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

Answer:

1. Exocrine glands. These are the glands with ducts. The secretions of exocrine glands are carried by ducts to a particular organ for some metabolic activity e.g. salivary glands, liver etc.
2. Endocrine glands. These are ductless glands. These glands have no ducts and their secretions get absorbed into the immediate surrounding blood circulation to reach the specific organs to initiate a particular metabolic change. Endocrine glands secrete chemicals called hormones.
3. Hormone. A hormone is a non nutrient chemical which acts as an intercelluclar messenger and is produced in trace amounts. The term hormone was introduced by Starling in 1905. The word ‘hormone’ is derived from a Greek word meaning ‘I excite or arouse’.

Answer:

Endocrine glands of human body.

Various endocrine glands of human beings.
(Testes and ovaries both are shown for convenience

Answer:

1. Hormones of Hypothalamus.
   1. Thyrotropin releasing hormone (TRH)
   2. Growth hormone releasing hormone (GHRH)
   3. Growth hormone inhibiting hormone (GHIH)
   4. Gonadotropin releasing hormone (GnRH)
   5. Prolactin releasing hormone (PRH)
   6. Prolactin inhibiting hormone (PIH)
   7. Adrenocorticotropic releasing hor-mone (CRH)
   8. Melanocyte stimulating hormone releasing hormone (MRH)
   9. Melanocyte stimulating hormone inhibiting hormone (MIH)
2. Hormones of Pituitary
   1. Adrenocorticotropic hormone (ACTH)
   2. Thyroid stimulating hormone (TSH)
   3. Follicle stimulating hormone (FSH)
   4. Luteinizing hormone (LH)
   5. Interstitial cells stimulating hormone (ICSH)
   6. Prolactin or Luteotropic hormone (LTH)
   7. Growth hormone (GH)
   8. Melanocyte stimulating hormone (MSH)
   9. Oxytocin
   10. Vasopressin or Anti diuretic hor-mone (ADH).
3. Hormones of Thyroid
   1. Triiodothyronine (T₃)
   2. Tetraiodothyromine (T₄) or thyroxine.
   3. Calcitonin
4. Hormones of Parathyroid
   1. Parathyroid hormone
5. Hormones of Adrenal
   1. Mineralocorticoids : (Aldosterone mainly)
   2. Glucocorticoids (cortisol mainly cor-ticosterone cortisone)
   3. Gonadocorticoids androgens estrogens
   4. Adrenaline
   5. Noradrenaline.
6. Hormones of Pancreas
   1. Insulin
   2. Glucagon
7. Hormones of Testis
   1. Androgens (testosterone)
8. Hormones of Ovary
   1. Estrogen
   2. Progesterone
9. Hormones of Thymus
   1. Thymosin
10. Hormones of Atrium
    1. Atrial Natriuretic factor (ANF)
11. Hormones of Kidney
    1. Erythropoietin.
12. Hormones of G–I tract
    1. Gastrin
    2. Secretin
    3. Enterogasterone
    4. Cholecystokinin (CCK)
    5. Gastric Inhibitory Peptide (GIP)

Answer:

1. Pituitary Gland
2. Thyroid Gland
3. Adrenal Cortex
4. Gonads
5. Melanocytes of skin.

Answer:

1. Parathyroid hormone (PTH). PTH increases Ca²⁺ levels in the blood. It acts on bones and stimulates the process of bone resorption by deminera-lisation. PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca²⁺ absorption from digested food.
2. Thyroid hormone. They play an important role in the regulation of basal metabolic rate. Thyroid hormone also support the process of red blood cell formation. These control the metabolism of carbohydrates, proteins & fats. They also influence water and electrolyte balance of the body.
3. Thymosins. Thymosins play a major role in the development of the immune system by controlling the differentiation of T- lymphocytes that play a role in cell mediated immunity and also promoting the production of antibodies to provide humoral immunity.
4. Androgens. Androgens regulate the development, maturation and functions of male accessory sex organs like epididymis, vas deferens, seminal vesicles, prostate gland and urethra. These hormones stimulate, muscular growth, growth of facial and axillary hair, aggressive ness, low pitch of voice etc. They also play a stimulatory role in the process of spermatogenesis (formation of spermatozoa) and act on the central nervous system and influence male sexual behaviour. Androgens also produce anabolic effects on protein and carbohydrate metabolism.
5. Estrogens.
   1. Stimulation of growth and activities of female secondary sex organs.
   2. Development of growing ovarian follicles.
   3. Appearance of female secondary sexual characters like high pitched voice, mammary gland development.
   4. Regulation of female sexual behaviour.
6. Insulin and Glucagon.

Insulin is a peptide hormone and plays a major role in regulation of glucose homeostasis. It acts 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 glycogenesis i.e. the conversion of glucose to glycogen in target cells.
Glucagon is a peptide hormone and plays an important role in maintaining the normal blood glucose levels. It acts mainly on the liver cells (Hepatocytes) and stimulates glycogenolysis (break down of glycogen) resulting in increased blood sugar. In addition, this hormone stimulates the process of gluconeogenesis. It reduces cellular glucose uptake and utilisation. It is a hyperglycemic hormone.

Answer:

1. Glucagon and Insulin.
2. Parathyroid hormone, (PTH) increases
3. LH and FSH. Ca⁺⁺ level. Thyrocalcitoxin regulates calcium level
4. Progesterone
5. ANF—Atrial Natriuretic Hormone
6. Testosterone and $\mathrm{\beta }$-estradial

Answer:

1. Insulin
2. Thyroid hormone, thyroxine
3. Deficiency of thyroid hormone, thyroxine, from childhood.

Answer:

Follicle stimulating hormone acts by the action through extracellular receptors. The binding of the hormone with its specific receptor present over the cell surface activates an enzyme called adenylate cyclase. This enzyme converts ATP into cAMP i.e. Adensine triphosphate into cyclic adenosine monophosphate. The cAMP is called the second messenger and carries out various biochemical responses in the cell by activating the existing enzyme system in the cell.
The biochemical responses then lead to physiological responses like ovarian growth.

Answer:

1. (b), 2. (d), 3. (a), 4. (c)