Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SFIV Test 2 > Pancreatic Regulation of Metabolism > Flashcards

Pancreatic Regulation of Metabolism Flashcards

1
Q

What is the role of glucokinase?

A

Converts glucose in the liver to G-6-P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the affects of insulin on the liver?

A

Increases glucokinase expression

Promotes glycogen synthesis

Promotes glycolysis

Inhibits glycogenolysis

Prevents release of glucose (represses expression of glucose-6-phosphatase)

Inhibits gluconeogenesis

Stimulates fatty acid synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does insulin inhibit gluconeogensis peripherally?

A

Inhibiting protein catabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When do liver glycogen levels peak?

A

4-6 hours after the ingestion of a meal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can the enzyme profile of the liver change in response to the composition of one’s diet?

A

High Carb content - liver increase its production of enzymes that are essential for carb metabolism and fat synthesis

High protein content - increase in enzymes essential for AA metabolism and gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is glucose uptake by skeletal muscle regulated?

A

Primarily by insulin and to a lesser extent, increase in blood glucose

Stimulates translocation of the GLUT4 transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Can glycogen in skeletal muscle be mobilized to maintain blood glucose?

A

No, muscle lacks glucose 6-phosphatase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the effect of insulin on adipose tissue during the absorptive state?

A

Stimulate glucose uptake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the effect of insulin on lipoprotein lipase?

A

Induces its synthesis in skeletal muscle and fat cells

Catalyzes breakdgown of TAGs to fatty acids and glycerol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the effect of insulin on adipose tissue?

A

Inhibitor effect on basal and hormone-stimulated lipolysis by inhibiting hormone-sensitive lipase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the most potent physiological stimulator of hormone-sensitive lipase activity?

A

Epinephrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the effect of insulin on ketogenesis?

A

Suppresses it by:

Indirectly inhibiting lipolysis in adipose tissue

Stimulating formation of malonyl CoA which blocks the transport of fatty acids into the mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the major control of hepatic ketone formation?

A

Flux of FA into the lvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is ketosis?

A

Accumulation of ketone bodies in tissue and body fluids

Can have toxic effects on tissue and cause acidosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the effect of insulin on fatty acid synthesis?

A

Stimulates de novo FA synthesis in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the effect of insulin on amino acid metabolism?

A

In skeletal muscle, insulin stimulates AA uptake and protein synthesis

Also inhibits proteolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the post-absorptive period?

A

3-5 hours after a meal, the body shifts from the use of exogenous fuel sources to endogenous reserves

18
Q

What occurs to insulin and glucagon as the duration of a fast increases?

A

Insulin levels decline and glucagon levels rise

Causes a decrease in the insulin-glucagon ratio (most important in regulating metabolic functions in the liver

19
Q

What are the two results of a decrease in circulating insulin during a fast?

A

Ensures glucose is shunted away from insulin-responsive tissue

Decreases the inhibitory influence of insulin on endogenous glucose production

20
Q

What is the primary source of glucose during a fast?

A

Liver

21
Q

What are the primary substrates for hepatic gluconeogenesis during a fast?

A

Amino acids and lactate from skeletal muscle

Lactate from RBCs

Glycerol from fat

22
Q

What two tissue mobilize glucose for other tissues and why?

A

Liver and kidneys

Both express glucose-6-phosphatase

23
Q

How does glucagon promote hepatic gluconeogenesis?

A

Increases activity of specific enzymes in the pathway

Insuring the flow of substrate to the gluconeogenic pathway by decreasing glycolytic enzymes

Promoting uptake of AAs by the liver

24
Q

What substances are involved in the peripheral regulation of gluconeogenesis?

A

Cortisol - promotes protein catabolism

Insulin - inhibits protein catabolism

25
Q

Describe the mobilization of fat reserves during fasting

A

Increase in the basal rate of lipolysis due to the removal inhibitory effect of insulin

Fatty acids are used as metabolic substrates, glycerol in used for gluconeogenesis

Increased deliver of fatty acids to the liver promotes ketogenesis

26
Q

What occurs during the first three days of a fast?

A

Glucose mobilization from the liver due to insulin-glucagon ratio decrease

Increase in lipolysis

Increase in the breakdown of skeletal muscle protein

Growth hormone increases

27
Q

What occurs about 3 days after fasting?

A

Plasma glucose, FFA, and glycerol levels stabilize

Ketones continue to increase

Sole source of glucose is gluconeogenesis

28
Q

What occurs to the basal metabolic rate during prolonged fasting?

A

Basal metabolic rate goes down, most likely due to decreased thyroid hormone activity

T3 regulates the basal metabolic rate

During a fast, T3 drops by about half

29
Q

What is the change in substrate utilization by the brain in a prolonged fast?

A

Goes from majority glucose to majority ketones

Transition to ketone metabolism has a protein sparing effect

30
Q

What are the causes of hypoglycemia?

A

Drugs that potentiate the effects of insulin (SU) or substances that interfere with gluconeogenesis (EtOH)

Insulinomas

Rapid gastric emptying

Adrenal and Pituitary insufficiency

Liver disease

31
Q

What is the response of the brain to hypoglycemia?

A

Hypothalamus activates the SNS

SNS stimulates glucagon release from pancreas

Rapid rise in circulating epinephrine levels

32
Q

What causes the symptoms associated with hypoglycemia?

A

Sympathetic activation

Neuroglycopenia

33
Q

What are counterregulatory hormones?

A

Hormones released in response to hypoglycemia

E.g. glucagon and epinephrine

34
Q

What is the principal counterregulatory hormone in restoring blood glucose levels?

A

Glucagon

35
Q

How does epinephrine protect against falling blood glucose?

A

Inhibiting glucose utilization by the muscle

Stimulating hepatic glycogenolysis and gluconeogenesis

Inhibiting insulin secretion and stimulating glucagon release

Stimulatory effect on lipolysis

36
Q

What hormones are involved in the response to prolonged hypoglycemia?

A

GH and ACTH

37
Q

What are the criteria for diagnosing DM?

A

Fasting plasma glucose >126 mg/dl

2h plasma glucose >200 during oral glucose tolerance test

AIC > 6.5

Symptoms of hyperglycemia

38
Q

What is T1DM?

A

Insulin deficiency resulting from beta cell destruction

5-10%

39
Q

What are the most serious acute metabolic complications of DM?

A

DKA and hyperosmolar hyperglycemic state

HHS is characterized by hyperglycemia, hyperosmolality and dehydration

40
Q

What is T2DM?

A

Heterogeneous group of diseases characterized by a progressive impairment of beta cell function resulting in relative insulin deficiency plus varying degrees of insulin resistance

Obesity is a major risk factor

SFIV Test 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions