What it does
Hormones are chemical messages. Endocrine glands release them straight into the blood, which carries them to the organs they act on. This page has two parts. First, a map of the glands: tap the pineal, hypothalamus, pituitary, thyroid, thymus, adrenals, pancreas or the testes and ovaries to read which hormone each makes and what it does. Second, a feedback loop you can run: a day of blood sugar from 06:00 to 18:00. Meals push blood glucose up; the pancreas answers with insulin, which helps cells and the liver take glucose in. A run uses glucose up; the pancreas answers with glucagon, which makes the liver release some. The response undoes the change, so the level stays near a set point: that is negative feedback. Where the glucose comes from is on the digestion journey, and what cells do with it is in respiration pathways; the kidneys’ part, glucose spilling into urine when the level is very high, is in the kidney nephron filter.
Using it
- Pick a Level. Class 11 adds more hormones for each gland and names the loop as negative feedback.
- Tap a gland on the body map.
- In the loop, pick the body: healthy, insulin works weakly (cells respond poorly, a bit like type 2 diabetes), or no insulin made (like untreated type 1 diabetes).
- Tick or untick breakfast, lunch and the run. The chart redraws: glucose (black), insulin (green) and glucagon (dashed), with the usual range shaded.
- Drag the time slider. The loop diagram lights up the half that is working at that moment, and the text explains it.
Worked example
With the healthy body and all three events ticked, breakfast at 07:00 lifts glucose to a peak of about 129 mg/dL at 07:44. Insulin rises with it, and by 08:00 the level is already falling (123 mg/dL, insulin about 32 units on the model’s own scale). During the run at 16:00 the level dips to about 80 mg/dL; glucagon rises and brings it back to 90. Switch to No insulin made and the same day peaks near 218 mg/dL and spends about 9 hours above 140: without insulin, cells cannot take the glucose in. With Insulin works weakly, the peak is about 156 mg/dL and the level spends about 2 hours above 140.
Where this fits in school
Class 10 science (control and coordination) covers hormones in animals, the main endocrine glands, iodised salt and goitre, growth hormone, insulin and diabetes, and feedback control of hormone release. Class 11 biology (chemical coordination and integration) covers every gland and hormone in more detail, including glucagon and the islets of Langerhans. This page is an independent learning aid. It is not made by or connected with NCERT, and it does not copy any textbook.
Questions
Can I use this to manage diabetes? No. It is a simple teaching model with made-up rates. Real blood sugar depends on many things. Always follow a doctor’s advice.
What are the “units” of insulin on the chart? Just the model’s own scale, to show when insulin rises and falls. They are not real doses.
Is anything saved? No. Nothing you choose is stored or sent anywhere.
Where the numbers come from
- The endocrine glands, their hormones and the insulin and glucagon feedback loop: standard school biology, written by fibub in its own words.
- The blood sugar model (meal size, absorption, hormone response rates, set point 90 mg/dL, usual range 70 to 140 mg/dL) uses made-up round values for teaching. It is not a medical model and gives no doses.
- Checked in the tests: with no meals the level stays at 90; a healthy body peaks near 129 mg/dL and comes back; with no insulin it stays high for hours; each meal's glucose adds up to its set size.
- Drawings are fibub's own simple shapes. Nothing you choose is stored or sent anywhere.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-09.