Insulin, Glucagon, And Metabolic Feedback Loops

Back to: ZOOLOGY 400 Level

Welcome to class!

Hi there, superstar! I’m so happy to have you here today. Ever wondered how your body knows when to store food and when to use it — like how you feel energised after eating amala or tired when you skip lunch? That’s your body’s way of managing sugar and energy using hormones like insulin and glucagon. Today, we’re talking about Insulin, Glucagon, and Metabolic Feedback Loops — let’s make it sweet and simple!

Insulin, Glucagon, And Metabolic Feedback Loops

Your body constantly checks the level of glucose (sugar) in your blood. Glucose is a major source of energy, especially for your brain and muscles. But it must stay within a safe range — not too high, not too low.

This balance is maintained by two powerful hormones from the pancreas:

Insulin

Glucagon

They work like a team, using a feedback loop to maintain homeostasis — a stable internal environment.

Insulin: The Sugar-Storing Hormone

After you eat — especially carbs like rice, bread, or yam — your blood sugar rises. That’s when the pancreas releases insulin.

Insulin’s job is to:

Help your body cells absorb glucose from the blood.

Tell the liver and muscles to store excess glucose as glycogen.

Reduce the amount of sugar in the blood to a normal level.

Without enough insulin, glucose can’t enter cells, and blood sugar stays too high — a condition known as diabetes mellitus.

Glucagon: The Sugar-Releasing Hormone

When you’ve not eaten for a while or you’re fasting, your blood sugar drops. The pancreas then releases glucagon.

Glucagon’s job is to:

Tell the liver to break down glycogen back into glucose.

Release that glucose into the bloodstream to keep your energy up.

Make sure your brain and muscles still get the fuel they need.

Metabolic Feedback Loop

This process is a classic negative feedback loop — when something goes too far, the body brings it back to normal.

If glucose goes too high, insulin is released to lower it.

If glucose goes too low, glucagon is released to raise it.

It’s like having a smart fuel regulator inside your body!

Example: Think of insulin and glucagon as the generator operator and fuel manager in a Nigerian home. When there’s enough fuel (glucose), insulin stores it safely. When fuel runs low, glucagon makes sure the stored fuel is released so the lights (your body) don’t go off.

Summary

1. Insulin and glucagon are hormones from the pancreas.
2. Insulin lowers blood sugar by helping cells absorb glucose and storing it as glycogen.
3. Glucagon raises blood sugar by converting glycogen back to glucose.
4. These two hormones work in a negative feedback loop to maintain glucose balance.
5. This process is key to energy regulation and preventing diseases like diabetes.

Evaluation

1. What organ produces insulin and glucagon?
2. What does insulin do in the body?
3. When is glucagon released and what does it do?
4. Define a negative feedback loop using glucose control.
5. What can happen if insulin is not produced properly?

You did absolutely fantastic today! You’ve just learnt how your body keeps your sugar levels in check with two smart hormones — and that’s real biology power! Keep learning, keep growing, and remember that with Afrilearn, you’re not just studying — you’re preparing to change the world. You’ve got this!