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Flashcards in PI - Glucose Metabolism Deck (16):
1

Learning Outcomes (for general perusal)

  1. Monitor glucose levels in the blood after ingestion of different carbohydrate meals
  2. Distinguish between the absorption of simple and complex carbohydrates from the gut
  3. Discuss the influence of fat or protein has on glycaemic responses
  4. Describe how exercise influences blood glucose levels
  5. Describe the hormonal control of blood glucose

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2

 How should Blood Glucose be measured?

  1. Ensure hands are clean 
  2. Insert a test strip into the meter in the direction of the arrow until the meter beeps
  3. To collect blood
    1. Collect from non dominant hand
    2. Ensure hand is warm
    3. Have hand below heart level
    4. to help blood flow, massage across palm and to base of finger
  4. Put lancet in sharps bin
  5. touch blood to the end of the test strip

3

Protocol 1: Control- No food or fluid intake, measure blood glucose every 15 mins

Protocol 2 : Effects of drinking a glucose solution- drink appropriate vol and test blood glucose every 15mins

Protocol 3: Complex Carbohydrate - Eat appropriate weight of white bread, measure glucose every 15mins

Protocol 4: Complex Carb with Fat - Crisps and measure every 15mins

Protocol 5: Glucose Solution in the mouth - roll mouthfuls in the mouth, then spit out, measure blood glucose every 15 mins

Protocol 6: Drinking Glucose solution followed by exercise - drink appropriate volumes, 15mins later after recording blood glucose, exercise as hard as possible on a cycle for 15mins, then measure blood glucose every 15mins

 

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4

  1. In which regions of the body are Carbs digested and absorbed?
  2. Where does most digestion and absorption occur?

  1. Small intestine. Pancreas secretes amylase and lipase into duodenum, bile released from gall bladder. Final stages at epithelial surface. 
  2. Jejunum

5

  1. What substances are absorbed from the stomach?

simple sugars, AAs, some fat soluble substances

(not very much is absorbed here)

6

What factors influence gastric emptying?

The consistency and nature of digested food

Distention of walls (plus nervous and hormonal inputs) will increase gastric motility

Fat DELAYS gastric emptying

7

What factors influence the rate of carbohydrate absorption from the small intestine?

Decrease:  the nature of the starch and sugars, and the presence of vegetable proteins, fats, viscous fibre, and antinutrients, including lectins and phytates

 

Microvilli contain enzymes that convert disaccharides to monosaccharides for absorption

ParaS - stimulates insulin release

Symp - stimulates glucagon release

8

By what cellular transport mechanisms is glucose absorbed from the small intestine?

Glucose and galactose

Via Secondary Active Transport

The Na+/K+ ATPase on the basolateral membrane

This process is Na+ Dependent and relies upon a Na+ cotransporter carrier molecule in the luminal epithelial membrane to move monosaccharides against the concentration gradient

THEN Facilitated diffusion across the basolateral membrane

The high intracellular concentrations of monosaccharides generated during absorption generate the concentration gradients required for these nutrients to diffuse across the basolateral membrane into the mucosal capillaries.

For all monosaccharides, this process occurs via facilitated diffusion linked to a carrier protein (GLUT2) to increase the rate of transport through the lipid membrane. 

9

Describe what happens to glucose after it arrives in the blood stream following gut absorption

33% muscle and fat tissue

33% RBC and NS

34% to liver

 

10

What does the liver do when presented with a glucose load?

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 liver will store sugar, or glucose, as glycogen for a later time when your body needs it. The high levels of insulin and suppressed levels of glucagon during a meal promote the storage of glucose as glycogen. liver will store sugar, or glucose, as glycogen for a later time when your body needs it. The high levels of insulin and suppressed levels of glucagon during a meal promote the storage of glucose as glycogen.

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11

List the hormones that play a role in glucose metabolism

 

Which is the most important in regulating blood glucose after absorption of a glucose load?

Too high =  it is brought back down by insulin.

 Too low = it is brought back up by glucagon.

Adrenaline, noradrenaline, cortisol and growth hormone also raise blood glucose.

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12

What type of meal would it be best for a diabetic to eat?

Bread?

13

Provide a physiological explanation for why blood glucose resilt of drinking a glucose solution differed from those obtained after simply rinsing the mouth with the same glucose solution?

Not absorbed as much?

14

Physiological explanation for difference in blood glucose on ingesting white bread and ingesting crisps?

15

Physiological explanation for difference in blood glucose on drinking glucose solution and ingesting white bread?

16

Physiological explanation for difference in blood glucose on drinking glucose solution and drinking it followed by exercise?

Glucose sinks

Glucose removed from bloodstream by exercise

Glucose stores mobilised

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