Q.What are harmones ? Give examples.

Hormones are the body's long-distance chemical messengers, released by endocrine glands straight into the blood and carried to distant target organs to coordinate and regulate physiological processes such as metabolism, growth, and the stress response.

Definition: hormones are organic chemical messenger substances, produced and secreted in small quantities directly into the bloodstream by specialised ductless (endocrine) glands. They are transported by the blood to a target organ or tissue located elsewhere in the body, where they bind to specific receptors and regulate/coordinate various physiological and biochemical activities — including growth, metabolism, reproduction, and the body's response to stress.

Examples of hormones:

• Insulin — secreted by the pancreas (islets of Langerhans); regulates blood glucose levels by promoting glucose uptake into cells.
• Adrenaline (epinephrine) — secreted by the adrenal medulla; mediates the "fight-or-flight" response to stress (increases heart rate, blood pressure). …