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Dental Physio > GI - Pt 4 Digestion > Flashcards

GI - Pt 4 Digestion Flashcards

1
Q

T/F

Gastrin is a great digestive enzyme

A

False

Gastrin does not digest anything. It is an endocrine hormone.

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2
Q

Histological Enterocyte function

  • Contains Folds of []
  • [] - which are longest in the dueodenum and shortest in the ileum
  • Structure
    • [] Cells
    • [] cells produce mucus
    • Apical surface contains [] brush b order
A
  • Contains Folds of Kerkring
  • Villi - which are longest in the dueodenum and shortest in the ileum
  • Structure
    • Columnar Cells
    • Goblet cells produce mucus
    • Apical surface contains microvilli brush border
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3
Q

The tips of enterocytes are borderline [] and are easily [] off.

A

The tips of enterocytes are borderline ischemic and are easily abraided off.

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4
Q

T/F

Gastrectomy has a greater effect on gastric stomach digestion than on intestinal digestion/absorption

A

False

gastrectomy often has a greater indirect effect by causing defective intestinal digestion and absorption.

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5
Q

The most absorption occurs in the [] []

A

small intestine

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6
Q

Usually the principle source of calories in the diet = []

A

carbohydrates

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7
Q

[] and [] are indigestible due to [] glycosidic linkages

A

Fiber and Cellulose are indigestible due to B-1,4 glycosidic linkages

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8
Q

The greatest amount of carbohydrate ingested is in the form of [].

A

starch

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9
Q
  • [] are long, unbranched chains of glucose with à-1,4 linkages
  • [] have multiple à-1,4 linkages with branches at []
A
  • Amylose are long, unbranched chains of glucose with à-1,4 linkages
  • Amylopectin have multiple à-1,4 linkages with branches at à-1,6
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10
Q

T/F

We need à-amylase for digestion?

A

False

It is not essential, for digestion.

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11
Q

Salivary à-amylase

  • Secreted by the [] gland
  • converts starch to [] and []
  • not required, but ends up being [] of carbohydrate digestion
  • Continues to work in somach fundus until []
A
  • Secreted by the parotid gland
  • converts starch to maltose and oligosaccharides
  • not required, but ends up being 50% of carbohydrate digestion
  • Continues to work in stomach fundus until acidified
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12
Q

Pancreatic à-amylase

  • Identical to [] amylase
  • Completes activity within 10 minuyutes after chyme enters the []

Intestinal amylase - identical to [] amylase

A
  • Identical to salivary amylase
  • Completes activity within 10 minutes after chyme enters the duodenum

Intestinal amylase - identical to salivary amylase

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13
Q

à-Amylase

  • hydrolyzes [] linkages
  • Spares [] linkages and terminal [] linkages
A
  • hydrolyzes à 1-4 linkages
  • Spares à 1-6 linkages and terminal à 1-4 linkages
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14
Q
  • Digestion by à-Amylase results in [], [] and []-[]
A

Digestion by à-Amylase results in maltose, maltotriose and à-limit-dextrans

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15
Q

Many brush border enzymes have []-[] [] - indicating that they may hve more than one giestive activity.

A

Cross Over Activity

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16
Q

[] (or []) on the brush border only goes after à 1-6 linkages

A

Isomaltase (or à-dextrinase) on the brush border only goes after à 1-6 linkages

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17
Q

Sucrase converts Sucrose into [] and []

A

Sucrase converts Sucrose into glucose and Fructose

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18
Q

Isomaltase (à-Dextrinase) - converts [] and other branch point residues to Glucose by acting on [] glycosidic linkages…highest activity is in the [] and []

A

Isomaltase (à-Dextrinase) - converts Isomaltose and other branch point residues to Glucose by acting on à-1,6 glycosidic linkages…..highest activity is in the jejunum and ileum

19
Q

Any enzyme that produce free glucose is considered to have [] activity

A

Maltase

20
Q
  • Maltase converts [] or [] to glucose by actin on [] glycosidic linkages
  • Maltotriase converts [] to glucose by acting on (terminal) [] glycosidic linkages
A
  • Maltase converts maltose or maltotriose to glucose by actin on à-1,4 glycosidic linkages
  • Maltotriase converts maltotriose to glucose by acting on (terminal) à-1,4 glycosidic linkages
21
Q

Maltase-Glucoamylase Complex

  • Primarily an [] enzyme
  • 2 different enzymes
    • Digest either [] or [] linkages
  • Exhibits [] activity
  • Highest activity in the []
  • Considered to be an [] (acts on terminal 1-4 linkages)
A
  • Primarily an à-Glucosidase enzyme
  • 2 different enzymes
    • Digest either à 1-4 or à 1-6 linkages
  • Exhibits Maltase activity
  • Highest activity in the ileum
  • Considered to be an exoglucosidase (acts on terminal 1-4 linkages)
22
Q

B-Galactosidase (or []) acts on [] linkages, converting [] to [] and []

A

B-Galactosidase (or lactase) acts on B-1-4 linkages, converting lactose to glucose and galactose

23
Q
  1. Only monosaccharides may be absorbed [] (minor component)
  2. Most monosaccharide absorption occurs via [] [] Trnasport mechanisms coupled thorugh the movements of []
A
  1. Only monosaccharides may be absorbed passively (minor component)
  2. Most monosaccharide absorption occurs via Secondary Active Trnasport mechanisms coupled through the movements of Na+
24
Q

Monosaccharide Absorption

  • [] and [] compete for the same active uptake system
  • []/[] carriers bring in Na+ and Glucose from the lumen into the enterocyte.
    • 2 Na+/[] cross the apical membrane
  • [] transporter moves glucose across the basolateral membrane
A
  • Glucose and galactose compete for the same active uptake system
  • SGLT-1/2 carriers bring in Na+ and Glucose from the lumen into the enterocyte.
    • 2 Na+/glucose cross the apical membrane
  • Glut-2 transporter moves glucose across the basolateral membrane
25
Q

Fructose uses the [] carrier protein to cross the apical membrane of an enterocyte

A

GLUT-5

26
Q

Exopeptidases remove one [] [] at a time from the C-terminal end

A

amino acid

27
Q
  • Pepsin is an []
    • hydrolyzes [] peptide bonds
A
  • Pepsin is an endopeptidase
    • hydrolyzes interior peptide bonds
28
Q

Pancreatic Proteases

  • released from pancrease as inactive [] precursor
  • Trypsinogen is converted to [] by [] in the brush border
  • Trypsin then converts the following
    • Chymotrypsinogen –> []
    • Proelastase –> []
    • Procarboxypeptidase –> []
  • proteases [] each other as their route of inactivation
A
  • released from pancrease as inactive zymogen precursor
  • Trypsinogen is converted to trypsin by enteropeptidase in the brush border
  • Trypsin then converts the following
    • Chymotrypsinogen –> chymotrypsin
    • Proelastase –> Elastase
    • Procarboxypeptidase –> Carboxypeptidase
  • proteases digest each other as their route of inactivation
29
Q

Trypsin, Chymotrypsin, and Elastase are all []

A

endopeptidases

30
Q

What are the 3 exopeptidase pancreatic enzymes?

A

Aminopeptidase

Carboxypeptidase A

Carboxypeptidase B

31
Q

How are all amino acids absorbed through the basolateral membrane of an enterocyte?

A

Through some unknown carrier protein

32
Q

What structure/mechanism breaks down amino acids even further once they cross the apical membrane into the enterocyte?

A

Lysozymes as Cytoplasmic Peptidases

33
Q
  1. How many amino acid transporters do we find on the apical membrane of enterocytes, that need require specific “types” of amino acids?
    1. What molecule is coupled with amino acids for transport?
    2. What are the different “types” of transporters?
A
  1. 4
    1. Na+
    2. Basic Amino Acids, Neutral Amino acids, acidic amino acids, Imino Acids
34
Q
  • Non specific amino acids transport, located on the apical membrane of enterocytes, are coupled with [] for transport
A

Na+ ​

35
Q

Di and Tri peptides croos the enterocyte apical membrane through the [] transporter

A

Pep T1

36
Q

[] is a proton and amino acid transporter located on the [] membrane of eneterocytes

A

hPAT-1 is a proton and amino acid transporter located on the apical membrane of eneterocytes

37
Q

Duodenal receptors respond to fat by activating release of[] and neural reflex slows [] []

A

Duodenal receptors respond to fat by activating release of CCK and a neural reflex that slows gastric emptying

38
Q
  • 10% of fats within the stomach are hydrolyzed by [] []
    • Its optimum pH is around [] +/- 1
A
  • 10% of fats within the stomach are hydrolyzed by Lingual lipase
    • Its optimum pH is around 5 +/- 1
39
Q

Bile [] fats and lipid within the intestine

A

emulsifies

40
Q
  • Pancreatic Secretions act as detergents and enzymes in fat digestion
    • [] - acts in intestine and cells
    • [] & [] [] - water soluble
    • Pancreatic Co-Lipase - has []activity with Pancreatic Lipase
A
  • Pancreatic Secretions act as detergents and enzymes in fat digestion
    • Phospholipase A2 - acts in intestine and cells
    • Pancreatic & Intestinal Lipase - water soluble
    • Pancreatic Co-Lipase - has potentiation activity with Pancreatic Lipase
41
Q

Micelles

  • surface covered with [] []
  • Fuse with lipid bilayer of enterocyte and [] their contents into cell cytoplasma
A
  • surface covered with bile salt
  • Fuse with lipid bilayer of enterocyte and release their contents into cell cytoplasma
42
Q
  • Bile Salts are [] reabsorbed in the Proximal intestine
  • Bile Salts are [] reabsorbed in the distal intestine
A
  • Bile Salts are passively reabsorbed in the Proximal intestine
  • Bile Salts are actively reabsorbed in the distal intestine
43
Q

Steatorrhea

  • Causes:
    • [] deficiency - leading to a failure to emulsify fats
    • Absence of pancreatic secretions like []
    • [] disease
A

Steatorrhea

  • Causes:
    • Bile deficiency - leading to a failure to emulsify fats
    • Absence of pancreatic secretions like lipase
    • Whipples disease

Dental Physio (36 decks)

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