Question
List the major hormones secreted by the pituitary gland, thyroid gland, and adrenal glands. State the function of each hormone.
(NCERT Class 8, Chapter 10 — Reaching the Age of Adolescence)
Solution — Step by Step
Located at the base of the brain, the pituitary controls other endocrine glands. Key hormones:
| Hormone | Function |
|---|---|
| Growth Hormone (GH) | Controls growth of bones and muscles. Excess causes gigantism; deficiency causes dwarfism |
| Thyroid Stimulating Hormone (TSH) | Tells the thyroid gland to produce its hormones |
| Follicle Stimulating Hormone (FSH) | Controls development of eggs (females) and sperm (males) |
It’s called the “master gland” because it controls the activity of other glands like the thyroid and adrenals.
Located in the neck, butterfly-shaped. Main hormone:
| Hormone | Function |
|---|---|
| Thyroxine () | Controls metabolic rate (how fast body cells convert food to energy). Needs iodine for its production |
Deficiency of iodine leads to goitre (swelling of the thyroid gland in the neck). Deficiency in children causes cretinism (stunted growth and mental development). That’s why iodised salt is so important.
Located on top of each kidney (ad = near, renal = kidney). Key hormone:
| Hormone | Function |
|---|---|
| Adrenaline (Epinephrine) | The “fight or flight” hormone. Released during stress, fear, or anger. Increases heart rate, blood pressure, and blood sugar — prepares the body for emergency action |
When you feel your heart pounding before an exam or while watching a scary movie — that’s adrenaline at work.
Why This Works
Endocrine glands are ductless — they release hormones directly into the blood. These hormones travel through the bloodstream to target organs, where they trigger specific responses. Think of hormones as chemical messengers: small in quantity but powerful in effect.
The pituitary-thyroid-adrenal trio covers the most commonly asked hormones at the Class 8 level. The pituitary sits at the top of the hierarchy (master gland), controlling when other glands should secrete their hormones. The thyroid handles everyday metabolism, while the adrenals handle emergency situations.
Alternative Method — Quick memory table
Remember PTA (like Parent-Teacher Association):
- Pituitary → Growth hormone (think: Physical growth)
- Thyroid → Thyroxine (think: Thyroxine needs iodine)
- Adrenal → Adrenaline (think: Action mode, fight or flight)
Common Mistake
Students often confuse “endocrine” glands (ductless, secrete into blood) with “exocrine” glands (have ducts, secrete onto surfaces — like sweat glands or salivary glands). In exams, if the question asks about the endocrine system, mentioning sweat glands or salivary glands will cost you marks. Only ductless glands that secrete hormones into the bloodstream qualify as endocrine.