5.3.2 Control of Blood Glucose Concentration

What controls the concentration of glucose in the blood?

The pancreas controls the concentration of glucose in the blood.

Why must blood glucose be kept within a certain limit?

Because glucose is needed by cells for respiration.

What happens when you eat foods containing carbohydrates?

Glucose levels in the blood increase.

What happens if blood glucose levels are too high?

The pancreas produces insulin, which binds to target cells and causes glucose to move into muscle cells for respiration or be converted into glycogen in the liver for storage, reducing blood glucose levels.

What happens if blood glucose levels are too low?

The pancreas produces glucagon, which binds to liver cells, causing glycogen to be broken down into glucose and released into the blood, increasing blood glucose concentration.

How is blood glucose concentration kept constant?

By insulin and glucagon working in a negative feedback loop: when glucose levels rise or fall, a hormone is secreted to oppose the change.

Why can't one hormone act continuously in blood glucose regulation?

Because once blood glucose reaches the correct concentration, the other hormone is produced to cause the opposite effect.

What is Type 1 diabetes?

A condition where the pancreas cannot produce enough insulin, causing blood glucose to rise to potentially fatal levels.

How is Type 1 diabetes treated?

With insulin injections at meal times, limiting intake of simple carbohydrates, and research into pancreas/pancreatic cell transplants and genetically engineering pancreatic cells.

What is Type 2 diabetes?

A condition where body cells no longer respond to insulin properly, leading to high blood glucose levels.

What increases the risk of Type 2 diabetes?

Obesity is a major risk factor.

How can Type 2 diabetes be treated?

By reducing intake of simple carbohydrates, losing weight, increasing exercise, and taking drugs that help insulin work more effectively or reduce glucose absorption in the gut.