Hormones
Chemical messengers like insulin and adrenaline regulating physiology.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Chemical messengers like insulin and adrenaline regulating physiology.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Hormones are chemical messengers secreted by endocrine glands into the blood and recognised by receptors on or inside target cells. They are chemically diverse: peptide hormones such as insulin, steroid hormones such as cortisol and oestrogen derived from cholesterol, and amino acid derivatives such as adrenaline and thyroxine. Water-soluble peptide hormones bind surface receptors and trigger second messenger cascades, while lipophilic steroids cross the membrane and regulate gene transcription. Hormones act at very low concentrations and their levels are controlled by negative feedback loops. They regulate metabolism, growth, reproduction, stress responses and water balance.
Key ideas: Chemical messengers carried in blood to target cells with matching receptors. Three chemical types: peptides and proteins (insulin, glucagon), steroids (cortisol, testosterone, estrogen) derived from cholesterol, and amino acid derivatives (thyroxine, adrenaline). Peptide hormones bind surface receptors and use second messengers such as cAMP; steroids cross the membrane and act on gene expression.
Common mistakes and connections: A misconception is that all hormones are proteins. Another is mixing insulin (lowers blood glucose) with glucagon (raises it). Steroid effects are slower but longer lasting than peptide effects. Links to cholesterol, signal transduction and drug action.
Typical blood glucose after a meal. Rising glucose triggers insulin release, which signals cells to take up glucose and brings the level back to baseline. The interactive lesson shows this as a live animation or chart.
Insulin released after a meal signals muscle and fat cells to take up glucose, lowering blood glucose.
Chemical messengers like insulin and adrenaline regulating physiology.
Hormones is a intermediate topic in Biochemistry, Environment & Industry. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Biochemistry, Environment & Industry first: Lock and Key vs Induced Fit, Cofactors and Coenzymes, Vitamins.
The next topics in Biochemistry, Environment & Industry are Fats and Oils and Saturated and Unsaturated Fatty Acids.
Yes. The interactive lesson includes a self-check question on Hormones, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Hormones is topic 17 of 127 in Biochemistry, Environment & Industry.
Browse all 127 topics in Biochemistry, Environment & Industry