Blood Glucose Regulation

What is glucose?

Sugar in your blood that your cells use for energy.

What organ makes insulin and glucagon?

The pancreas

What does insulin do?

Helps glucose enter cells and helps the body store extra sugar.

What does glucagon do?

Tells the body to raise blood sugar when it’s low (by telling the liver to release or make glucose).

What is the liver’s job in blood sugar control?

It’s the sugar storage closet (stores glycogen) and sugar factory (can make new glucose).

After you eat, blood sugar goes (up/down)?

Up

After you eat, which hormone increases?

Insulin

What does insulin tell body cells (muscle/fat) to do after eating?

Take in glucose from the blood.

What does insulin tell the liver to do after eating?

Store extra glucose for later.

Between meals/overnight, blood sugar goes (up/down)?

Down

Between meals/overnight, which hormone increases?

Glucagon

What is Glycogenesis?

Making glycogen (glucose → glycogen). (“Store sugar”)

Glycogenesis happens most when…

After eating, when insulin is high.

What is Glycogenolysis?

Breaking glycogen (glycogen → glucose). (“Open storage”)

Glycogenolysis happens most when…

Fasting/between meals, when glucagon is high.

What is Glycolysis?

Breaking glucose to make energy (ATP). (“Burn sugar”)

Glycolysis happens most when…

Cells need energy; commonly after eating when glucose is available.

What is Gluconeogenesis?

Making new glucose from non-sugar materials. (“Make sugar from scratch”)

Gluconeogenesis happens most when…

Longer fasting / low carbs, when glucagon is high.

What is Lipolysis?

Breaking fat into fatty acids for fuel. (“Use stored fat”)

Lipolysis happens most when…

Fasting / low insulin.

What is Ketogenesis?

Making ketones from fat (alternative fuel).

Ketogenesis happens most when…

Long fasting or not enough insulin.

What is diabetes?

Blood sugar stays too high because insulin is missing or not working well.

Type 1 diabetes: what goes wrong?

The immune system destroys insulin-making cells → little/no insulin.

Type 2 diabetes: what goes wrong?

Cells become insulin resistant (don’t respond well).

Insulin’s overall message

Use glucose + store energy.

Glucagon’s overall message

Release glucose + make glucose.

Insulin increases: glycogenesis or glycogenolysis?

Glycogenesis

Glucagon increases: glycogenesis or glycogenolysis?

Glycogenolysis

Insulin increases or decreases gluconeogenesis?

Decreases

Glucagon increases or decreases gluconeogenesis?

Increases

Insulin increases or decreases ketogenesis?

Decreases

Glucagon (and fasting) increases or decreases ketogenesis?

Increases (especially with long fasting).

Where are alpha and beta cells found?

In the pancreas

What do beta (β) cells secrete?

Insulin

What do alpha (α) cells secrete?

Glucagon

Which hormone lowers blood glucose?

Insulin (beta cells)

Which hormone raises blood glucose?

Glucagon (alpha cells)

Alpha and beta cells act as what roles in the control system?

Sensor + control center (they detect glucose and release hormones).

Why might measuring plasma insulin help tell Type 1 vs Type 2?

Type 1 usually has low insulin, Type 2 often has normal/high (early).