NURS 2514 - W2 EXAM QUESTIONS WITH
COMPLETE ANSWERS
What is diabetes mellitus? - ANSWER A disorder of the endocrine portion of the
pancreas involving a deficiency of insulin function.
Can be:
1. Decreased secretion
2. Tissue sensitivity (ie. insulin resistance)
3. Both
Characterized by the presence of hyperglycemia.
Who does DM affect? - ANSWER 9% of the population
Prevalence is 22% in adults over the age of 20
What can diabetes mellitus result in? - ANSWER 1. Hyperglycemia
2. Increased catabolism of protein and lipid
3. Acute emergencies involving acidosis
4. Chronic complications
What do alpha (A) cells of the islets of Langerhans secrete? - ANSWER Glucagon
What do beta (B) cells of the islets of Langerhans secrete? - ANSWER Insulin
What is insulin? - ANSWER An anabolic (protein) hormone manufactured exclusively by
islet B cells, stored in vesicles, and secreted by exocytosis when needed
How does high blood glucose stimulate insulin secretion? - ANSWER 1. Glucose enters
B cells through GLUT 2 and increases cellular ATP levels through glycolysis
(metabolism)
2. ATP closes K+ channels in B cells causing the membrane potential to become more
positive (depolarized)
3. Voltage-gated Ca++ channels open in response and triggers the release of insulin
Calcium is the trigger for exocytosis of insulin
What is insulin secretion stimulated by? - ANSWER 1. Primarily high blood glucose
,2. Amino acids
3. Acetylcholine (PSNS)
What is insulin secretion inhibited by? - ANSWER 1. a-adrenergic stimulation (SNS)
2. b-blockade
What is insulin secretion matched to? - ANSWER Dietary intake and metabolic rate
What is C peptide and what can it diagnostically be used for? - ANSWER Connecting or
C peptide is the inactive part of injected insulin
- active C peptide is made by individuals themselves
- can measure C peptide to determine how much insulin they make on their own
What does insulin promote the uptake of? - ANSWER 1. aa into muscle cells for protein
synthesis (anabolic)
2. FAs into adipose tissue for TG storage
3. K+ ions (results in lowered blood potassium)
How is blood glucose regulated after meals? - ANSWER High blood glucose after meals:
1. Pancreatic B cells release insulin into the blood
2. Insulin promotes glucose disposal into cells (increased uptake)
3. Liver stores glucose as glycogen
How is blood sugar regulated between meals? - ANSWER Blood sugar lowers q2h:
1. Pancreatic A cells release glucagon into the blood
2. Glucagon breaks down glycogen into glucose and excretes it into the blood (hepatic
glucose output)
What causes type 1 DM? - ANSWER Autoimmune disease: T cell and antibody mediated
immune assault on B cells
- B cell destruction takes time
- symptoms appear acutely when >70% of B cells are eliminated
- eventually B cells are irreversibly lost and insulin secretion is nonexistent
Why are type 1 patients referred to as insulin-dependent diabetics (IDDM)? - ANSWER
Because they require lifelong exogenous insulin
Note:
, - Age of onset is <30 (juvenile diabetes)
- Represents 10% of all diabetic cases
- 50% of type 1 cases have genetic associations
Why do type 1 DM patients look sickly thin? - ANSWER Because they lack insulin which
is an anabolic hormone (lose lots of muscle and fat -- non-obese with muscle wasting)
What can you measure to determine how much B cells are left in type 1 DM? - ANSWER
C peptide
What type of hypersensitivities are occurring in type 1 DM? - ANSWER Type II
(Ab-antigen complexes) and IV (T cells destroying pancreatic B cells) simultaneously
What is the most common type of DM? - ANSWER Type 2
- 90% of all diabetics
- 80% of pts are obese (esp. at abdomen)
- 80% have a family Hx
What is the key characteristic of type 2 DM? - ANSWER Insulin resistance with
decreased insulin-stimulated glucose uptake
- cause unknown but multifactorial
- usually have more insulin than normal but don't respond to it
- insulin is not a first line of Tx
- can make lifestyle changes to control symptoms but not totally effective
What compensatory mechanisms occur in type 2 DM? - ANSWER Early stages:
1. Hepatic glucose output is increased to compensate for insulin resistance
2. Pancreas increases secretion of insulin causing hyperinsulinemia
Late stages:
1. Pancreas becomes exhausted causing defective insulin secretion and diabetes
- typically adult onset but now common in adolescence
- many cases go undiagnosed b/c of gradual onset
COMPLETE ANSWERS
What is diabetes mellitus? - ANSWER A disorder of the endocrine portion of the
pancreas involving a deficiency of insulin function.
Can be:
1. Decreased secretion
2. Tissue sensitivity (ie. insulin resistance)
3. Both
Characterized by the presence of hyperglycemia.
Who does DM affect? - ANSWER 9% of the population
Prevalence is 22% in adults over the age of 20
What can diabetes mellitus result in? - ANSWER 1. Hyperglycemia
2. Increased catabolism of protein and lipid
3. Acute emergencies involving acidosis
4. Chronic complications
What do alpha (A) cells of the islets of Langerhans secrete? - ANSWER Glucagon
What do beta (B) cells of the islets of Langerhans secrete? - ANSWER Insulin
What is insulin? - ANSWER An anabolic (protein) hormone manufactured exclusively by
islet B cells, stored in vesicles, and secreted by exocytosis when needed
How does high blood glucose stimulate insulin secretion? - ANSWER 1. Glucose enters
B cells through GLUT 2 and increases cellular ATP levels through glycolysis
(metabolism)
2. ATP closes K+ channels in B cells causing the membrane potential to become more
positive (depolarized)
3. Voltage-gated Ca++ channels open in response and triggers the release of insulin
Calcium is the trigger for exocytosis of insulin
What is insulin secretion stimulated by? - ANSWER 1. Primarily high blood glucose
,2. Amino acids
3. Acetylcholine (PSNS)
What is insulin secretion inhibited by? - ANSWER 1. a-adrenergic stimulation (SNS)
2. b-blockade
What is insulin secretion matched to? - ANSWER Dietary intake and metabolic rate
What is C peptide and what can it diagnostically be used for? - ANSWER Connecting or
C peptide is the inactive part of injected insulin
- active C peptide is made by individuals themselves
- can measure C peptide to determine how much insulin they make on their own
What does insulin promote the uptake of? - ANSWER 1. aa into muscle cells for protein
synthesis (anabolic)
2. FAs into adipose tissue for TG storage
3. K+ ions (results in lowered blood potassium)
How is blood glucose regulated after meals? - ANSWER High blood glucose after meals:
1. Pancreatic B cells release insulin into the blood
2. Insulin promotes glucose disposal into cells (increased uptake)
3. Liver stores glucose as glycogen
How is blood sugar regulated between meals? - ANSWER Blood sugar lowers q2h:
1. Pancreatic A cells release glucagon into the blood
2. Glucagon breaks down glycogen into glucose and excretes it into the blood (hepatic
glucose output)
What causes type 1 DM? - ANSWER Autoimmune disease: T cell and antibody mediated
immune assault on B cells
- B cell destruction takes time
- symptoms appear acutely when >70% of B cells are eliminated
- eventually B cells are irreversibly lost and insulin secretion is nonexistent
Why are type 1 patients referred to as insulin-dependent diabetics (IDDM)? - ANSWER
Because they require lifelong exogenous insulin
Note:
, - Age of onset is <30 (juvenile diabetes)
- Represents 10% of all diabetic cases
- 50% of type 1 cases have genetic associations
Why do type 1 DM patients look sickly thin? - ANSWER Because they lack insulin which
is an anabolic hormone (lose lots of muscle and fat -- non-obese with muscle wasting)
What can you measure to determine how much B cells are left in type 1 DM? - ANSWER
C peptide
What type of hypersensitivities are occurring in type 1 DM? - ANSWER Type II
(Ab-antigen complexes) and IV (T cells destroying pancreatic B cells) simultaneously
What is the most common type of DM? - ANSWER Type 2
- 90% of all diabetics
- 80% of pts are obese (esp. at abdomen)
- 80% have a family Hx
What is the key characteristic of type 2 DM? - ANSWER Insulin resistance with
decreased insulin-stimulated glucose uptake
- cause unknown but multifactorial
- usually have more insulin than normal but don't respond to it
- insulin is not a first line of Tx
- can make lifestyle changes to control symptoms but not totally effective
What compensatory mechanisms occur in type 2 DM? - ANSWER Early stages:
1. Hepatic glucose output is increased to compensate for insulin resistance
2. Pancreas increases secretion of insulin causing hyperinsulinemia
Late stages:
1. Pancreas becomes exhausted causing defective insulin secretion and diabetes
- typically adult onset but now common in adolescence
- many cases go undiagnosed b/c of gradual onset
