Diabetes mellitus
- ICSE Class 10, Unit 3 Human Anatomy and Physiology
Diabetes mellitus is a disorder in which blood sugar stays too high, because the body makes too little insulin or does not respond to it.
Insulin is made in the pancreas, by small groups of cells called the islets of Langerhans. It helps the liver and muscles take sugar out of the blood. Without enough insulin, sugar piles up in the blood. Some of it spills into the urine.
- Signs: sugar in the urine, passing urine again and again, strong thirst, and feeling tired.
- Care: a controlled diet, regular exercise, and medicine or insulin as a doctor advises.
Do not mix it up with diabetes insipidus. That one is caused by too little ADH from the pituitary. It brings a lot of watery urine, but blood sugar stays normal.
A small example
In a healthy person, a sweet snack raises blood sugar for a short while. Insulin brings it down within a few hours. In a person with diabetes mellitus, it stays high for much longer.
Where marks go
The 2024 ICSE Biology paper asked for the gland behind each type of diabetes. The marking scheme gives the pancreas for mellitus and the pituitary for insipidus. CISCE's 2024 Biology report lists these glands among the concepts candidates got confused.
In 2025, the paper asked for the insulin chain in order: high blood sugar, insulin release, glucose uptake, lower blood sugar. CISCE's 2025 report names "random orders" as the error. Think cause then effect. See how to write answers that earn full marks.
Sources
Facts last checked against these sources on 30 September 2026.
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