IGCSE Biology glossary
Insulin
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Definition
A hormone produced by the beta cells of the islets of Langerhans in the pancreas when blood glucose concentration is too high. Insulin stimulates liver and muscle cells to take up glucose and convert it to glycogen for storage, lowering blood glucose levels.
What to include in an exam answer
Insulin REDUCES blood glucose. It causes glucose to be converted to glycogen and stored in the liver. In diabetes Type 1, the pancreas does not produce enough insulin. Do not confuse insulin with glucagon.
Example in context
Describe the role of insulin in controlling blood glucose levels (3 marks): When blood glucose is too high, the pancreas detects this and releases insulin. Insulin causes liver and muscle cells to absorb glucose from the blood and convert it to glycogen for storage. This lowers the blood glucose level back to normal.
Related syllabus topic
Coordination & responseRelated terms
- Homeostasis
- Negative feedback
- Tropism
- Reflex arc
- ADH
- Glucagon
- Adrenaline
- Synapse
- Neurone
- Sensory neurone
- Motor neurone
- Relay neurone
- Receptor
- Effector
- Cornea
- Iris
- Lens
- Retina
- Optic nerve
- Accommodation
- Type 1 diabetes
- Type 2 diabetes
- Hormones
- Endocrine gland
- Auxin
- Thermoregulation
- Vasoconstriction
- Vasodilation
- Sweating