NCERT Solutions for Class 11 Biology Chapter 22

Chapter 22 of NCERT Class 11 Biology textbook explains the endocrine glands that are present in the body. To help students revise what they have learned in the chapter, the textbook has a set of questions related to the topic. This is where NCERT Solutions for Class 11 Biology Chapter 22 can be of great help to students.

The Class 11 Biology NCERT Solutions Chapter 22 by Extramarks have answers to all the textbook questions. These are prepared by subject matter experts while ensuring that every answer meets the guidelines given by CBSE. 

NCERT Solutions for Class 11 Biology Chapter 22 – Chemical Coordination and integration

Access NCERT Solutions for Class 11 Biology Chapter 22 – Chemical Coordination and Integration

NCERT Solutions For Class 11 Biology Chapter 22 

For scoring well, students need to have complete knowledge of concepts explained in every chapter. Apart from this, they must know the right answers to the questions asked in the NCERT Biology textbook. This is the reason that referring to NCERT Solutions for Class 11 Biology Chapter 22 plays an important role in exam preparation. With answers explained with examples and diagrams, NCERT Solutions can make learning easy and more interesting for students. 

NCERT Solutions of Class 11 Biology Chapter 22 

Class 11 Biology NCERT Chapter 22 explains endocrine glands in our body. Diagrammatic representation of these glands aids students in getting clarity about the location of these glands in the body. This chapter also talks about the hormonal deficiencies in the various parts of the human body along with the mechanism of action of FSH overview given in an in-depth manner. 

By referring to Class 11 Biology NCERT Chapter 22 Solutions, students can ace their preparation for the school and competitive exams. Additionally, they will learn the right way to answer a question to avoid any kind of marks deduction during evaluation.

Benefits of Chapter 22 Biology Class 11 NCERT Solutions 

Achieving success in examinations is possible with Class 11 Biology NCERT Solutions Chapter 22. Here is how these solutions are beneficial:

  • Every answer explains the concept in an in-depth manner. Examples and diagrams are also used, wherever required so that students do not have any doubt related to the answer.
  • The solutions are prepared by subject matter experts at Extramarks
  • The solutions follow the latest CBSE guidelines.

Related Questions 

Release of pancreatic juice is stimulated by:

  1. A) Enterokinase
  2. B) Secretin
  3. C) Trypsinogen
  4. D) Cholecystokinin

Answer: D) Cholecystokinin

Explanation: The gastrointestinal system has a peptide hormone called Cholecystokinin. This hormone aids in simulating the digestion of protein and fat. It is secreted by the small intestine. This hormone stimulates the secretion of pancreatic juice from the pancreas and plays a part in inciting bile secretion from the gallbladder and pancreas.  

The person with Turner’s syndrome has

  1. A) 45 autosomes and X sex chromosomes
  2. B) 44 autosomes and XYY sex chromosomes
  3. C) 45 autosomes and XYY sex chromosomes
  4. D) 44 autosomes and X sex chromosomes

Answer: D) 44 autosomes and X sex chromosomes

Explanation: Turner Syndrome is caused by the aneuploidy of the X chromosome (complete or partial absence of X Chromosome). A person with Turner Syndrome has a genotype of 44+XO. Only females have this syndrome. They suffer from ovarian insufficiency, limited secondary sexual characters, webbed skin over the neck, short statures, etc. Females with this syndrome have underdeveloped sex organs and are sterile. 

A hormone, secreted by the endocrine cells of duodenal mucosa which influences the release of pancreatic juice is

  1. A) Relaxin
  2. B) Cholecystokinin
  3. C) Secretin
  4. D) Progesterone

Answer: B) Cholecystokinin

Explanation: The mucosa of the small intestine secretes a hormone known as Cholecystokinin Pancreozymin. It stimulates the pancreas to release pancreatic juice and the gallbladder to release bile. 

Osmoreceptors are present in-

  1. A) Hypothalamus
  2. B) Hypophysis
  3. C) Epiphysis
  4. D) Epithalamus

Answer: A) Hypothalamus

Explanation: Osmoreceptors in the anterior hypothalamus’ supraoptic and paraventricular areas are responsible for the detection of changes in the osmolarity of blood plasma. They also aid in the secretion of ADH for the purpose of maintaining balance. 

Gastric secretion is stopped by hormone

  1. A) Enterogastrone
  2. B) Gastrin
  3. C) Pancreozymin
  4. D) Cholecystokinin

Answer: A) Enterogastrone

Explanation: The duodenal mucosa secrets the Enterogastrone hormone. This hormone inhibits gastric secretion. 

A condition in which the body’s internal environment remains relatively constant within limits is

  1. A) Hematoma
  2. B) Haemopoiesis
  3. C) Homeostasis
  4. D) Hemostasis

Answer: C) Homeostasis

Explanation: The maintenance of a state of steady internal conditions (chemical and physical) by living things is known as Homeostasis. This state of internal stability is essential for a living organism to function optimally. Homeostasis includes multiple variables like the fluid balance and body temperature being maintained at certain limits that are preset. The internal body temperature of a human being is the best example. 

How does chemical coordination take place in plants?

Chemical coordination occurs in plants through plant hormones. For instance, for growth, the hormone Auxin is responsible while in the fast-growing parts of a plant, cell division is aided by cytokinin. 

Q.1 Define the following:
(a) Exocrine gland
(b) Endocrine gland
(c) Hormone

Ans-

(a) Exocrine gland: The glands which secrete their products via a duct are called exocrine glands. Examples: sweat glands, salivary glands, mammary glands and liver.

(b) Endocrine gland: The glands that do not secrete their products (hormones) via any duct, but directly secrete them into the bloodstream or into its surrounding tissues are known as endocrine glands. Examples: adrenal gland, pituitary gland and thyroid glands.

(c) Hormone: The secretions of endocrine glands that perform their function at a distant location, away from the location of their origin by travelling through the bloodstream are called hormones. They can also diffuse to their neighbouring tissues.

Current scientific definition defines hormones as “Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts.” Example: thyroid hormone, follicle stimulating hormone, testosterone.

Q.2 Diagrammatically indicate the location of the various endocrine glands in our body.

Diagrammatic representation of the location of various endocrine glands in our body:

Q.3 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

Ans-

(a) Hypothalamus: Two types of hormones are secreted by hypothalamus:

(i) Releasing hormones: Gonadotropin releasing hormone, thyrotrophin releasing hormone, somatotrophin releasing hormone and adrenocorticotrophic hormone

(ii) Inhibiting hormones: Somatostatin, growth- inhibiting hormone and melanocyte-stimulating hormone

(b) Pituitary: List of hormones secreted by two different parts of the pituitary gland:

(i) Hormones secreted by Adenohypophysis: Growth hormone (GH), prolactin, thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), luteinizing hormone (LH), melanocyte stimulating hormone (MSH) and follicle stimulating hormone (FSH)

(ii) Hormones secreted by Neurohypophysis: Oxytocin and vasopressin

(c) Thyroid: Thyroxin (T4), triiodothyronine (T3) and thyrocalcitonin

(d) Parathyroid: Parathyroid hormone (PTH)

(e) Adrenal: List of hormones secreted by adrenal gland:

  • Corticoid hormones are secreted by adrenal cortex. Corticoids are further divided into

-glucocorticoid (hormone secreted is cortisol)

-mineralocorticoid (hormone secreted is aldosterone).

  • Catecholamines are secreted by adrenal medulla. It secretes adrenaline (also called epinephrine) and noradrenaline (also called norepinephrine).

(f) Pancreas: Insulin and glucagon

(g) Testis: Testosterone

(h) Ovary: Estrogen and progesterone

(i) Thymus: Thymosins

(j) Atrium: Atrial natriuretic hormone (ANH)

(k) Kidney: Erythropoietin

(l) G-I Tract: Gastrin, secretin, cholecystokinin and gastric inhibitory peptide (GIP, also known as glucose-dependent insulinotropic peptide).

Q.4 Fill in the blanks:

Q.5 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

Ans-

(a) Parathyroid hormone (PTH): Parathyroid hormone is a peptide hormone and secreted by parathyroid glands. It plays a significant role in:

  • Calcium homeostasis in the body. It increases the calcium level in blood. It also stimulates calcium absorption from digested food and reabsorption of Ca++ by renal tubules.
  • It stimulates the dissolution and demineralisation of bones.

(b) Thyroid hormones: Thyroxine (T4), tri-iodothyronine (T3) and thyrocalcitonin are collectively called as thyroid hormones. Iodine is essential for an adequate rate of thyroid hormone synthesis. Low level of thyroid hormones (hypothyroidism) results in enlargement of the thyroid gland, commonly called goitre. Excessive synthesis of thyroid hormones is called hyperthyroidism which is also harmful to the body. Thyroid hormones are essential for many physiological processes.

  • They play an important role in maintaining normal basal metabolic rate (BMR).
  • They control the metabolism of carbohydrates, proteins and fats.
  • They also help in red blood cell (RBCs) formation and regulating blood calcium levels.
  • They also influence water and electrolytes balance.

(c) Thymosins: It is a peptide hormone and secreted by the thymus. Its functions are:

  • Differentiation of T-lymphocytes which are essential for cell-mediated immunity.
  • Promotes antibody production which provides humoral immunity.

(d) Androgens: Androgens are a group of hormones. Main androgen hormone is testosterone hormone. Androgens are secreted by leydig cells of testes. The main functions of androgens are:

  • It stimulates the development of male secondary sex characteristics.
  • It is required for the development, maturation and functions of the male accessory sex organs like epididymis, vas deferens, seminal vesicles, prostate gland, urethra, etc.
  • It stimulates spermatogenesis (formation of spermatozoa) and influence male sexual behaviour (libido).

(e) Estrogens: Estrogen is a steroid hormone produced by the ovaries. The main functions of estrogen are:

  • It stimulates the development of female secondary sex organs.
  • It helps in the development of ovarian follicles and mammary glands.
  • It also regulates female sexual behaviour.

(f) Insulin and Glucagon: Functions of Insulin and glucagon:

  • Insulin stimulates uptake of excess glucose and its utilisation by liver cells by the process of glycogenesis. In glycogenesis, excess glucose is converted into its polymer glycogen and stored in the liver cells. Deficiency of insulin results in a disease, called diabetes mellitus.
  • Glucagon acts in just the opposite manner. In case of low glucose level in blood, it stimulates the breakdown of glycogen and release of glucose in the bloodstream. It also stimulates the synthesis of glucose from non-carbohydrate substrates like pyruvate, lactate, glycerol, etc., by the process of gluconeogenesis.

Q.6 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

Ans-

(a) Hyperglycemic hormone and hypoglycemic hormone: Hyperglycemic hormone- Glucagon, Hypoglycemic hormone- Insulin

(b) Hypercalcemic hormone: Parathyroid hormone

(c) Gonadotrophic hormones: Luteinising hormone, follicle-stimulating hormone

(d) Progestational hormone: Progesterone

(e) Blood pressure lowering hormone: Atrial natriuretic factor (ANF)

(f) Androgens and estrogens: Androgen- Testosterone, Estrogen- Estradiol

Q.7 Which hormonal deficiency is responsible for the following?
(a) Diabetes mellitus
(b) Goitre
(c) Cretinism

Ans-

(a) Diabetes mellitus: Diabetes mellitus is caused by deficiency of insulin. It is also caused when insulin becomes non-responsive to blood glucose level.

(b) Goitre:Goitre is the enlargement of thyroid glands and happens due to the deficiency of thyroid hormones.

(c) Cretinism: It is caused by low level of thyroid during pregnancy that results in the stunted growth of baby.

Q.8 Briefly mention the mechanism of action of FSH.

Ans-

Follicle Stimulating Hormone (FSH) is synthesised and secreted by the anterior lobe of the pituitary gland. FSH, being a glycoprotein, is insoluble in lipid thus, cannot enter the target cells. So, these glycoproteins first bind with the specific receptor molecules, that are found on the surface of a cell membrane, form a hormone-receptor complex and activate the cellular system to perform functions.

Mechanism of Action: After the release of FSH from the site of production, it reaches the ovary, uterus or testis and binds to FSH receptor, present at the plasma membrane of these organs. FHS receptor is a transmembrane G-protein coupled receptor protein. The binding of FSH to receptor generates second messengers (cAMP). Secondary messengers start several biochemical changes inside these organs and carry out many important functions.

Functions:

  • In the ovary, it results in follicular development.
  • In the uterus, it is involved in the development of secretory endometrium during the luteal phase.
  • In the males, the FSH is responsible for spermatogenesis.

Q.9 Match the following:

Column I Column II
(a) T4 (i) Hypothalamus
(b) PTH (ii) Thyroid
(c) GnRH (iii) Pituitary
(d) LH (iv) Parathyroid

Ans-

Column I Column II
(a) T4 (ii) Thyroid
(b) PTH (iv) Parathyroid
(c) GnRH (i) Hypothalamus
(d) LH (iii) Pituitary

 

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FAQs (Frequently Asked Questions)

1. What are endocrine glands?

The release of hormones into the bloodstream is carried out by the endocrine glands. Hormones can travel through the cells into the other parts of the body due to being released into the bloodstream. A person’s growth and development, mood, metabolism, reproduction, and functioning of their organs are controlled by the endocrine glands. This gland is responsible for regulating and controlling the number of hormones released in the body. Pituitary Gland, Hypothalamus, Parathyroid, Thyroid, and Pineal Gland are some of the endocrine glands among a few others. An endocrine gland is responsible for multiple functions and is a crucial part of the body.

Note down some properties of hormones.

The following are some properties of hormones:

  • Hormones do not have antigens present in them. 
  • Endocrine glands release hormones into the bloodstream. 
  • They aid in homeostasis maintenance.
  • They have a short life span.
  • These hormones are needed by the body in low concentrations. 
  • Metabolic and physical activities are influenced by them. 
  • Some hormones react quickly.
  • It has been observed that certain hormones are carried to specific organs. 
  • Prohormones like proinsulin are released in an inactive form.

2. What topics are included in Chapter 22 of Class 11 Biology?

Biology Class 11 Chapter 22 – Chemical Coordination and Integration includes the following topics:

 

  • Introduction
  • Endocrine Glands And Hormones
  • Endocrine System
  • The Hypothalamus
  • The Pituitary Gland
  • The Pineal Gland
  • Thyroid Gland
  • The Parathyroid Gland
  • Thymus
  • Adrenal Gland
  • Pancreas
  • Testis
  • Ovary
  • Hormones of Heart, Kidney and Gastrointestinal Gland
  • Mechanism of Hormone Action
  • Summary

3. What is the difference Between Endocrine Glands and Exocrine Glands?

Endocrine Glands Exocrine Glands
The secretion of hormones into the bloodstream of the body is executed by endocrine glands.  Secretion by this gland is released either external to or into the surface of an organ. This is done with the help of a duct. 
Endocrine glands are ductless glands. These glands have ducts.
They release hormones.  They release enzymes, mucus, sebum, and sweat.
Examples of endocrine glands are parathyroid glands, adrenal glands, thyroid glands, etc. Examples of exocrine glands are the pancreas, liver, salivary glands, etc.

4. What is a Pineal Gland?

The Pineal Gland is situated on the dorsal side of the brain. This gland secretes a hormone known as Melatonin which plays a very important role in the human body. It aids in the regulation of the body’s 24-hour or diurnal rhythm. For instance, it maintains the cycle of sleep and wake, body temperature, etc. Melatonin also impacts the menstrual cycle, defence capability, metabolism, and pigmentation.

5. What is the classification of hormones? Also, name some endocrine glands and hormones secreted by them.

The hormones are classified into:

Lipid soluble hormones: These types of hormones include thyroid and steroid hormones.

Water-soluble hormones: These types of hormones include amine, peptide and protein hormones.

Some of the endocrine glands that secrete hormones are listed below:

  • Thyroid Gland – Thyroxine
  • Anterior Pituitary – Adrenocorticotropic hormone
  • Pineal Gland – Melatonin
  • Posterior Pituitary –Oxytocin
  • Testes – Testosterone
  • Adrenal Gland – Cortisol and Adrenaline
  • Ovaries – Progesterone and Estrogen

6. Give a brief introduction about the Thymus gland.

The Thymus gland is lobular structured and is located behind the sternum in between the lungs on the ventral side of the aorta. The development of the immune system of the body is aided by this gland. This gland releases the peptide hormones known as thymosins, which play a crucial role in the maturation of T cells. This hormone is active till puberty. After puberty, it shrinks and gets replaced by fat. Antibodies are produced by this hormone as well. Degeneration of the thymus gland occurs in old individuals which leads to a reduction in the production of thymosins.