Endocrine Pancreas Flashcards Preview

Phys: Endocrine > Endocrine Pancreas > Flashcards

Flashcards in Endocrine Pancreas Deck (53):
1

What is the function of the pancreas?

1. Both an endocrine and exocrine gland
A. Exocrine pancreas
-99% of gland
B. Endocrine pancreas
-1% of gland

2

What is the primary role of the pancreatic hormones?

1. Primary role is to maintain appropriate basal level of glucose in blood
A. 70-90 mg/dl
2. Balance accomplished by integration of glucose metabolic activity of liver, muscle and adipose tissue

3

What are the pancreatic hormones?

insulin and glucagon

4

What happens to glucose after a meal?

1. muscle storage for later use: glycogen
2. Energy for muscle and other tissue
3. Storage as fat (triglycerides)
4. Excretion in urine with high blood sugar
5. Energy for CNS
6. Liver storage for later use: glycogen

5

What is glycogenesis?

glucose -> glycogen

6

What is Glycogenolysis:

glycogen -> glucose

7

What is gluconeogenesis?

amino acids -> glucose

8

What is lipogenesis?

fatty acids & glycerol -> triglycerides

9

What is lipolysis?

triglycerides -> fatty acids & glycerol

10

What cells of the pancreas function as endocrine cells?

1. Pancreatic Islets
A. Alpha – glucagon
B. Beta – insulin
C. Delta
D. F cells

11

What is the function of the delta cells?

1. Secrete somastatin

12

What is the function of the F cells?

Secrete pancreatic polypeptide

13

What is the function of somastatin?

A. Inhibits glucagon, insulin & panc polypeptide secretion
B. Slows the rate of nutrient entry into cells

14

What is the function of glucagon?

1. Stimulates liver to break down glycogen
2. Increase blood glucose
3. Secreted during low blood glucose level

15

What is the function of insulin?

1. Decrease blood glucose
2. Secreted during high blood glucose level
3. Stimulates uptake of glucose by cells
4. Promotes muscle/adipose cells to take up glucose
5. Synthesis of glycogen in muscle/liver
6. Reduces lipolysis

16

What is the function of C peptide?

1. Connection between the A and B chains of the insulin structure. provides an index of beta cell function for pts who are receiving exogenous insulin. Half life of insulin is 5 mins; most is destroyed by proteases after glucose is transported.

2. provides an index of beta cell function for pts who are receiving exogenous insulin. Half life of insulin is 5 mins; x
3. Measured by RIA

17

Where is the highest concentration of insulin receptors?

1. Insulin receptors are present in almost all cell membranes
A. Highest concentration in liver, muscle, adipose tissue

18

What is the chain of events once insulin binds to the receptor proteins?

Stimulates a chain of events -> increase in number of glucose transport proteins in target cell membranes -> improved movement of glucose from plasma into cell cytosol

19

How does insulin affect the number of insulin receptors on cells?

Insulin increases the number of insulin? receptors

20

Where are GLUT-4 transporter proteins?

Muscle & fat cells contain a type of insulin-sensitive glucose transporter protein called GLUT-4

21

How does the binding of insulin affect the GLUT-4 transporters?

1. Normally, a few GLUT-4 transporters are in the cell membrane
2. Binding of insulin causes an recruitment of other GLUT-4 receptors from a cytoplasmic pool

22

How does exercise affect the GLUT-4 transporters?

Exercise promotes new GLUT-4 glucose transporters and their insertion into the cell membrane, increasing the muscle cell’s ability to take in glucose

23

What happens to the GLUT-4 receptors between meals?

Between meals, the recruited receptors return to ‘storage’ within the cell

24

How many forms of glucose transporters are present?

1. GLUTs (Glucose Transporter)- accomplish transport of glucose across a cell membrane
2. Six forms of GLUTs, but only GLUT-4 can respond to insulin

25

What is the function of GLUT 1?

GLUT-1 transports glucose across the blood-brain barrier

26

What is the function of GLUT 2?

GLUT-2 is involved with glucose transfer in the kidney

27

What is the function of GLUT 3?

GLUT-3 is the main transporter of glucose into neurons

28

What is the function of GLUT 4?

GLUT-4 transporters are most abundant in cells that represent the greatest use of glucose, namely muscle and fat cells

29

What is the action of insulin on glucose?

1. IncreasesGLUT4 transporters in membranes
A. Allows glucose entry into cells
2. Increase glycogen production from excess glucose
A. Facilitates storage of glucose
3. Inhibit glycogenolysis
A. Maintains glycogen storage
4. Inhibit gluconeogenesis
A. Prevents release of glucose back into blood

30

What is the action of insulin on lipids?

1. Inhibits lipase in adipose tissue
A. Decreases lipolysis
2. Inhibits oxidation of fatty acids
A. Decreases ketone formation

31

What is the action of insulin on protein?

1. Promotes active transport of amino acids from blood into muscle tissue
A. Decreases the circulating amino acid level
B. Provides building blocks for protein synthesis with cell
2. Increases rate of amino acid incorporation into protein
3. Inhibits protein degradation

32

What is the summary of insulin action?

1. Acts on skeletal muscle, liver, and adipose tissue
2. Stimulates pathways that lead to:
A. Increased glucose use
B. Increased carbohydrate and fat storage
C. Increased protein synthesis
3. Lowers blood glucose, fatty acid, and amino acid levels

33

How does elevated blood amino acid levels affect insulin levels?

stimulate beta cells to increase insulin secretion

34

How do GI hormones affect insulin levels?

GI hormones secreted in response to the presence of food stimulate insulin secretion

35

How does the parasympathetic NS affect insulin levels?

1. Occurs with food intake
2. Induces insulin secretion

36

How does the sympathetic NS affect insulin levels?

1. Inhibits insulin secretion
2. Blood glucose levels rise

37

What are the effects of insulin?

1. Increases glucose uptake and utilization by target cells
2. Stimulates glycogen formation in skeletal muscles and liver cells
3. Stimulates amino acid absorption & protein synthesis
4. Stimulates triglyceride formation in adipose tissue

38

What are the actions of glucagon?

1. Inhibit glycolysis
2. Increase gluconeogenesis
3. Increase glycogenolysis
4. Increase beta oxidation of FA’s

39

What is the pathophys of T1 DM?

1. Autoimmune destruction of insulin-producing cells
2. Circulating autoantibodies to:
A. Islet cells (ICA)
B. Insulin (IAA)
C. Glutamic acid decarboxylase (GAD65)
D. Tyrosine phosphatases (IA2 and IA2-beta)
E. Zinc transporters (ZnT8 / SLC30A8)

40

What are T1 DM pts at risk for?

DKA

41

What is the pathophys of T2 DM?

Insulin-resistance

42

What are the risk factors for T2 DM?

Obesity, insulin insensitivity, dyslipidemia
Metabolic syndrome

43

What are the sxs of hypoglycemia when gluc < 54 mg/dl?

1. Autonomic NS stimulation sxs
Tachycardia
Palitations
Sweating
Tremulous
Nausea
Hunger

44

What are the sxs of hypoglycemia when gluc < 50 mg/dl?

1. CNS sxs
Irritability
Confusion
Blurred vision
Fatigue
Headache
Difficulty speaking

45

What is diabetes insipidus?

Insufficiency of ADH secretion

46

What are the sxs of Diabetes insipidus?

1. Large volume of hypotonic urine is excreted
2. Central
A. Trauma, disease or surgery affecting post pituitary or hypothalmus
3. Nephrogenic
A. Rare
B. Reduction in ADH receptors
4. Gestational
5. Dipsogenic
A. Defect or damage to thirst mechanism

47

What are the microvascular/macrovascular complications from T1 and T2 DM?

1. retinopathy
A. Non-proliferative
B. Proliferative
2. Cardiovascular disease -> MI
3. Cerebrovascular disease -> Stroke
4. Diabetic nephropathy

48

What glucose level is insulin secretion inhibited?

~80

49

What glucose level is glucagon, epi, growth hormone secreted?

~65-70

50

What glucose level is cortisol secreted and cognitive dysfunction appear?

~50

51

What glucose level does lethargy occur?

~35

52

What glucose level does coma occur?

~30

53

What glucose level does permanent brain damage/death occur?

~12