# Chemical Coordination and Integration Notes | SwaVid Chemical Coordination and Integration, NCERT Class 11 Biology: notes with key ideas, key terms, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-11/biology/chapter/chemical-coordination-and-integration Source: https://www.swavid.com/cbse/class-11/biology/chapter/chemical-coordination-and-integration # Chemical Coordination and Integration ## Key terms ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 11 Biology on SwaVid ### Endocrine glands and hormones ### Hypothalamus and pituitary gland ### Thyroid and parathyroid glands ### Adrenal and pineal glands ### Pancreas and gonads ### Hormones of non-endocrine tissues ### Mechanism of hormone action ### Related chapter ### Related chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 11 › Biology › Chemical Coordination and Integration Notes written by SwaVid from the NCERT textbook. Class 11 Biology, Chapter 19. Key ideas, formulas and common mistakes. CBSE prints 18 marks for Unit V, not for this chapter alone. Short answer. This chapter describes the endocrine system, endocrine glands, and the chemical messengers called hormones in the human body. It explains how these hormones regulate physiological processes, maintain homeostasis, and act through specific cell surface or intracellular receptors. Source: NCERT Biology (Reprint 2026-27) , Chapter 19, Chemical Coordination and Integration Endocrine glands lack ducts and release their secretions directly into the bloodstream. Hormones are non-nutrient chemicals that act as intercellular messengers and are produced in trace amounts. The hypothalamus contains neurosecretory cells that secrete releasing and inhibiting hormones to control the pituitary gland. The pituitary consists of the adenohypophysis, which secretes hormones like GH, PRL, TSH, ACTH, LH, and FSH, and the neurohypophysis, which stores and releases oxytocin and vasopressin produced by the hypothalamus. The thyroid gland secretes thyroxine (T4), triiodothyronine (T3), and thyrocalcitonin (TCT), regulating basal metabolic rate and blood calcium levels. Four parathyroid glands secrete parathyroid hormone (PTH), a hypercalcaemic hormone that increases calcium levels in the blood. The pineal gland secretes melatonin, which regulates the 24-hour diurnal rhythm of the body. The adrenal gland consists of an outer cortex producing corticoids and an inner medulla producing adrenaline and noradrenaline for emergency responses. The pancreas is a composite gland whose islets of Langerhans secrete glucagon from alpha cells and insulin from beta cells to maintain blood glucose homeostasis. Testes produce androgens like testosterone, while ovaries produce estrogen and progesterone. Tissues like the heart wall secrete atrial natriuretic factor (ANF), the kidneys produce erythropoietin, and the gastrointestinal tract secretes gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide (GIP). Hormones bind to specific hormone receptors on target tissues. Water-soluble peptide hormones bind to membrane-bound receptors and generate secondary messengers like cyclic AMP, whereas lipid-soluble steroid and thyroid hormones enter cells to interact with intracellular receptors and regulate gene expression. Try each question first. Then tap it to see the answer. Low blood Ca²⁺ levels stimulate the parathyroid glands to secrete parathyroid hormone (PTH). PTH acts on bones by stimulating the process of bone resorption (demineralisation), which releases Ca²⁺ into the blood. Parathyroid hormone (PTH); it stimulates bone resorption. Alpha cells secrete glucagon and beta cells secrete insulin. Insulin enhances cellular glucose uptake and utilization in hepatocytes, stimulating the conversion of glucose to glycogen (glycogenesis). Alpha cells secrete glucagon, beta cells secrete insulin; insulin promotes glycogenesis in hepatocytes. Estrogen is a lipid-soluble steroid hormone, allowing it to diffuse freely across the lipid bilayer to bind intracellular receptors. FSH is a water-soluble peptide/protein hormone that cannot cross the lipid membrane and must bind to membrane-bound receptors. Estrogen is lipid-soluble (steroid), whereas FSH is water-soluble (peptide/protein). Neural Control and Coordination . Body Fluids and Circulation . Excretory Products and their Elimination . The 19 chapters of Class 11 Biology . CBSE does not give marks to one chapter. It prints 18 marks for Unit V, Human Physiology, which includes Chemical Coordination and Integration. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. This is the last chapter in the NCERT books for Class 11 Biology. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Ch 19 NCERT book - 18 marks, Unit V - 3 quick checks - Confusing the site of production of oxytocin and vasopressin with their site of release . Remember that oxytocin and vasopressin are synthesized by the hypothalamus and only stored and released by the posterior pituitary (neurohypophysis). - Mixing up the target hormones and effects of PTH versus TCT on blood calcium . PTH is hypercalcaemic and mobilizes Ca²⁺ from bones into blood, whereas TCT is hypocalcaemic and lowers blood Ca²⁺ levels. - Assuming steroid hormones generate second messengers like cyclic AMP or IP3 . Water-soluble peptide hormones use membrane-bound receptors and second messengers, while lipid-soluble steroid and iodothyronine hormones cross the membrane to bind intracellular receptors directly. - Confusing diabetes mellitus with diabetes insipidus . Diabetes mellitus involves insulin deficiency and high blood glucose, whereas diabetes insipidus involves vasopressin (ADH) deficiency and excessive water loss without sugar in the urine. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 11](https://www.swavid.com/cbse/class-11) - [Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup) - [All 19 chapters](https://www.swavid.com/cbse/class-11/biology/chapters) - [NCERT Biology (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/neural-control-and-coordination) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/body-fluids-and-circulation) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/excretory-products-and-their-elimination) - [Class 11 Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup)