Exam 4: Lecture 57: Digestion and Absorption of Carbohydrates Flashcards

1
Q

What is digestion?

A

Chemical and mechanical breakdown of ingested food into absorbable molecules

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2
Q

What is absorption?

A

Movement of macronutrients, water, electrolytes from intestinal lumen into blood

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3
Q

What are the two paths of absorption?

A

Transcellular and paracellular

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4
Q

What is the difference between transcellular and paracellular absorption?

A

Transcellular crosses the luminal membrane through passive diffusion or transporters.
Paracellular moves substances across tight junctions between intestinal epithelial cells

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5
Q

Folds of Kerckring are found where?

A

In the intestinal mucosa

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6
Q

Why are there Folds of Kerckring with microvilli in the intestinal mucosa?

A

Increase surface area, slows digesta movement

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7
Q

Which portion of the small intestine have the longest villi?

A

Duodenum

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8
Q

What constitutes the brush border?

A

The microvilli that line the surface of epithelial cells

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9
Q

What is the turnover rate for gastric epithelial cells?

A

3-6 days

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10
Q

What species have a natural diet high in cellulose?

A

Horses, cattle, and sheep

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11
Q

What is the main carbohydrate in grain?

A

Startch

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12
Q

Chickens and pigs are usually fed a commercial diet high in what?

A

Grain/startch

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13
Q

What type of natural diet do dogs have?

A

Omnivore - do well with starch and some soluble fiber

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14
Q

What is the main carb source for cats on a prey diet?

A

Glycogen

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15
Q

What is the primary source of energy for most cells?

A

Glucose

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16
Q

What are the three ways that glucose is supplied in the diet?

A
  • Monosaccharides
  • Disaccharides
  • Polysaccharides
17
Q

Glucose, fructose, galactose, and ribose are examples of what type of structure?

A

Monosaccharides

18
Q

Sucrose, Maltose, and lactose are examples of what type of structure?

A

Disaccharides

19
Q

Starch, cellulose, glycogen, and hemicellulose are all examples of what structure?

A

Polysaccharides

20
Q

All ingested carbohydrates must be in which structural form to be absorbed?

A

Monosaccharides

21
Q

Which species have alpha-amylase in salivary glands and pancreas?

A

Pigs and humans

22
Q

Which enzyme cleaves the internal linkages of amylase?

A

Alpha-amylase

23
Q

Glucoamylase cleaves what portions of amylose or glycogen?

A

Linear or branched portions

24
Q

What enzyme cleaves oligosaccharides?

A

alpha-dextrinase

25
Q

Which species consumes a natural diet in cellulose?
A. Chickens
B. Dogs
C. Horses

A

C

26
Q

Sucrase breaks down sucrose into what two molecules?

A

Fructose and Glucose

27
Q

Lactase breaks down lactose into what two molecules?

A

Galactose and Glucose

28
Q

Which three main monosaccharides are absorbed?

A

Fructose, galactose, and glucose

29
Q

In order to digest cellulose or hemicellulose what do mammals need?

A

Microbial enzymes

30
Q

The absorption of monosaccharides is dependent on what ion gradient?

A

Na+

31
Q

Which transporter transports both glucose and galactose?

A

SGLT 1

32
Q

Fructose is transported from the lumen by what transporter?

A

GLUT 5 - fructose-specific

33
Q

Which transporter is responsible for transporting glucose, fructose, and galactose from the enterocyte into the blood?

A

GLUT 2

34
Q

When a carbohydrate is not able to be digested or absorbed, what happens to it?

A

Remains in the lumen, pulls water, causes osmotic diarrhea

35
Q

Which enzyme will cleave bonds of oligosaccharides released from starch?
A. alpha-amylase
B. maltase
C. alpha-dextrinase

A

C