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

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

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration.

VERY SHORT ANSWER QUESTIONS

Question 1.
Which of the two adrenocortial layers, zona glomerulosa and zona reticularis lies outside enveloping the other?
Solution:
Zona glomerulosa envelops zona reticularis from the outside.

Question 2.
What is erythropoiesis? Which hormone stimulates it?
Solution:
The process of formation of RBC is Erythropoiesis. Erythropoietin, a Peptide hormone secreted from the juxtaglomerular cells of kidney stimulates erythropoiesis.

Question 3.
Name the only hormone secreted by pars intermedia of the pituitary gland.
Solution:
The only hormone secreted by Pars intermedia ^ of pituitary gland is Melanocyte Stimulating hormone (MSH). This hormone causes dispersal of pigment granules in the pigment cells, which darken the colour in certain animals like fishes and amphibians.

Question 4.
Name the endocrine gland that produces calcitonin and mention the role played by this ‘ hormone.
Solution:
Calcitonin/thyrocalcitonin linear polypeptide hormone comprising of 32 amino acids that is produced in humans primarily by the parafollicular cells of the thyroid gland. It checks excess Ca2+ and phosphate in plasma by • decreasing mobilization from bones.

Question 5.
Name the hormone that helps in cell-mediated immunity.
Solution:
The hormone thymosin plays a maj or role in the development and differentiation of T-lymphocytes, which provide cell-mediated immunity.

Question 6.
A patient complains of constant thirst, excessive 3. passing of urine and low blood pressure. When the doctor checked the patients’ blood glucose and blood insulin level, the level were normal or 4. slightly low. The doctor diagnosed the condition a diabetes insipid us. But he decided to measure one more hormone in patients blood. Which hormones does the doctor intend to measure?
Solution:
The doctor intends to measure the hyperglycaemia hormone, and its action is opposite to that of insulin Excess of glucose in blood suppresses the secretion of glucose, whereas fall in glucose level enhance glucose production.

Question 7.
Correct the following statements by replacing the term underlined.
(a) Insulin is a steroid hormone.
(b) TSH is secreted from the corpus leteum.
(c) Tetraiodothyronine is an emergency hormone.
(d) the pineal gland is located on the anterior part of the kidney.
Solution:
(a) Insulin is a peptide hormone
(b) TSH is secreted from the pars distalis region ofpitutary.
(c) Adrenaline is an emergency hormone.
(d) The adrenal gland is located on the anterior part of the kidney.

Question 8.
Match the following columns.
Column I                           Column II
A. Oxytocin                     1. Amino acid derivative
B. Epinephrine                2. Steroid
C. Progesterone             3. Protein
D. Growth hormone       4. Peptide
Solution:
The correct matching is
Column I                             Column II
A. Oxytocin                 –       Peptide
B. Epinephrine            –       Amino acid derivative
C. Progesterone         –        Steroid
D. Growth hormone   –       Protein

SHORT ANSWER QUESTIONS

Question 1.
What is the role-played by luteinising hormones in males and females respectively.
Solution:

  1. LH and FSH stimulate activity of gonads and hence are called gonadotropins.
  2. Luteinising hormone (LH) in males stimulates the synthesis and secretion of hormones called androgens from testis. Androgens along with FSH (Follicle Stimulating Hormone) regulate spermatogenesis.
  3. LH induces ovulation of fully mature follicles in females and maintains the corpus luteum, formed from the remnants of the graafian follicles after ovulation. This secretes progesterone.

Question 2.
George comes on a vacation to India from US. The long journey disturbs his biological system and he suffers from jet lag. What is the cause of his discomfort?
Solution:

  1. The melatonin hormone secreted by the pineal gland is also called as ‘sleep hormone’ as it promotes sleep-wake cycle.
  2. The disruption of the body clock as it is out of synchronisation because of the unfamiliar time zone of the destination causes Jet lag. The body experiences different patterns of light and dark conditions than it is normally used to, this disrupts the natural sleep-wake cycle.
  3. A hormone that plays a key role in body rhythms and causes jet lag is melatonin. Eyes perceive darkness after the sun sets and alert the hypothalamus to begin releasing melatonin, which promotes sleep. Conversely, when the eyes perceive sunlight, they induce the hypothalamus to with hold melatonin prodtiction.
  4. The hypothalamus however cannot readjust its schedule instantly and it may take several days, to overcome this problem.

Question 3.
Inflammatory responses can be controlled by a certain steroid. Name the steroid, its source and also its other important functions.
Solution:

  1. Glucocorticoids cortisol in particular, produce anti-inflammatory reactions and suppress the immune response.
  2. The middle zone, in adrenal cortex which is the widest of three zones called zona fasciculata is the source for glucocorticoids.
  3. The glucocorticoids as the name suggests affect carbohydrate metabolism and metabolism of proteins and fats.
  4. They stimulate gluconeogenesis, lipolysis and proteolysis. They also inhibit utilization of amino acid and cellular uptake. Cortisol is also called stress hormone as it copes with stress.

Question 4.
Old people have weak immune system. What could be the reasons?
Solution:

  1. A major role in the development of the immune system is played by thymus.
  2. The thymus gland is a lobular structure located on the dorsal side of the heart and the aorta. It is derived from the endoderm of the embryo. Thymus secretes a hormone named thymosin which stimulates the development of white blood cells (WBCs), involved in producing immunity.
  3. In old individuals, thymus is degenerated which results in decreased production of thymosin. The immune system as a result becomes weak, in old people.

LONG ANSWER QUESTIONS

Question 1.
Calcium plays a very important role in the formation of bones. Write on the role of endocrine glands and hormones responsible for maintaining calcium homeostasis.
Solution:
The hormones and endocrine glands that are responsible for maintaining calcium
homeostasis, are thyroid and parathyroid glands j and their associated hormones are calcitonin and Parathyroid Hormone (PTH).
(i) Parathyroid glands – These glands developed from the endoderm of the embryo. The cells of parathyroid glands are
of two types – chief cells and oxyphil cells. The chief cells of the parathyroid glands secrete parathyroid hormone (PTH).
This hormone (PTH) is involved in regulation of calcium and phosphate balance between the blood and other tissue. It mobilises the release of calcium into the blood from bones. PTH increases reabsorption of calcium by the body organs like intestine and kidneys.
(ii) Thyroid gland – It is the largest endocrine gland located anterior to the thyroid cartilage of the larynx in the neck.

This gland plays a major role in maintaining calcium homeostasis. It releases thyrocalcitonin hormone produced by the parafollicular cells, also called, ‘C’ cells. This hormone is secreted when the calcium level in blood gets high.

It is a 32 amino acid peptide hormone that lowers the calcium level by suppressing release of calcium ions from the bones. Calcitonin thus has an action opposite to that of the parathyroid hormone in calcium homeostasis.
NCERT Exemplar Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration 1

Question 2.
Hypothalamus is a supper master endocrine gland. Elaborate.
Solution:
Hypothalamus is a minor but extremely important part of the diencephalon that is involved in the mediation of endocrine, autonomic and behavioural fiinction.

It consists of several groups of neuro secretory cells called nuclei which produce hormones. Hypothalamus provides anatomical connection between the nervous and endocrine system. It controls the release of major hormones by

hypophysis which include :
(i) Growth Hormone Releasing Hormone stimulates the anterior lobe of the pituitary gland to release growth hormone or somatostatin.
(ii) MSH Releasing Hormone stimulates the intermediate lobe of the pituitary gland to secrete Melanocyte Stimulating Hormone (MSH)
The hormones released from hypothalamus are involved in the processes like temperature regulation, control of water balance in body, sexual behaviour and reproduction, control of daily cycles in physiological state, behaviour and mediation’ of emotional response hypothalamus is thus called as super master endocrine gland of body.
(iii) Prolactin Releasing Hormone (PRH) stimulates the anterior lobe of the pituitary gland to secret prolactin.
(iv) Gonadotropin Releasing Hormone stimulates the anterior lobe of the pituitary gland to release gonadotropic hormones (FSHandlH).
(v) Thyrotropm Releasing Hormone (TRH) stimulates the anterior lobe of pituitary gland to release Thyroid Stimulating Hormone (TSH).
(vi) Adrenocorticotrophic releasing Hormone (ARH) stimulates the anterior lobe of pituitary gland to secrete Adrenocorticotropic Hormone (ACTH). ACTH stimulates the synthesis and secretion of steroid hormones called glucocorticoids by adrenal glands.
The hormones released from hypothalamus are involved in the processes like temperature regulation, control of water balance in body, sexual behaviour and reproduction, control of daily cycles in physiological state, behaviour and mediation of emotional responses. Hypothalamus is thus called as super master endocrine gland of body.

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 22 Chemical Coordination and Integration, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 22 Chemical Coordination and Integration, drop a comment below and we will get back to you at the earliest.

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

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

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration.

Question 1.
Define the following:
(a) Exocrine glands
(b) Endocrine glands Hormones
Solution:
(a) Glands with duct is known as an exocrine gland. They secrete their secretions through ducts. Eg: Pancreas.
(b) Gland without duct is known as an endocrine gland. They directly secrete their secretions. Eg: Pituitary gland.
(c) Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts. Eg: thyroxine.

Question 2.
Diagrammatically indicate the location of the various endocrine glands in our body.
Solution:
NCERT Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration 1

Question 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-ITract
Solution:
(a) Hypothalamus: Gonadotrophic releasing hormone (GnRH), somatostatin.
(b) Pituitary: Growth hormone, prolactin, thyroid-stimulating hormone, luteinizing hormone and follicle stimulating hormone, oxytocin, vasopressin.
(c) Thyroid: triiodothyronine (T3) and tetraiodothyronine (T4).
(d) Parathyroid: Parathyroid hormone.
(e) Adrenal: Adrenaline or epinephrine and noradrenaline or norepinephrine.
(f) Pancreas: Insulin and glucagon.
(g) Testis: A group of androgens mainly testosterone.
(h) Ovary: Estrogens and progesterone.
(i) Thymus: Thymosins.
(j) Atrium: Atrial Natriuretic factor (ANF)
(k) Kidney: Erythropoietin.
(l) G-I tract: Gastrin, secretin, cholecystokinin (CCK).

Question 4.
Fill in the blanks:
Hormones                      Target gland
(a) Hypothalamic hormones ……………….
(b) Thyrotrophin (TSH) ………………
(c) Corticotrophin (ACTH) ………………
(d) GonadobTjpfains(LH,FSH) ……………….
(e) MeIanotrophin(MSH) ………………..
Solution:
(a) Anterior pituitary and posterior pituitaiy.
(b) Thyroid glands
(c) Adrenal cortex
(d) Gonads (testis and ovary)
(e) Pituitary

Question 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
Solution:
(a) The secretion of PTH is regulated by the circulating levels of calcium ions. Parathyroid hormone (PTH) increases the Ca2+ levels in the blood. PTH acts on bones and stimulates the process of bone resorption. PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from the digested food. PTH is a hypercalcemic hormone, i.e., it increases the blood Ca2+ levels. Along with TCT, it plays a significant role in calcium balance in the body.

(b) Thyroid hormones play an important role in the regulation of the basal metabolic rate. These hormones also support the process of red blood cell formation. Thyroid hormones control the metabolism of carbohydrates, proteins, and fats. Maintenance of water and electrolyte balance is also influenced by thyroid hormones. The thyroid gland also secretes the protein hormone thyrocalcitonin (TCH) which regulates blood calcium levels.

(c) Thymosins play a major role in the differentiation of T – lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote the production of antibodies to provide humoral immunity.

(d) Androgens regulate the development, maturation and functions of the male accessory sex organs like epididymis, vas deferens, seminal vesicles, prostate gland, urethra etc. These hormones stimulate muscular growth, growth of facial and axillary hair, aggressiveness, low pitch of voice etc. Androgens play a major stimulatory role in the process of spermatogenesis and act on the central neural system and influence male sexual behaviour. These hormones produce anabolic effects on protein and carbohydrate metabolism.

(e) Estrogens produce wide-ranging actions such as stimulation of growth and activities of female secondary sex organs, development of growing ovarian follicles, appearance of female secondary sex characters, mammary gland development. Estrogen also regulate female sexual behaviour.

(f) Glucagon is a peptide hormone, and plays an important role in maintaining normal blood glucose levels. Glucagon acts mainly on the liver cells and stimulates glycogenolysis resulting in increased blood sugar. In addition, this hormone stimulates the process of gluconeogenesis which also contributes to hyperglycemia. Glucagon reduces cellular glucose uptake and utilisation. Thus, glucagon is a hyperglycemic hormone.

Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes and enhances cellular glucose uptake and utilisation. As a result, there is a rapid movement of glucose from blood to hepatocytes and adipocytes resulting in decreased blood glucose levels (hypoglycemia). Insulin also stimulates conversion of glucose to glycogen in the target cells. The glucose homeostasis in the blood is thus maintained jointly by the two insulin and glucagons.

Question 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
Solution:
(a) Glucagon and insulin
(b) Parathyroid hormone
(c) LH and FSH
(d) Progesterone
(e) Atrial Natriuretic Factor (ANF)
(f) Testosterone and estradiol

Question 7.
Which hormonal deficiency is responsible for the following:
(a) Diabetes mellitus
(b) Goitre
(c) Cretinism
Solution:
Diabetes mellitus: Insulin deficiency.
Goiter: Deficiency of thyroid hormones due to deficiency of iodine.
Cretinism: Deficiency of thyroid hormones during childhood.

Question 8.
Briefly mention the mechanism of action of FSH.
Solution:
Follicle-stimulating hormone (FSH) and LH Stimulate gonadal activity. In males, FSH and androgens regulate spermatogenesis. In females, FSH is responsible for the growth and development of the ovarian follicles, maturation of egg, and secretion of estrogens

Question 9.
Match the following:
Column I Column II
(a) T4 (i) Hypothalamus
(b) PTH (ii) Thyroid
(c) GnRH (iii) Pituitary
(d) IH (iv) Parathyroid
Solution:
(a) – (ii)
(b) – (iv)
(c) – (i)
(d) – (iii)

VERY SHORT ANSWER QUESTIONS

Question 1.
Give two examples of endocrine glands.
Solution:
Examples of endocrine glands are
(i) pituitary gland
(ii) pineal gland.

Question 2.
Which gland secretes glucagon?
Solution:
Pancreas secretes glucagon.

Question 3.
What is the location of the pituitary gland?
Solution:
The pituitary gland is located in a bony cavity called Sella tursica and is attached to the hypothalamus by a stalk.

Question 4.
Which hormone is secreted by pars intermedia?
Solution:
Pars intermedia secretes melanocyte-stimulating hormone (MSH).

Question 5.
Which hormone is secreted by the pineal gland?
Solution:
Pineal gland secretes melatonin hormone.

Question 6.
Name one disorder caused by hyperfunctioning of the pituitary.
Solution:
Gigantism caused by hyperfunctioning of the pituitary.

Question 7.
How many lobes does the thyroid gland have?
Solution:
The thyroid gland is composed of two lobes which are located on either side of the trachea.

Question 8.
Which gland produces the hormone called thyrocalcitonin (TCT) which regulates the blood calcium levels?
Solution:
Thyroid gland secretes a protein hormone called thyrocalcitonin (TCT) which regulates the blood calcium levels.

Question 9.
Name the organ which secretes progesterone.
Solution:
Ovary secretes progesterone.

Question 10.
Name two hormones of pancreas.
Solution:
Glucagon and insulin are two hormones of pancreas.

Question 11.
Which gland secretes somatostatin?
Solution:
Hypothalamus secretes somatostatin.

Question 12.
Which complex is formed during the binding of hormone to a receptor ?
Solution:
Hormone-receptor complex is formed during the binding of a hormone to a receptor.

Question 13.
Name one hormone secreted by gastro-intestinal tract.
Solution:
Gastrin is secreted by gastro-intestinal tract.

Question 14.
Which hormone is secreted by testes and write the function of hormone also.
Solution:
Testosterone is secreted by testes. It controls growth and development of male secondary
v-sexual characters.

Question 15.
What are membrane bound receptors?
Solution:
Hormone receptors that are present on the cell membrane of the target cells are called membrane bound receptors.

Question 16.
How many types of cells are present in Islets of Langerhans?
Solution:
There are two types of cells present in Islets of Langerhans which are a-cells and P-cells.

Question 17.
Why is oxytocin called as birth hormone ?
Solution:
Oxytocin stimulates the contraction of smooth muscles of uterus and facilitates the child birth.

Question 18.
Why is vasopressin known as antidiuretic hormone?
Solution:
Vasopressin stimulates the reabsorption of water and electrolytes and reduces the loss of water through urine, known as diuresis. Hence it is called as anti-diuretic hormone.

Question 19.
What is cretinism ?
Solution:
Cretinism is reduction in body growth as well as underdevelopment of brain resulting in various structural and functional defects mainly due to deficiency of thyroxine (hypothyroidism) in infants and children.

Question 20.
Which hormone interacts with membrane bound receptor and does not normally enter the target cell?
Solution:
Follicle stimulating hormone interacts with membrane bound receptor and does not normally enter the target cell.

Question 21.
Which hormone opposes parathormone?
Solution:
Thyrocalcitonin opposes parathormone.

Question 22
Which hormone is known as anti-aging hormone?
Solution:
Melatonin, secreted by pineal gland is known as anti-ageing hormone.

SHORT ANSWER QUESTIONS

Question 1.
Discuss the location and function of parathyroid hormone.
Solution:
There are four parathyroid glands present on the back side of thyroid glands, two on each of the lobes of the thyroid gland.
The parathyroid glands secrete parathyroid hormone (PTH), a peptide hormone. Parathyroid hormone (PTH) increases the Ca2+ levels in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/ demineralization. PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from the digested food.

Question 2.
What is progesterone? Name two important functions of progesterone.
Solution:
Progesterone is a steroid hormone secreted by ovary.
Functions of progesterone are as follows:
• It supports pregnancy.
• It acts on mammary glands and stimulates the formation of alveoli (sac-like structures which store milk) and milk secretion.

Question 3.
Name the principal mineralocorticoid secreted by adrenal cortex. Give its any two functions
Solution:
Aldosterone is main mineralocorticoid secreted by adrenal cortex.
Functions of aldosterone are :
• It stimulates reabsorption of Na+ and water.
• It stimulates excretion of K+ and phosphate ions.

Question 4.
What are hormone receptors? What are the modes of their action ?
Solution:
Receptors are specific proteins present on the surface of target cell which bind with hormones and produce physiological changes in cell. Their are two types of hormone receptors which are discussed below:
NCERT Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration 2

Question 5.
Name the gland that functions as a biological clock in our body. Where is this gland located ? Name its one secretion.
Solution:
Pineal gland functions as a biological clock in our body.

  • It is located on the dorsal side of the forebrain.
  • It secretes melatonin.

Question 6.
Where is thymus gland located in the human body ? Describe its role.
Solution:
The thymus gland is a lobular structure located on the dorsal side of the heart and the aorta.
– It secretes hormone thymosin, which has a stimulating effect on the immune system.
– Thymosin promotes proliferation and maturation of T-lymphocytes.

Question 7.
How does insulin act on high glucose content in the blood in a normal human body ?
Solution:
• Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue), and enhances cellular glucose uptake and utilisation. As a result, there is a rapid movement of glucose from blood to hepatocytes and adipocytes resulting in decreased blood glucose levels (hypoglycemia)
• Insulin also stimulates conversion of glucose to glycogen (glycogenesis) in the target cells.
• The glucose homeostatasis in blood is thus maintained jointly by the two enzyme insulin and glucagon.

Question 8.
What is corpus luteum ? Name its one secretion.
Solution:
Corpus luteum is the structure formed by the ruptured ovarian follicles after ovulation.
– It mainly secretes the hormone progesterone.

Long ANSWER QUESTIONS

Question 1.
Explain briefly the structure and functions of middle ear.
Solution:
Calcitonin (from thyroid) : Essential for maintaining bone strength as it does not allow calcium mobilisation from bones. It also lowers plasma level of calcium ifthe same is high. Parathormone: Low level of parathormone secretion decreases blood plasma level of calcium, prevents reabsorption from bones and causes tetany. Higher levels of parathormone (PTH) increase plasma level of Ca2+ by withdrawal from bones resulting in (i) Inflammation and tenderness in bones due to dissolution of calcium from bones, formation of cavities which get plugged with fibrous nodes and cysts (osteitis fibrosa cystica) making bones soft deformed and prone to fracture, (ii) Excess plasma calcium gets deposited in various parts of body which often leads of obstruction and death.

Question 2.
Draw a well labelled diagram showing the location of parathyroid gland. Discuss the function/(s) of parathormone and hyperparathyroidism.
Solution:
NCERT Solutions for Class 11 Biology Chapter 22 Chemical Coordination and Integration 3
Function : Parathormone (Collip’s hormone) regulates the metabolism of calcium and phosphate between blood and other tissue.
(i) Hyperparathyroidism : It leads to demineralisation resulting in softing and bending of bones. An excess of parathormone cause osteoporosis and kidney stones.

Question 3.
What are the causes for following disorders?
(a) Acromegaly
(b) Cretinism
(c) Gigantism
(d) Myxoedema
Solution:
Disorders and their causes.
(a) Acromegaly (Acro-extremity, megaly – large) – It is caused by excess secretion of growth hormone after adulthood is reached.
(b) Cretinism : It is caused by deficiency of thyroid hormone in infant.
(c) Gigantism : It is caused by excess of growth hormone from early age.
(d) Myxoedema: It is caused by deficiency of thyroid hormone in adults.

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 22 Chemical Coordination and Integration, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 22 Chemical Coordination and Integration, drop a comment below and we will get back to you at the earliest.