BMS 302: Control of Blood Glucose Levels

What are insulin receptors?

Proteins on cell membranes that bind insulin and trigger glucose uptake.

What is glycogen?

Stored form of glucose in liver and muscles.

What is hypoglycemia?

Low blood glucose levels.

What is hyperglycemia?

High blood glucose levels.

What do β-cells of the pancreas secrete?

Insulin.

What do α-cells of the pancreas secrete?

Glucagon.

Glycogenesis – synthetic or degradative?

Synthetic (glucose → glycogen; after meal; ↓ blood glucose).

Glycogenolysis – synthetic or degradative?

Degradative (glycogen → glucose; fasting; ↑ blood glucose).

Gluconeogenesis – synthetic or degradative?

Synthetic (non-carbs → glucose; fasting; ↑ blood glucose).

Lipogenesis – synthetic or degradative?

Synthetic (glucose → fat; after meal; ↓ blood glucose).

Lipolysis – synthetic or degradative?

Degradative (triglycerides → fatty acids + glycerol; fasting; ↑ blood glucose).

Which cells need insulin for glucose uptake?

Muscle cells and adipose tissue.

Which cells do NOT need insulin for glucose uptake?

Neurons and liver cells.

Which pancreatic cells detect changes in blood glucose?

β-cells (and α-cells) of pancreatic islets.

Role of insulin in glucose transport:

Promotes facilitated diffusion of glucose into cells.

Insulin’s overall effect on blood glucose:

Decreases blood glucose levels.

Stimulus for insulin release:

Increased blood glucose after eating.

Cells that make insulin:

β-cells of the pancreas.

Which processes are stimulated by insulin?

Glycogenesis and lipogenesis.

Which processes are inhibited by insulin?

Glycogenolysis, gluconeogenesis, and lipolysis.

Glucagon’s overall effect on blood glucose:

Increases blood glucose levels.

Stimulus for glucagon release:

Low blood glucose (fasting).

Cells that make glucagon:

α-cells of the pancreas.

Processes stimulated by glucagon in the liver:

Glycogenolysis and gluconeogenesis.

When are insulin and glucagon secreted tonically?

Always — but amounts vary depending on fed vs. fasting state.

Insulin:glucagon ratio after eating:

High (insulin ↑, glucagon ↓).

Insulin:glucagon ratio during fasting:

Low (insulin ↓, glucagon ↑).

Why are glucose levels similar after an overnight vs. short fast?

Only takes 2-3 hours to get back to baseline blood glucose levels. 

Epinephrine’s overall effect on blood glucose:

Increases blood glucose levels.

Stimulus for epinephrine release:

Stress, exercise, or low blood glucose.

Organ that releases epinephrine:

Adrenal medulla.

Processes stimulated by epinephrine:

Glycogenolysis (not glycogenesis).

Symptom: Hyperglycemia – cause?

Insufficient insulin activity → high blood glucose.

Symptom: Glucosuria – cause?

Glucose exceeds renal threshold → appears in urine.

Symptom: Polyuria – cause?

Excess glucose in urine causes osmotic water loss.

Symptom: Polydipsia – cause?

Dehydration from polyuria → increased thirst.

Symptom: Acidosis (ketoacidosis) – cause?

Fat breakdown → ketone accumulation.

Type 1 diabetes – cause?

Decreased insulin production (autoimmune β-cell destruction).

Type 1 diabetes – age of onset?

Usually under 20 years old.

Type 1 diabetes – treatment?

Insulin injections.

Type 1 diabetes – other features?

Autoimmune, not obesity-related.

Type 2 diabetes – cause?

Decreased insulin receptor function (insulin resistance).

Type 2 diabetes – age of onset?

Usually over 40 years old.

Type 2 diabetes – treatment?

Diet, exercise, oral meds.

Type 2 diabetes – other features?

Associated with obesity and family history.

Insulin shock – cause?

Too much insulin → very low blood glucose.

Insulin shock – treatment?

Give glucose.

Diabetic coma – cause?

Too little insulin → very high blood glucose.

Diabetic coma – treatment?

Give insulin.

Normal fasting glucose level:

~70–100 mg/dL.

Normal 2 hours after glucose load:

Returns to baseline; no glucose in urine.

Diabetic Fasting glucose level:

126 mg/dL

Diabetic 2 hours after glucose load:

Still high; glucose present in urine.

ADA diabetes screening recommendation:

Adults ≥45 yrs or younger with risk factors.

Why ADA recommends screening:

Early detection prevents complications.

DuBois Body Surface Area Nomogram used for:

Calculating body surface area (BSA) from height and weight.

How to calculate drug dose (example):

0.3 mg/kg × 70 kg = 21 mg; with 10 mg/mL → give 2.1 mL.

Graph type for blood glucose data:

Line or bar graph (whichever fits data best).