Glucose Regulation Review

What are the two main functions of the pancreas?

• Exocrine pancreas: secretes digestive enzymes into the duodenum (acinar cells)

• Endocrine pancreas: secretes hormones into the bloodstream (islets of Langerhans)

What cells make up the islets of Langerhans and what do they secrete?

• Alpha cells → glucagon

• Beta cells → insulin

• Delta cells → somatostatin

What is the endocrine pancreas responsible for?

• Control of carbohydrate metabolism

• Regulation of blood glucose via insulin and glucagon

What are the primary actions of insulin on glucose?

• Increases glucose transport into skeletal muscle and adipose tissue

• Increases glycogen synthesis

• Decreases gluconeogenesis

What are the primary actions of glucagon on glucose?

• Promotes glycogen breakdown

• Increases gluconeogenesis

How does insulin affect fats and proteins?

• Anabolic (storage hormone)

• Promotes glucose uptake

• Promotes glycogen storage

• Prevents fat and glycogen breakdown

• Inhibits gluconeogenesis

• Increases protein synthesis

How does glucagon affect fats and proteins?

• Catabolic hormone

• Increases amino acid transport into liver

• Increases protein breakdown

• Converts amino acids into glucose precursors

How do catecholamines (epinephrine & norepinephrine) affect glucose?

Maintain blood glucose during stress

What is the effect of growth hormone on glucose?

• Increases protein synthesis

• Mobilizes fatty acids

• Antagonizes insulin

What is the role of glucocorticoids in glucose regulation?

• Essential during fasting/starvation

• Stimulate hepatic gluconeogenesis

What are key characteristics of insulin?

• Anabolic (storage hormone)

• Composed of 51 amino acids

• Synthesized in beta cells

• Promotes synthesis of proteins, carbs, lipids, nucleic acids

• Lowers blood glucose

What happens to glucose if insulin is absent?

• Glucose remains in bloodstream

• Blood becomes hyperosmolar

• Thirst center stimulated

• Fluid stays in bloodstream

• Kidneys excrete glucose → osmotic diuresis

• ↑ urine volume with fluid & electrolyte loss

Where does energy metabolism occur?

Inside the cell, producing ATP

How are carbohydrates metabolized?

• Dietary glucose → stored as glycogen (liver)

• Glucagon converts glycogen → glucose

• Excess glucose → fat storage

How are fats metabolized?

• Fats → glycerol + fatty acids

• Glycerol → glucose

• Fatty acids → ketones

• Ketones can be used as alternate energy

How are proteins involved in glucose metabolism?

Liver converts proteins → glucose via gluconeogenesis

Which tissues do NOT require insulin for glucose uptake?

• Brain

• Red blood cells

• Kidneys

• Lens of the eye

Why does blood glucose remain normal in healthy individuals?

• Insulin released at correct times and amounts

• Insulin facilitates glucose entry into cells

What is hypoinsulinism?

• Inadequate insulin production

• Results in hyperglycemia

What is the normal fasting blood glucose range?

80–105 mg/dL

What is diabetes mellitus (DM)?

• Disorder of carbohydrate, protein, and fat metabolism

• Imbalance between insulin availability and need

What mechanisms can cause diabetes?

• Absolute insulin deficiency

• Impaired insulin secretion

• Defective insulin receptors

• Inactive insulin

What are major risk factors for DM?

• Family history

• Obesity

• Age >45

• Race/ethnicity

• HTN

• Low HDL / high triglycerides

• Gestational diabetes history

• Large birth weight infants (>9 lb)

What is hypoglycemia also called?

• Insulin shock

• Insulin reaction

What typically causes hypoglycemia?

• Too much insulin or antidiabetic medication

• Missed or delayed meals

• Not eating enough

• Excessive exercise

• Alcohol

What blood glucose level defines hypoglycemia?

• Often <60 mg/dL

• Sometimes 45–60 mg/dL

• Patient-specific

When does hypoglycemia most often occur?

• Any time of day

• Commonly before meals if meals are skipped or delayed

What are early (adrenergic) symptoms of hypoglycemia?

• Diaphoresis

• Tremors

• Nervousness, jitteriness

• Tachycardia

• Palpitations

What neurologic symptoms occur with hypoglycemia?

• Slurred speech

• Confusion

• Memory lapses

• Impaired concentration

• Altered LOC

• Combative or irrational behavior

Why is hypoglycemia often confused with stroke?

• Similar symptoms:

  • Slurred speech

  • Confusion

  • Impaired coordination

• Blood glucose must be checked first

How is hypoglycemia treated if the patient is awake and alert?

Oral glucose:

• Glucose tablets

• Candy (Smarties)

• Icing gel

• Juice + sugar paste

How is hypoglycemia treated if the patient cannot swallow?

• IM glucagon

• IV dextrose (D50)

What education prevents hypoglycemia?

• Regular meals/snacks

• Match insulin to food

• Monitor glucose with exercise

• Carry fast-acting sugar

• Wear medical ID

• Avoid exercising alone

• Take meds as prescribed

• Keep routine provider visits

What are the overall goals of glucose regulation therapy?

• Prevent DKA

• Minimize hyperglycemia

• Prevent hypoglycemia

• Maintain healthy weight

• Control cholesterol & triglycerides

What are the main types of insulin?

• Rapid-acting

• Short-acting

• Intermediate-acting

• Long-acting

• Ultra-long-acting

Rapid-acting insulins (names + timing)?

• Lispro, Aspart, Glulisine

• Onset: 10–30 min

• Peak: 30 min–3 hr

• Duration: 3–5 hr

• Give with meals

Short-acting insulin (name + timing)?

• Regular insulin

• Onset: 30–60 min

• Peak: 2–5 hr

• Duration: 5–8 hr

• Give 30 min before meals

• Only insulin given IV

Intermediate-acting insulin (name + timing)?

• NPH

• Onset: 1–2 hr

• Peak: 4–12 hr

• Duration: 12–18 hr

• Needs snacks (hypoglycemia risk at peak)

Long-acting insulins (names + timing)?

• Glargine, Detemir

• Onset: 1–2 hr

• No peak

• Duration: ~24 hr

• Basal insulin (once daily)

Ultra-long-acting insulin (name)?

• Degludec (Tresiba)

• Duration: up to 42 hr

Which insulin can be given IV?

Regular insulin only

Which insulins can be mixed?

• NPH + Regular

• NPH + Rapid-acting

Which insulins should NOT be mixed?

Long-acting & ultra-long-acting insulins

Correct order for drawing up insulin?

• Clear → Cloudy

• Regular before NPH

When is hypoglycemia most likely with insulin therapy?

During peak times

One-line insulin memory trick?

• Rapid = Right now

• Regular = 30 min

• NPH = Needs snacks

• Long = Level all day

A nurse is preparing to administer insulin lispro to a patient. When should the nurse ensure the patient will eat?

A. 30 minutes after administration
B. Immediately or with the first bite of food
C. 1 hour after administration
D. At bedtime

B. Immediately or with the first bite of food

Rationale:
Lispro is a rapid-acting insulin with an onset of 10–30 minutes. Giving it without food risks hypoglycemia.

Which insulin should be administered 30 minutes before meals?

A. Insulin aspart
B. Insulin glargine
C. Regular insulin
D. NPH insulin

C. Regular insulin

Rationale:
Regular insulin is short-acting and must be given 30 minutes before meals to match glucose absorption.

The nurse is caring for a patient receiving NPH insulin. At what time is hypoglycemia most likely to occur?

A. 15 minutes after injection
B. 1 hour after injection
C. During peak activity
D. At bedtime only

C. During peak activity

Rationale:
NPH peaks 4–12 hours after administration, making hypoglycemia most likely during this time.

Which insulin provides basal glucose control with no pronounced peak?

A. Regular
B. NPH
C. Glargine
D. Aspart

C. Glargine

Rationale:
Glargine is a long-acting insulin that provides steady, 24-hour basal control with no peak.

Which insulin is appropriate for IV administration in a hospitalized patient?

A. Lispro
B. NPH
C. Glargine
D. Regular insulin

D. Regular insulin

Rationale:
Regular insulin is the only insulin approved for IV use, commonly used in DKA and HHS.

The nurse prepares to mix regular insulin with NPH insulin. Which action is correct?

A. Draw up NPH first
B. Draw up regular insulin first
C. Mix glargine with NPH
D. Shake both vials before drawing up

B. Draw up regular insulin first

Rationale:
Always draw clear before cloudy to prevent contaminating regular insulin.

A patient receives rapid-acting insulin but then refuses to eat. What is the nurse’s priority concern?

A. Hyperglycemia
B. Infection
C. Hypoglycemia
D. Insulin resistance

C. Hypoglycemia

Rationale:
Rapid-acting insulin lowers glucose quickly. Without food intake, the patient is at high risk for hypoglycemia.

Which insulin requires the patient to plan snacks to prevent hypoglycemia?

A. Aspart
B. Regular
C. NPH
D. Glargine

C. NPH

Rationale:
NPH has a pronounced peak, making scheduled meals and snacks essential.

A nurse is teaching a patient about insulin timing. Which statement indicates correct understanding?

A. “I take glargine with meals.”
B. “I take regular insulin right before I eat.”
C. “I take rapid-acting insulin when food is available.”
D. “I take NPH insulin only at bedtime.”

C. “I take rapid-acting insulin when food is available.”

Rationale:
Rapid-acting insulin must be taken immediately before meals to prevent hypoglycemia.

Which actions reduce the risk of insulin-related hypoglycemia? (Select all that apply.)

A. Eating meals at consistent times
B. Skipping meals after insulin
C. Monitoring blood glucose before exercise
D. Knowing insulin peak times
E. Mixing glargine with NPH

A, C, D

Rationale:
✔ Consistent meals, glucose monitoring, and knowing peak times reduce hypoglycemia risk.
✘ Skipping meals and mixing long-acting insulin increase risk.