Feedback regulates hormone release

The idea

The timing and amount of hormone released are regulated by feedback mechanisms: when blood sugar rises the pancreas produces more insulin, and as it falls insulin secretion is reduced.

A thermostat for sugar

A cooler switches off when a room is cold enough. The body also has ways of switching hormone release up or down.

How do you think the amount of insulin released stays right?

• The cells of the pancreas detect the blood sugar level and adjust
• A fixed amount is released at the same rate all day
• The brain counts the sugar in each meal

Up and down

Sort each step by what the blood sugar is doing.

The body adjusts

Because the pancreas detects the sugar level, the amount of insulin goes up or down to match it. This is a feedback mechanism.

The timing and amount of hormone released are regulated by feedback mechanisms. When blood sugar rises, the pancreas produces more insulin, and as it falls, insulin secretion is reduced.

Notes

The timing and amount of hormone released are regulated by feedback mechanisms: when blood sugar rises the pancreas produces more insulin, and as it falls insulin secretion is reduced.

Check yourself

What regulates the timing and amount of hormone released?

Blood sugar rises. What does the pancreas do?

Blood sugar falls. What happens to insulin secretion?

What detects a rise in blood sugar in this example?

• A fixed amount released at fixed times. The book says feedback mechanisms regulate the timing and amount.
• Feedback mechanisms — correct. Yes!
• A reflex arc in the spinal cord. A reflex arc connects input nerves to output nerves. Hormone release is regulated by feedback mechanisms.
• It reduces insulin secretion. Insulin secretion is reduced when blood sugar falls.
• It makes thyroxin. Thyroxin is made by the thyroid gland.
• It produces more insulin — correct. Yes!
• It is reduced — correct. Yes!
• It is increased. More insulin is produced when blood sugar rises, not when it falls.
• It stops at once and never restarts. The book says insulin secretion is reduced as the sugar level falls.
• The cells of the thyroid gland. The thyroid gland makes thyroxin. The cells of the pancreas detect the sugar level.
• The cells of the pancreas — correct. Yes!
• The cerebellum. The cerebellum is responsible for precision, posture and balance.