Loading PDF...
Chapter Analysis
Intermediate13 pages • EnglishQuick Summary
Chapter 19 of the Class 11 Biology NCERT textbook focuses on the endocrine system and the hormones it secretes. It explains the role and function of different endocrine glands such as the pituitary, thyroid, adrenal, and pancreas, among others. The chapter also discusses hormone action mechanisms, highlighting the interaction of hormones with receptors at a molecular level. The chapter emphasizes the significance of hormones in maintaining physiological balance and homeostasis in the body.
Key Topics
- •Endocrine and exocrine glands
- •Human endocrine system
- •Hormone classification and mechanism of action
- •Roles of major endocrine glands
- •Regulation of glucose and calcium homeostasis
- •Impact of hormone imbalances
- •Neuroendocrine interconnections
Learning Objectives
- ✓Understand the structure and function of endocrine glands
- ✓Identify key hormones and their roles in the body
- ✓Explain the mechanism of hormone action
- ✓Describe how homeostasis is maintained through hormonal regulation
- ✓Evaluate the impact of hormone deficiencies and excesses
- ✓Analyze the interconnections between the nervous and endocrine systems
Questions in Chapter
Define the following: (a) Exocrine gland (b) Endocrine gland (c) Hormone
Page 251
Diagrammatically indicate the location of the various endocrine glands in our body.
Page 251
List the hormones secreted by the following: (a) Hypothalamus (b) Pituitary (c) Thyroid (d) Parathyroid (e) Adrenal (f) Pancreas (g) Testis (h) Ovary (i) Thymus (j) Atrium (k) Kidney (l) G-I Tract
Page 251
Fill in the blanks: Hormones Target gland (a) Hypothalamic hormones __________________ (b) Thyrotrophin (TSH) __________________ (c) Corticotrophin (ACTH) __________________ (d) Gonadotrophins (LH, FSH) __________________ (e) Melanotrophin (MSH) __________________
Page 251
Write short notes on the functions of the following hormones: (a) Parathyroid hormone (PTH) (b) Thyroid hormones (c) Thymosins (d) Androgens (e) Estrogens (f) Insulin and Glucagon
Page 251
Give example(s) of: (a) Hyperglycemic hormone and hypoglycemic hormone (b) Hypercalcemic hormone (c) Gonadotrophic hormones (d) Progestational hormone (e) Blood pressure lowering hormone (f) Androgens and estrogens
Page 251
Which hormonal deficiency is responsible for the following: (a) Diabetes mellitus (b) Goitre (c) Cretinism
Page 251
Briefly mention the mechanism of action of FSH.
Page 251
Match the following: Column I Column II (a) T4 (i) Hypothalamus (b) PTH (ii) Thyroid (c) GnRH (iii) Pituitary (d) LH (iv) Parathyroid
Page 251
Additional Practice Questions
Explain the difference between exocrine and endocrine glands.
easyAnswer: Exocrine glands have ducts and release their secretions onto an epithelial surface, while endocrine glands lack ducts and release hormones directly into the bloodstream.
Discuss how insulin and glucagon regulate blood glucose levels.
mediumAnswer: Insulin decreases blood glucose levels by facilitating cellular uptake of glucose and glycogen synthesis, while glucagon increases blood glucose by stimulating glycogenolysis and gluconeogenesis.
Describe the role of the adrenal medulla in the 'fight or flight' response.
mediumAnswer: The adrenal medulla secretes adrenaline and noradrenaline, which increase heart rate, blood pressure, and energy availability, preparing the body to respond to stress.
What are the consequences of low thyroid hormone production?
hardAnswer: Low thyroid hormone production can lead to hypothyroidism, characterized by fatigue, weight gain, cold intolerance, and, in children, developmental delays.
Explain the mechanism of hormone action involving membrane-bound receptors.
hardAnswer: Hormones bind to specific membrane receptors, activating second messengers within the cell that lead to a physiological response.
Why is the hypothalamus considered a neuroendocrine organ?
mediumAnswer: The hypothalamus is considered a neuroendocrine organ because it produces hormones that regulate various endocrine functions, acting as a bridge between the nervous and endocrine systems.
What are the primary functions of glucocorticoids?
mediumAnswer: Glucocorticoids primarily regulate metabolism by promoting gluconeogenesis, lipolysis, and proteolysis. They also have anti-inflammatory and immunosuppressive effects.
List some hormones produced by the gastrointestinal tract and their functions.
mediumAnswer: The GI tract produces hormones like gastrin, secretin, and cholecystokinin, which regulate digestive processes such as enzyme secretion and gut motility.
How do gonadotropins regulate reproductive functions?
mediumAnswer: Gonadotropins like LH and FSH stimulate the gonads to produce sex hormones and gametes, thereby regulating reproductive processes.