoms resemble niacin deficiency)
A. Hartnup disease
B. Cystinuria
C. Chronic Pancreatitis
D. Cystic Fibrosis
E. Congenital Trypsin Absence
Hartnup disease
- diarrhea, mood changes, neurological problems, red-scaly rash, photosensitivity, short
The following diseases result due to either a deficiency of pancreatic enzymes, or a defect in the transport of intestinal epithelial cells. What disease often results from mutation of the CFTR Cl- channel on pancreatic duct cell’s apical border leading to loss of HCO3 secretion for neutralizing pH in duodenum?
A. Hartnup disease
B. Cystinuria
C. Chronic Pancreatitis
D. Cystic Fibrosis
E. Congenital Trypsin Absence
Cystic Fibrosis
or Acute/Chronic Pancreatitis
Which of the following is not essential for protein digestion?
A. Stomach; pepsin
B. Pancreas; trypsin, chymotrypsin, carboxypeptidase, elastase
C. Small intestine: eminopeptidases and dipeptidases
D. All of the above are essential
Stomach; pepsin
Pancreatic and brush border enzyme proteases ALONE can adequately digest ingested proteins
T/F: Only amino acids, di- or tri- peptides are absorbable
True
Which of the following pancreatic enzymes work specifically on small peptides?
A. Trypsin and chymotrypsin
B. Carboxypeptidases and chymotrypsin
C. Trypsin and carboxypeptidases
D. All of the above
Trypsin and chymotrypsin
NOTE: Carboxypeptidases cleave AAs into carboxyl ends
Amino acids are absorbed from the lumen into the cell by apical Na-AA cotransporters that are energized by the actions of the Na/K ATPase located at the basolateral membrane. There are 4 seperate transporters for each AA type. What are those 4 types?
Neutral
Acidic
Basic
Imino
NOTE: once in the cell, they are transported across the basolateral membrane and into the blood via Facilitated diffusion based on there make up (as state above)
What type of transporter found in the apical membrane moves dipeptides and tripeptides into the cell?
A. Na-dependent cotransporter
B. Na-independent cotransporter
C. H+-dependent cotransporter
D. H+- independent cotransporter
H+-dependent cotransporter
NOTE: In the cell cytosolic peptidases break them down into AAs and they exit via facilitated diffusion just like the other AAs
Which of the following is true of Celiac Sprue/Disease? Select all that apply
A. Leads to malabsorption related to deficiencies in folate(B9), iron, calcium, vitamin A, vitamin B12, and vitamin D
B. Damage done to jejunum and ileum
C. Damage done to duodenum
D. Malabsorption of folate(B9) and vitamin B12
Leads to malabsorption related to deficiencies in folate(B9), iron, calcium, vitamin A, vitamin B12, and vitamin D
Damage done to duodenum?
Which of the following is true of Tropical Sprue?
Select all that apply
A. Leads to malabsorption related to deficiencies in folate(B9), iron, calcium, vitamin A, vitamin B12, and vitamin D
B. Damage done to jejunum and ileum
C. Damage done to duodenum
D. Malabsorption of folate(B9) and vitamin B12
Damage done to jejunum and ileum
Malabsorption of folate(B9) and vitamin B12
NOTE: Folate (jejunum) B12 (ileum)
Administration of which of the following substances would increase the amount of time lingual lipase and gastric lipase get to act on TAGs in the stomach?
A. Secretin
B. Ghrelin
C. CCK
D. Gastrin
CCK
Most digestion of fat occurs in the small intesitne with the work of the following pancreatic enzymes. What enzyme is the only one that secreted as a proenzyme and needs to be activated by trypsin first?
A. Pancreatic lipase
B. Cholesterol ester hydrolase
C. Phospholipase A2
D. None of the above
Phospholipase A2
Most digestion of fat occurs in the small intesitne with the work of the following pancreatic enzymes. What enzyme is secreted as an active enzyme, but bile salts keep it inactivated until colipase displaces the bile salt?
A. Pancreatic lipase
B. Cholesterol ester hydrolase
C. Phospholipase A2
D. None of the above
Pancreatic lipase
- increase in bile salts will probs keep this thing inactive not good
Most digestion of fat occurs in the small intesitne with the work of the following pancreatic enzymes. What enzyme catalyzes free cholesterol production and hydrolyzes triglycerids to glycerol?
A. Pancreatic lipase
B. Cholesterol ester hydrolase
C. Phospholipase A2
D. None of the above
Cholesterol ester hydrolase
Final products that can be absorbed after fat digestion include what substance?
A. Lysolecithin
B. Glycerol
C. Monoglycerides
D. Cholesterol
E. Fatty acids
F. All of the above
All of the above
Where do bile salts get absorbed?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
Ileum
Most lipids get absorbed midway through what structure?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
Jejunum
During fat absorption, once lipids are re-esterfied with FFA’s in the SER, they get packaged into chylomicrons with ApoB. These chylomicrons are released via exocytosis into lymphatics at what structure?
A. Cistern chyli
B. Thoracic duct
C. Inferior Vena Cava
D. Axillary Lymph node
Thoracic duct
What is the name of the condition where patients cannot absorb lipids becausethe lack of ability to form ApoB means chylomicrons can’t be made?
Abetalipoproteinemia
What is the name of oily stool that can result if any problems arise in regard to pancreatic enzyme secretions, bile acid secretions, emulsification, micelle formation, diffusion of lipids into epithlieal cells, chylomicron formation, transfer of chylomicrons into the lymph?
Steatorrhea
What is the overlying theme for Panceratic insufficiency, ZES, Pancreatitis?
A. Gastin secreting tumor of pancreas
B. Impaired HCO3 and enzyme secretions
C. Failure to secrete proper amounts of pancreatic enzymes
D. Improper acidity of duodenum contents
Improper acidity of duodenum contents
Explain what causes Small Intestinal Bacterial Overgrowth (SIBO) to happen, so that SIBO leads to the bacteria deconjugating bile salts early and impairing miclle formation. Hint 2 main causes
What substances do we look for in the breath to help diagnose SIBO?
- Too little gastric secretion
- Dysmotility of small intestine
Detects: Methane and Hydrogen
Which of the following vitamins are mostly absorbed via Na-dependent cotransporter? (select all that apply)
A. Vitamin B12
B. Vitamin C
C. Vitamin A and Vitamin D
D. Vitamin B1, B2, B6
Vitamin B1, B2, B6
Vitamin C
- Fat soluble vitamins ADEK, are absorbed in a similar fashion as lipids*
- Water soluble vitamins utilize the Na-dependent cotransporter EXCEPT for B12*
Which of the following vitamins is a maverick when it comes to vitamin absorption?
A. Vitamin B12
B. Vitamin C
C. Vitamin A and Vitamin D
D. Vitamin B1, B2, B6
Vitamin B12
- R protein, IF, Transcobalamin II
In what location does B12 become bound to IF?
A. Mouth
B. Stomach
C. Duodenum
D. Jejunum
E. Ileum
Duodenum
In what location is B12 exit the GI?
A. Mouth
B. Stomach
C. Duodenum
D. Jejunum
E. Ileum
Ileum
Pernicious anemia is caused by failure of RBC maturation when vitamin B12 is deficient. Vitamin B12 is defiecient when the stomach does not produce enough IF. What are 2 common causes that lead to reduction in the amount of IF?
- Atrophic gastritis: chronic inflammation of the stomach mucosa destroys parietal cells
- Autoimmune Metaplastic Atrophic Gastritis: Immune system attacks IF protein or gastric parietal cells
In which of the following locations is iron absorbed?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
Duodenum
In which of the following locations does the final starch breakdown occur via brush border enterocytes?
A. Stomach
B. Duodenum
C. Jejunum
D. Ileum
Jejunum
IRon binding occurs in the duodenum. ________ absorbs it from the gut, ________ transfers it to liver, spleen, or bone marrow where its stored in macrophages bound to _______.
IRon binding occurs in the duodenum. Ferroportin absorbs it from the gut, Transferrin transfers it to liver, spleen, or bone marrow where its stored in macrophages bound to Ferritin.
The small intestine and colon absorb large quantities of electrolytes and water, but epithelial cells lining the crypts also secrete fluid and electrolytes. The first step is absorption of solute THEN water, which happens in proportion to each other. What causes solute and water absorption to occur in proportion to each other?
A. Absorbate is always hypertonic
B. Absorbate is always hypotonic
C. Absorbate is always isotonic
D. None of the above
Absorbate is always isotonic
Which of the following accurately respresents the electrolyte absorption or secretion that occurs in the jejunum?
A. Sodium absorption
B. Sodium absorbed and HCO3 secreted
C. Sodium absorbed, K+ secreted
Sodium absorption
Which of the following accurately respresents the electrolyte absorption or secretion that occurs in the ileum?
A. Sodium absorption
B. Sodium absorbed and HCO3 secreted
C. Sodium absorbed, K+ secreted
Sodium absorbed and HCO3 secreted
Which of the following accurately respresents the electrolyte absorption or secretion that occurs in the colon?
A. Sodium absorption
B. Sodium absorbed and HCO3 secreted
C. Sodium absorbed, K+ secreted
Sodium absorbed, K+ secreted
Here’s stuff about Cholera
Cool
- increase cAMP increase Cl- secretion
- sodium follows chloride, and water follows sodium HELLO MASsive Diarrhea
