Class 11 Biology Chapter 19 Chemical Coordination and Integration – Revision Notes

Quick revision notes for Class 11 Biology Chapter 19 (Chemical Coordination and Integration). These Class 11 Biology Chapter 19 notes are ideal for quick revision just before exams.

Major Glands

• Pituitary (master gland), Thyroid (thyroxine, metabolic rate), Parathyroid (Ca²⁺), Adrenal (cortisol/adrenaline), Pancreas (insulin/glucagon), Gonads.

Hormone Action

• Peptide hormones: surface receptors, second messengers.
• Steroid hormones: lipophilic, intracellular/nuclear receptors, direct gene expression.

Regulation

• Negative feedback maintains hormone homeostasis (e.g. thyroxine → suppresses TSH).

Disorders

• Diabetes mellitus, goitre (iodine deficiency), dwarfism/gigantism (GH imbalance).

One-Line Summary

The endocrine system uses hormones secreted by glands like the pituitary, thyroid, adrenal, and pancreas to regulate body functions through peptide (surface-receptor) or steroid (gene-regulating) mechanisms, maintained by negative feedback.

Written by Satish

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