NCERT MOST IMPORTANT QUESTIONS CLASS – 11 | BIOLOGY IMPORTANT QUESTIONS | CHAPTER -22 | CHEMICAL COORDINATION AND INTEGRATION | EDUGROWN |

In This Post we are  providing Chapter-22 CHEMICAL COORDINATION AND INTEGRATION NCERT MOST IMPORTANT QUESTIONS for Class 11 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MOST IMPORTANT QUESTIONS ON CHEMICAL COORDINATION AND INTEGRATION

Question 1.
What hormones are secreted by the posterior pituitary gland? What function do they serve? Where are these hormones actually produced? How these hormones are transported to the region from which they are released?
Answer:
1. Vasopressin: Released from the axon terminals of hypothalamic neurons into the blood in the posterior lobe of the pituitary. It reduces the volume of urine by increasing the reabsorption of water from the urine, collecting tubules, and collection ducts in the kidney, hence called Antidiuretic hormone.

2. Oxytocin: It is released from the axon terminals of hypothalamic neurons into the blood in the posterior lobe of the pituitary due to the distension of the uterus by the full-term fetus.

It helps in childbirth. It is also known as milk ejection hormone.

Question 2.
What are the examples of antagonistic hormones associated with basal metabolism? How does each pair function?
Answer:
Para hormone (PTH) and thyroid hormone calcitonin act agonistically to regulate the calcium phosphorous balance in the blood. The release of parathormone increases the blood calcium to normal by drawing calcium from the bones into the plasma, by increasing calcium absorption in the digestive tract, and by reducing loss of calcium in the urine. It lowers calcium-phosphorus balance and is necessary for the growth of bones and teeth.

Calcium is vital for blood clotting, muscle tone, and for normal nervous activity. It is also needed for the activities of many enzymes.

Question 3.
What two hormones are produced by the adrenal medulla? What non-hormonal function do they serve?
Answer:
The hormone Adrenaline and Nor-adrenaline are secreted by the adrenal medulla.
Function: These hormones act on organs and tissues supplied by sympathetic fibers and produce effects like those of sympathetic stimulation.

Question 4.
From what chemical compounds are ail steroid hormones derived? Mention at least two examples of steroidal hormones.
Answer:
The adrenal cortex is the outer layer of the adrenal gland. It secretes steroidal hormones. Examples, Glucocorticoids, and mineralocorticoids.

The adrenal cortex produces steroid hormones through the modification of cholesterol.

Question 5.
In general, how the steroid hormones affect changes in their target cells?
Answer:
Steroid hormones have minor differences, the various hormones have strikingly different functions. They bind to different receptors in the target cell and affect sets of chemical reactions.

Cortical steroids can be grouped into three functional categories.

1. Mineralocorticoids: They regulate saltwater balance through their effect on kidney and blood pressure.
2. Glucocorticoids: They regulate carbohydrate, protein, and lipid metabolism.
3. Ganado corticoids: It is a sex hormone and helps chemically and functionally to the sex.

Question 6.
What hormones are produced when the body’s blood glucose levels drop below normal? How do these hormones act to return the level to normal? What hormone is produced when the body’s blood glucose levels become elevated? How does this hormone act to return the level to normal?
Answer:
B-cells secrete insulin.
T-cells secrete somatostatin.

These two hormones regulate the level of glucose in the blood:

1. When the blood glucose level becomes excessive, insulin acts on the three target tissues: liver, muscle, and adipose cells. Insulin causes the liver to take up glucose and convert it into glycogen and fat. It facilitates the liver to take up glucose in the muscle and adipose cells causing the levels of the glucose in the blood lowered.
2. Somatostatin: acts as a paracrine, to inhibit the secretion of glycogen and insulin, decreases secretion, mortality, and absorption in the digestive tract.

Question 7.
What is diabetes? What is the ultimate hormonal deficiency in these diseases? How does this affect an individual’s ability to use glucose? What are some possible treatments for adult-onset diabetes?
Answer:
Diabetes mellitus is a group of disorders that lead to an increase in the level of glucose in the blood. The deficiency of insulin hormone causes diabetes mellitus.

In this disease, the patient cannot use or store glucose. Thus, glucose accumulates in the blood from where it is excreted by kidneys in die urine.

Glucose increases the osmotic pressure of urine, causing loss of water from the body in urine. This produces excessive thirst. Degradation of fats increases, producing ketone bodies such as acetoacetate and acetone. Blood cholesterol rises, injuries may change into gangrenes. Healing power is ^ impaired leading to the damage of tissues.

A diabetic person has blurred vision and is weak, tired, irritable, nauseated, and underweight. In extreme cases, the patient may pass into a coma and die.

Treatment: Administration of insulin gives relief by lowering blood glucose levels.
Diabetes caused by insufficient insulin production is called Insulin-dependent diabetes.
Diabetes due to a person’s ability to use insulin is termed as insulin ) independent diabetes. It is more common than insulin-dependent diabetes.
Diabetes mellitus may also be caused by the failure of insulin to move glucose from the blood into the cells for storage or consumption.

This is due to the defective insulin receptors or cell surfaces, starving the cells of glucose, or to an abnormality in pancreatic protein amylin, which regulates insulin’s activity.

Question 8.
What are thyroids? Describe the disorders of thyroids hormones.
Answer:
The thyroid gland is situated in the neck close to the trachea in human beings. It consists of two elongated oval lobes joined together by a narrow band called ISTHMUS. It highly vascular organ and contains many- spherical or oval sac-like follicles.

Cells of the follicle secrete jelly-like semi-fluid called Colloid of Thyroid stored in the lumen of the follicle. This contains iodinated forms of an amino acid called THYRONINE. When required, two thyroid hormones, THYROXINE, and TRIIODOTHYRONINE are released from the colloid to the blood.

(a) and (b) Thyroid gland

Disorders:

1. Failure of the thyroid from infancy or childhood causes a disease called cretinism. In it, there is slow body growth and mental development. There is also a low metabolic rate.
2. The deficiency of thyroid hormones in adults produces Myxedema. The patient shows a puffy appearance and lacks intelligence, lateness, and initiative. There is also a low metabolic rate.
3. The deficiency of iodine produces enlargement of thyroids causing Iodine Deficiency to Goitre.
4. Some thyroid enlargement is accompanied by a bulging of the eyeball.
   The disease is called Grave’s Disease or Exophthalami Goitre. The excessive amount of thyroid is secreted. ,

Question 9.
Give an account of the primary male sex organ in man and mention briefly the functions of the hormone testosterone.
Answer:
The testis is the primary sex organ. There are pair of tests. Each testis is covered by a thick connective tissue sheath, Tunica Albuginea. Both testes normally remain suspended in a pouch called Scrotum outside the abdominal cavity. Each testis consists of many small and highly convoluted tubules, called seminiferous tubules, constituting its spermatogenic tissue.

Cells lining the tubules give rise to spermatozoa, which are released into the lumen of the tubule. These are present groups of polyhedral cells.

Interstitial cells of Leydig in the connective tissue around the seminiferous tubules. This constitutes the endocrine tissue of the testis. These cells secrete Testosterone into the blood. Somniferous tubules unite to form a large number of straight tubules, which open into irregular cavities in the posterior part of the testis. The vasa efferentia arise from these cavities and conduct spermatozoa out from the testis.

Functions of Testosterone:

1. It stimulates the growth and development of male secondary sex organs (prostate, seminal vesicles, and penis).
2. It stimulates and maintains the normal function of secondary sex organs in reproduction.
3. It also stimulates and maintains the development of external male characters such as beards, mustaches, and low-pitch male voices in males and combs and wattles in cock.
4. It also stimulates the formation of sperms in the testes.
5. It promotes the growth of many body tissues including bones and muscles.

T.S. of testis of an adult man

Question 10.
Distinguish between
(a) Follicle-stimulating hormone and luteinizing hormone.
Answer:
Follicle-stimulating hormone and luteinizing hormone:

Stimulating hormone (FSH)	Luteinizing hormone
(i) It stimulates the testes in the male to produce sperms.	(i) It stimulates the testes to secrete the male sex hormone.
(ii) It stimulates the ovaries in the female to produce ova.	(ii) It stimulates the ovaries to secrete the female sex hormone- progesterone.

(b) Somatostatin and somatomedin
Answer:
Somatostatin and somatomedin:

Somatostatin	Somatomedin
(i) It is secreted by the anterior lobe of the pituitary.	(i) It is secreted by the hypothalamus.
(ii) It stimulates body growth	(ii) It inhibits the secretion of the growth hormone from the anterior pituitary.

(c) Vasopressin and Oxytocin
Answer:
Vasopressin and Oxytocin:

Vasopressin	Oxytocin
(i) Vasopressin is released from the axon terminal of hypothalamic neurons into the blood in the posterior lobe of the pituitary due to the rise in blood osmotic pressure caused by the loss of water from the body.	(i) Oxytocin is released from the axon terminals of hypothalamic neurons into the blood in the posterior lobe of the pituitary due to distension of the uterus by the full-term fetus or due to the sucking of the breast by an infant.
(ii) It reduces the volume of urine by increasing the reabsorption of water from the urine in the distal convoluted tubules, collecting tubules, and collection ducts in the kidney, hence called Antidiuretic Hormone (ADH).	(ii) It helps in childbirth by causing uterine contractions at the end of pregnancy, hence called birth hormones.
(iii) It increases arterial blood pressure by causing constriction or narrowing of arterioles.	(iii) It causes the contractions of the mammary gland and muscles that help in the flow of stored milk from the mammary gland to the mouth of the sucking infant, hence called milk ejection hormone.

(d) Estrogen and progesterone
Answer:
Estrogens and Progesterone:

Estrogens	Progesterone
(i) These are secreted by the cells of maturing Grrafian follicle.	(i) Corpus luteum and placenta secrete progesterone.
(ii) Estrogen stimulates growth, maturation, and functions of female secondary sex organs at puberty.	(ii) Progesterone brings about most of the pregnancy changes such as uterine growth, attach¬ment of the embryo to the uterine wall, placenta formation.
(iii) These also develop and maintain external female sex characters like the high pitch female voice and the female pattern of body hair distribution.	(iii) No such action.

(e) Glucocorticoids and mineralcorticoids
Answer:
Glucocorticoids and Mineralocorticoids:

Glucocorticoids	Mineralocorticoids
(i) Glucocorticoids such as cortisols regulate the metabolism of carbohydrates, fats, and proteins.	(i) Mineralocorticoids such as Aldosterones regulate the metabolism of sodium and potassium.
(ii) These are secreted from the middle cellular layer (ZONA Fasciculate) of the adrenal cortex

(f) Diabetes mellitus and diabetes insipidus
Answer:
Diabetes mellitus and Diabetes insipidus:

Diabetes mellitus	Diabetes insipidus
(i) It is due to failure of insulin secretion.	(i) It is due to the failure of secretion of vasopressin.
(ii) The blood sugar is abnormally high and the glucose appears in the urine.	(ii) The blood sugar is normal and no glucose appears in the urine.
(iii) There are high blood cholesterol and ketone body formation.	(iii) There is no such phenomenon.

(g) Exophthalamia goiter and iodine deficiency goiter
Answer:
Exophthalmic Goitre and Iodine Deficiency goiter:

Exophthalmic Goitre	Iodine Deficiency goiter
(i) It is accompanied by a bulging of eyeballs, i.e., exophthalmos.	(i) It is accompanied by cretinism in children and myxedema in adults.
(ii) The thyroid is overactive and secretes an excessive amount of thyroid hormones.	(ii) The dietary deficiency of iodine causes the deficiency of thyroid hormones.

(h) Cretinism and dwarfism.
Answer:
Cretinism and dwarfism:

Cretinism	Dwarfism
(i) It is due to over secretion of so gonadotropin from childhood.	(i) It is due to the failure of secretion of somatotropin from an early age.
(ii) There is an abnormal elongation of all long bones.	(ii) There is stoppage of growth of long bones and of the body prematurely making the patient dwarf