Tiêu đề Chemical Coordination and integration EX-3 Solution fie.docx.pdf ✅

43 CHEMICAL COORDINATION AND INTEGRATION EXERCISE – 3: Achiever’s Section 1. Introduction to Hormones 1. Fill in the blanks. a. The ...1... system provides a point-to-point rapid coordination among organs. b.The ...2... coordination is fast but short-lived. c. As the ...3... do not innervate all cells of the body and the cellular functions need to be continuously regulated; a special kind of coordination and integration has to be provided. This function is carried out by ...4... (a) 1-endocrine system, 2-neural system, 3-nerve fibers, 4-hormones (b) 1-neural system, 2-neural system, 3-nerve fibers, 4-hormones (c) 1-neural system, 2-endocrine system, 3-hormones, 4-neurons (d) 1-endocrine system, 2-neural system, 3-hormones, 4-neurons Ans. (b) Sol. The neural system provides point coordination among organs. Because neurons are connected through synapses and the responses are very quick for any reaction occurring within the body. The neural system coordination is fast but short-lived. For example, feelings of happiness, anxiety, etc. Because the nerve fibres do not innervate all cells of the body and the cellular functions need to be continuously regulated; a special type of coordination and integration becomes important here to be provided. This function is administered by hormones. 2. Which of the following is true? (a) Hormones regulate cellular functions and generally negative feedback regulates hormone levels. (b) The circulating level of hormones is held constant through a series of positive feedback loops. (c) Both lipid soluble hormones and water-soluble hormones bind to intracellular protein receptors. (d) The ducts of endocrine hormones release their content into the bloodstream. Ans. (a) Sol. -Hormones regulate cellular functions and generally negative feedback regulates hormone levels. -The hormone level is not generally maintained through positive feedback loops. -Generally, water soluble hormones bind to extracellular receptors and lipid soluble hormones bind to intracellular receptors. -The endocrine hormones do not have ducts. The endocrine glands release them directly into the surrounding extracellular fluid and from there, they reach into the bloodstream. 2. Human Endocrine System 3. The given table enlists various hormones and their chemical nature. Select the option which completes the table. Hormone Chemical composition (i) Peptide Testosterone (ii) Thyroxine (iii) (iv) Amino-acid derivative (i) (ii) (iii) (iv) (a) Cortisol Steroid Polypeptide Oestradiol (b) Insulin Protein Polypeptide Epinephrine (c) Cortisol Protein Amine Oestradiol (d) Insulin Steroid Amine Epinephrine Ans. (d) Sol. Insulin is a peptide hormone that is produced by the beta cells of islets of Langerhans. Testosterone is an anabolic steroid also known as anabolic-androgenic steroid. Thyroxine is a thyroid hormone derived from the amino acid tyrosine. Epinephrine is an amino acid derivative synthesized in adrenal glands. 4. Fill in the blanks. i. A hypothalamic hormone called a stimulates the pituitary synthesis and release of b .
44 CHEMICAL COORDINATION AND INTEGRATION ii. The c from the hypothalamus inhibits the release of d from the pituitary. (a) a – somatostatin, b – gonadotrophins, c – GnRH, d – growth hormones (b) a – GnRH, b – growth hormones, c – somatostatin, d - gonadotrophins (c) a – somatostatin, b – growth hormones, c – GnRH, d - gonadotrophins (d) a – GnRH, b – gonadotrophins, c – somatostatin, d – growth hormones Ans. (d) Sol. A hypothalamic hormone called GnRH (gonadotropin-releasing hormone) stimulates the pituitary synthesis and release of gonadotropins. The hypothalamic hormone also regulates body temperature. The somatostatin from the hypothalamus has inhibitory functions that inhibit the release of growth hormones from the pituitary. 5. Read the following statements and find out the incorrect statement. a. Adenohypophysis consists of two portions, pars distalis and pars intermedia. However, in humans, the pars intermedia is almost merged with pars distalis. b. The pars distalis is called anterior pituitary and pars intermedia is called posterior pituitary. c. Neurohypophysis is also called pars nervosa, and it stores and releases two hormones called oxytocin and vasopressin (ADH). d. Anterior pituitary releases 9 hormones and pars intermedia releases only one hormone (MSH). e. Pars distalis produces GH, PRL, TSH, ACTH, LH and FSH. (a) a and b (b) b and d (c) d and e (d) c and d Ans. (b) Sol. The pars distalis is called the anterior pituitary whereas the pars nervosa is called the posterior pituitary and not pars intermedia. The anterior pituitary releases six hormones and pars intermedia releases only one hormone (MSH). These six hormones are GH, prolactin, TSH, ACTH, LH, and FSH. 6. Recognize the figure and find out the correct matching. (a) a-pituitary, b-portal circulation, c-pars intermedia, d-hypothalamus, e-sella turcica (b) a-hypothalamus, b-hypothalamic neurons, c-portal circulation, e-posterior pituitary, d-anterior pituitary. (c) a-hypothalamus, b-portal circulation, c- hypothalamic neurons, d-posterior pituitary, e-anterior pituitary (d) a-hypothalamus, b-hypothalamic neurons, c-portal circulation, d-posterior pituitary, e-anterior pituitary Ans. (d) Sol. Hypothalamus- It is responsible for the secretion of hormones. Hypothalamic neurons- Their function is to respond to neural and psychological signals by releasing neurotransmitters and peptide neuromodulators in the brain. The portal system found between hypothalamus and anterior pituitary is known as the hypophyseal portal system. In this portal system, blood flows from capillaries in the hypothalamus into portal veins that carry blood to capillaries of the anterior pituitary. The posterior
45 CHEMICAL CONTROL AND COORDINATION pituitary secretes oxytocin and vasopressin which are transported axonally to it from the hypothalamus. 7. Gull’s disease is due to (a) Decreased production of thyroxine (b) Increased production of thyroxine (c) Excess GH (d) Decreased insulin Ans. (a) Sol. Gull’s disease is due to decreased production of thyroxine. Gull’s disease is also known as myxoedema. It is seen in adults. Symptoms of this disease are hair fall, loose and swollen skin, deposition of adipose fat, and mucus beneath the skin. The patient also becomes sensitive to cold and shows loss of sexual power, mental slowing, bradycardia, and weight gain occurs. Increased production of thyroxine leads to Grave's disease. Excess GH leads to gigantism during childhood and acromegaly in adults. Decreased insulin leads to type-I diabetes. 8. Parathyroid hormone (PTH) increases the Ca 2+ levels in the blood by. i. Bone resorption/dissolution/demineralization ii. Reabsorption of Ca 2+ by the renal tubules iii. Increasing Ca 2+ absorption from the digested food (a) i and ii (b) ii and iii (c) i and iii (d) i, ii and iii Ans. (d) Sol. Parathyroid hormone (PTH) increases the Ca 2+ levels in the blood by bone resorption/dissolution/demineralization, reabsorption of Ca 2+ by the renal tubules and by increasing Ca 2+ absorption from the digested food. 9. Hormones of adrenal cortex and medulla are synthesized from ____ and ____ respectively. (a) Tyrosine, Cholesterol (b) Tryptophan, Tyrosine (c) Cholesterol, Tyrosine (d) Glycoproteins, Cholesterol Ans. (c) Sol. Hormones of the adrenal cortex and medulla are synthesized from cholesterol and tyrosine respectively. Cholesterol is used in the synthesis of steroid hormones like glucocorticoids and mineralocorticoids. These two hormones are released by the adrenal cortex. Hormones released by medulla are commonly known as catecholamines. These are produced by the chromaffin cells in the medulla. These are synthesized from tyrosine which is a non-essential amino acid. 10. Which of the following is incorrect in relation to the catecholamines? (a) These are called emergency hormones or hormones of fight or flight (b) These hormones increase the heartbeat, the strength of heart contraction and the rate of respiration (c) They inhibit the lipolysis and proteolysis (d) They increase alertness, pupillary dilation, piloerection (raising of hairs) and sweating Ans. (c) Sol. Catecholamines support lipolysis and proteolysis. Lipolysis is the process by which fats are broken down in our bodies through enzymes and water or hydrolysis. Proteolysis is the process of hydrolysis of the peptide bonds that hold proteins together, resulting in the breakdown of proteins into their key components, peptides and amino acids. Catecholamines are called emergency hormones or hormones of fight or flight. These hormones increase the heartbeat, the strength of heart contraction and the rate of respiration. They increase sweating, pupillary dilation, piloerection and alertness. 11. Read the following statements and find out the incorrect statement. a. Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis. b. Glucocorticoids stimulate cellular uptake and utilization of amino acids. c. Cortisol is involved in the cardio-vascular system as well as kidney functions. d. Cortisol stimulates the RBC production. e. Aldosterone acts mainly at the renal tubules and stimulates the reabsorption of Na + , K + and water and excretion of phosphate ions.
46 CHEMICAL COORDINATION AND INTEGRATION (a) d and e (b) a and d (c) b and c (d) b and e Ans. (d) Sol. Glucocorticoids stimulate lipolysis, proteolysis, and gluconeogenesis. It does not stimulate cellular uptake rather it inhibits the cellular uptake and utilization of amino acids. Aldosterone is a principal mineralocorticoid. It is secreted when the sodium level is low and by acting on the kidney, it causes more sodium to return to the blood and promotes excretion of potassium. 12. Mark the correct sets. Endocrine Gland Hormone Deficiency Disorder (a) Neurohypophysis Vasopressin Diabetes insipidus (b) Adrenal cortex Corticosteroids Addison’s disease (c) Parathyroid glands Parathormone Myxoedema (d) Thyroid gland Calcitonin Acromegaly (a) b and c (b) c and d (c) a and b (d) a and d Ans. (c) Sol. Vasopressin or ADH is a hormone released by neurohypophysis. When the secretion of this hormone reduces, known as hyposecretion, it leads to a condition known as diabetes insipidus. It reduces the absorption of water, and the urine becomes diluted. Addison’s disease is caused when the corticosteroid hormone’s secretion is reduced which leads to lack of energy, sleep disturbance, etc. Parathormone is released by the parathyroid gland and, but its deficiency does not cause myxedema disorder. Myxedema occurs due to hyposecretion of thyroid hormone in adults. Acromegaly occurs due to hypersecretion of growth hormone in adults. Hence, (c) option is correct. 13. Deficiency of a hormone leads to increase in K + ion and decrease in Na + ion in blood. It is secreted by (a) Zona fasciculata (b) Zona glomerulosa (c) Zona reticulata (d) Zona pellucida Ans. (b) Sol. Mineralocorticoids are the hormones which are responsible for the maintenance of electrolyte balance in the body fluid. These are secreted by the zona glomerulosa of adrenal gland. Zona fasciculata produces glucocorticoids, involved in carbohydrate metabolism. Zona reticulata produces adrenal androgen which are involved in growth of axial, facial and pubic hairs in boys and girls. Zona pellucida is a specialized form of extracellular matrix consisting of glycoproteins, present immediately surrounding the egg plasma membrane. Hence, (b) option is correct. 14. Pituitary gland of adult rats is surgically removed, which of the following endocrine glands will be less affected? (a) Thyroid (b) Gonads (c) Adrenal cortex (d) Adrenal medulla Ans. (d) Sol. If the pituitary gland of an adult rat is surgically removed, then the endocrine gland that is the adrenal medulla will be less affected. This is because the adrenal medulla secretes adrenaline and noradrenaline hormones which are stimulated by the sympathetic and parasympathetic nervous system of the body to induce fight or flight responses in the body. The secretion of adrenaline and noradrenaline from the adrenal gland is not stimulated or inhibited by the secretions of the pituitary gland. They are secreted in response to stress conditions in the body. 15. Read the following statements and find out the incorrect statement. i. Insulin acts mainly on hepatocytes while glucagon acts on both hepatocytes and adipocytes. ii. Glucagon stimulates glycogenolysis and gluconeogenesis. iii. The glucose homeostasis in blood is maintained by both insulin and glucagon jointly. iv. Prolonged hypoglycemia leads to diabetes mellitus which is associated with loss of glucose through urine and formation of harmful compounds known as ketone bodies. v. Diabetic patients are successfully treated with insulin therapy. (a) i and iv (b) ii and iv (c) iii and iv (d) v, i, ii, iv, iii Ans. (a)