Chapter 22 Chemical Coordination and Integration

Class 11 Biology Chapter 22 Important Extra Questions Chemical Coordination and Integration

Chemical Coordination and Integration Important Extra Questions Very Short Answer Type

Question 1.
What is an endocrine gland?
Answer:
The gland without duct, which secretes hormones, is called the endocrine gland.

Question 2.
What are hormones?
Answer:
The endocrine glands secrete chemical substances which affect various body activities in target organs, by reaching there through blood.

Question 3.
Expand the term BMR.
Answer:
Basal Metabolic Rate.

Question 4.
Which hormone is responsible for the metamorphosis of tadpoles into adult frogs?
Answer:
The hormone thyroxine secreted by the thyroid gland is responsible for the metamorphosis of tadpoles into adult frogs.

Question 5.
What is castration?
Answer:
The surgical removal of the testis is called castration.

Question 6.
What is adrenal virilism?
Answer:
The hypersecretion of sex corticoids causes the development of external male characters in females, called adrenal virilism.

Question 7.
What condition is caused due to failure of production of [ testosterone?
Answer:
Eunuchoidism.

Question 8.
What function do glucagons have?
Answer:
It causes the formation of glucose from the breakdown of glycogen and from amino acids.

Question 9.
Name the gland which functions as both the endocrine and exocrine?
Answer:
Pancreas.

Question 10.
Name the hormone which is antidiuretic in its effect.
Answer:
Vasopressin (ADH) secreted by the posterior pituitary.

Question 11.
Why pituitary is called, “master gland”?
Answer:
Because it controls most of the other endocrine glands.

Question 12.
How are pheromones different from hormones?
Answer:
Hormones affect the same individual but pheromones affect another individual of the community.

Question 13.
Give one example of the effect of pheromones in Insects.
Answer:
Pheromones from female moths attract males from 3 – 4 km distance.

Question 14.
How is iodine important to our body?
Answer:
Iodine is required for thyroxine secretion. Deficiency of iodine leads to goiter.

Question 15.
Name the gland which is both exocrine and endocrine.
Answer:
Pancreas.

Question 16.
Write any two hormones which are chemically different.
Answer:
Insulin hormone is made of proteins and testosterone is made of steroids.

Question 17.
Write the full form of ACTH. What is its role?
Answer:
Andreno-Cortico-Trophic Hormone.
ACTH stimulates the secretion of the adrenal cortex.

Question 18.
Write names and sources of hormones regulating the plasma Ca⁺ level.
Answer:
Parathormone produced by parathyroids.

Chemical Coordination and Integration Important Extra Questions Short Answer Type

Question 1.
Work out the contrast between diabetes Mellitus and diabetes insipidus.
Answer:
Diabetes Mellitus: It is the disorder in which blood sugar is present well beyond the renal threshold, consequently glucose is present in urine. It is caused due to deficiency of insulin hormone.

Diabetes insipidus: It is the disorder in which hypotonic urine is excessively excreted. It is caused by the deficiency of the secretion of the ADH hormone.

Question 2.
Differentiate between estrogen and progesterone.
Answer:

Estrogen	Progesterone
(1) It is secreted by the ovary.	(1) It is secreted by the Corpuslutem of the ovary.
(2) It acts on and develops female secondary organs.	(2) It maintains endometrium during pregnancy.

Question 3.
Differentiate the action of insulin and glucagon.
Answer:

Insulin	Glucagon
(1) It is secreted by beta cells of islet of Langerhans of the pancreas.	(1) It is secreted by alpha cells of islet of Langerhans of the pancreas
(2) It converts soluble glucose into insoluble glycogen.	(2) It converts glycogen into glucose.

Question 4.
Name and state briefly the functions of the hormones secreted by the adrenal cortex.
Answer:
Mainly the hormones secreted by the adrenal cortex are:

1. Glucocorticoids: These regulate the metabolism of carbohydrates, fats, and proteins.
2. Mineralocorticoids: These maintain the sodium, potassium level in the blood.
3. Sex corticoids: These stimulate the development of external sex characters like male patterns of body hair distribution. Androstenedione and dehydroepiandrosterone are sex corticoids.

Question 5.
Differentiate between hormones and pheromones.
Answer:

Hormones	Pheromones
1. These are the chemicals released by the endocrine glands.	1. These are the chemicals released by exocrine glands.
2. These are the result of biological changes in the body.	2. These are the result of behavioral and developmental changes.
3. Biological changes are the manifestation of the individual self.	3. Changes are after perception of these by the members of the same species.
4. These are released into the bloodstream	4. These are released into the environment.

Question 6.
Describe different disorders caused by thyroid hormone imbalance.
Answer:
Other than simple goiter, the main thyroid hormone imbalances are:

1. Cretinism: Hypoactivity of thyroxine in children causes poor physical and mental development, low metabolism. The affected individual is potbellied and pigeon-chested.
2. Myxedema: Hypoactivity of thyroxine in adults causes poor physical and mental development, low metabolism, puffy appearance, and reproductive failure.
3. Grave’s disease: (exophthalmic goiter) Hyperactivity of thyronine causes increased metabolism, bulging of eyeballs, emaciation, and restlessness.

Question 7.
State different functions of thyroid hormones.
Answer:

1. These affect the metabolism.
2. These maintain BMR (Basal Metabolic Rate).
3. These affect physical growth.
4. These affect the development of mental faculties.
5. These affect the process of differentiation.
6. Affect metamorphosis in tadpoles.

Question 8.
State chief characteristics of the hormones.
Answer:

1. The effect produced is marked even in minute concentrations.
2. Directly sent to target organs through blood circulations.
3. Storage is not possible.
4. The target organ is distantly placed from the organ in which these are produced.
5. These are secreted as a response to some sort of stimulus.
6. Chemicals are biological in origin, i.e., biogenic, e.g., amine, peptides, steroids, etc.

Question 9.
Differentiate between hormones and enzymes.
Answer:

Hormones	Enzymes
1. Produced by gland distant from target organ.	1. Produced at the site of action.
2. Maybe steroids, amines, or peptides.	2. Proteinaceous in nature.
3. Consumed during the action.	3. Not used up during the auction.
4. Do not catalyze the specific reaction.	4. Catalyses specific reaction.
5. Affect the activity of enzymes	5. Does not affect the activity of hormone production.

Question 10.
Describe in brief different disorders caused by the adrenal cortex.
Answer:
Different disorders related to the adrenal cortex are:

1. Addison’s disease: Atrophy or destruction of adrenal cortex causes failure of secretion of minerals corticoids and glucocorticoids leads to low blood Na⁺, high plasma K⁺ and urinary Na⁺, bronze skin pigmentation.
2. Cushing’s syndrome: Increased production of cortical causes low’ plasma K⁺, high plasma Na⁺, rise in blood pressure and volume.
3. Aldosteronism: Hyperactivity of aldosterone cause Na+ and K+ conditions like Cushing’s syndrome, muscular weakness.
4. Adrenal virilism: Hypersecretion of sex corticoids causes the development of male-type external features in female-like beard and mustache, low pitch male voice, and mensural cessation.

Question 11.
Why do you suppose the brain goes to the trouble of synthesizing releasing hormones, rather than simply directing the production of the pituitary hormones immediately?
Answer:
Hormones secreted by the posterior lobe of the pituitary gland are actually synthesized by the neurons in the hypothalamus and stored in their axon ends in the posterior lobe for release, when required.

The pituitary was called the Master endocrine gland, because of the number of hormones it produces and the control it exercises over other endocrine glands. However, it itself is under control of the releasing hormones secreted by the hypothalamus of the brain. Thus there is a chain of disorders, the hypothalamus directs the pituitary output, which controls the secretion of hormones by other endocrine glands.

Question 12.
Which endocrine gland is controlled by the secretion of other endocrine glands?
Answer:
The thyroid gland is the only endocrine gland that is controlled by the secretion of another endocrine gland. It stores its secretary product in large quantity.

Homopothalamus, in response to some external stimulus, produces a thyrotropin-releasing hormone (TRH) for the secretion of the thyrotrophic hormone. The thyrotropin-releasing hormone stimulates the anterior pituitary lobe to secrete thyrotrophic hormone. The latter, in turn, stimulates the thyroid gland to produce thyroxine, thereby restoring the normal blood- thyroxine level.

Question 13.
How is the communication among the parts of an organism accomplished?
Answer:
The endocrine system functions in a hierarchical manner. The hypothalamus produces releasing or inhibiting hormones, which travel in neurosecretory cells to the anterior pituitary, where they control the production of its hormones.

Hypothalamus also produces two hormones which are stored in and released from the posterior pituitary level. Many hormones are regulated by negative feedback controls. In such a Control, an excess of the hormone or the product of hormone-induced response suppresses the synthesis or release of that hormone until the level returns to normal.

In positive feedback control, the hormone causes an event or process that increases the production of this hormone. Thyroid and steroid are lipid-soluble hormones and readily pass through the plasma membrane of a target cell into the cytoplasm.

There they bind to the specific intracellular receptors and binds to specific regulatory sites on the chromosomes. The binding alters proteins, forming a complex that enters the nucleus the pattern of gene expression, initiating the transcription of some genes (DNA) while repressing the transcription of others. This results in the production of specific RNA, translation products, proteins, and enzymes. In this way communication among the parts of an organism accomplished.

Question 14.
Discuss the role of the hypothalamus and pituitary as a coordinated unit in maintaining physiological processes.
Answer:
The hypothalamic-pituitary axis consists of the hypothalamus and pituitary gland. The hypothalamus is a part of the brain and consists of several masses of grey matter called Hypothalamic nuclei. These are located in the white matter in the floor of the third cerebral vesicle of the brain; neurons of these hypothalamic nuclei control the pituitary gland.

The pituitary gland is a small pea-shaped gland situated below the hypothalamus and connected to the brain by a stalk. The pituitary is divided into anterior, posterior, and intermediate lobes. It secretes a number of hormones.

Question 15.
Why is the endocrine system considered a chemical extension of the nervous system?
Answer:
The human endocrine system and functioning of their hormones, including their role as chemical messenger and regulators. Also, it is related to the hypothalamic-hyperphysical axis and feedback controlling mechanism. These two systems operate in a co-ordinate way on many occasions. Many important functioning of the endocrine system is under the control of the nervous system. Hence the endocrine system is considered as a chemical extension.

Question 16.
What are the seven principal hormones produced by the anterior pituitary? What function does each serve?
Answer:

Hormone	Function
1. Somatotropin or growth hormone	1. It stimulates body growth.
2. Thyrotropin or thyroid-stimulating hormone.	2. Release of thyroid hormones.
3. Corticotropin or Adreno-corticotropin hormone	3. Release of gluco-corticoids and mineralo corticoids hormones of adrenal cortex.
4. Follicle-stimulating hormone (FSH).	4. Growth of ovarian follicle and estrogens secretions in females and spermatogenesis in males.
5. Prolactin Hormone	5. Milk secretion from mammary glands.
6. Luteinizing hormone (LH)	6. It stimulates the ovaries to secrete the female sex hormone- progesterone.
7. Melanocyte -stimulating hormone (MSH)	7. Melanocyte-stimulating hormone-releasing hormone. The target organ is skin pigment cells.

Question 17.
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 18.
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 19.
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 20.
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 21.
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 22.
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 23.
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.

Chemical Coordination and Integration Important Extra Questions Long Answer Type

Question 1.
What are thyroids? Describe the disorders of thyroids hor¬mones.
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 2.
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 3.
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