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Chemical Coordination and Integration

NCERT Class 11 Biology Chapter 19

Chemical Coordination and Integration for Class 11 Biology and NEET: endocrine glands and hormones, their disorders and the mechanism of hormone action.

4 topics Updated 8 Nov 2026

For: Class 11 and NEET

In the syllabus: NEET Class 11 syllabus

With your textbook

NCERT Biology (Class 11), Chapter 19 “Chemical Coordination and Integration”, reprint 2026-27.

Open the official NCERT chapter (PDF, 2.1 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Endocrine glands and hormones

    Why endocrine glands are ductless, exocrine vs endocrine glands, and NCERT’s two hormone definitions.

    NCERT Section 19.1 8 min read 3 solved examples 6 practice questions

  2. Human endocrine system: glands and hormones

    Endocrine glands and their hormones, from hypothalamus to gonads, their disorders and a labelled diagram.

    NCERT Section 19.2 22 min read 8 solved examples 7 practice questions

  3. Hormones of heart, kidney and gastrointestinal tract

    Gastrin, secretin, CCK and GIP and their targets, plus the heart’s ANF and the kidney’s erythropoietin.

    NCERT Section 19.3 8 min read 4 solved examples 6 practice questions

  4. Mechanism of hormone action

    Membrane and intracellular receptors, peptide vs steroid hormones, second messengers, with a diagram.

    NCERT Section 19.4 9 min read 3 solved examples 7 practice questions

Key formulas in this chapter

Endocrine glands and hormones

  • endocrine gland: no duct (ductless) → hormone into the blood
  • exocrine gland: duct → secretion to a surface
  • hormone: non-nutrient, intercellular messenger, trace amounts
  • neural: fast, short-lived; hormonal: continuous regulation

Human endocrine system

  • anterior pituitary: GH, PRL, TSH, ACTH, LH, FSH; intermediate: MSH; posterior stores oxytocin, ADH
  • GH: excess → gigantism (child), acromegaly (adult); low secretion → pituitary dwarfism
  • calcium: PTH raises, TCT lowers
  • glucose: glucagon raises (α-cells), insulin lowers (β-cells)
  • adrenal: medulla → adrenaline, noradrenaline; cortex → cortisol, aldosterone

Hormones of heart, kidney and gut

  • heart (atrial wall) → ANF → vessels dilate → blood pressure falls
  • kidney → erythropoietin → erythropoiesis (RBC formation)
  • gastrin → gastric glands: HCl, pepsinogen
  • secretin → exocrine pancreas: water, bicarbonate
  • CCK → pancreas (enzymes) + gall bladder (bile); GIP → inhibits gastric secretion, motility

Mechanism of hormone action

  • protein hormone → membrane receptor → intracellular signalling → response
  • steroid, iodothyronine → intracellular receptor → genome → mRNA → proteins
  • groups: peptide/protein; steroid; iodothyronine; amino-acid derivative

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