31 Years NEET Previous Year Questions: Chemical Coordination & Regulation - 1 - NEET MCQ

The juxtaglomerular cells of kidney produce a peptide hormone called erythropoietin which stimulates erythropoiesis (formation of RBC).

(a) Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue), and enhances cellular glucose uptake and utilisation.
(b) Glucagon acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis resulting in an increased blood sugar (hyperglycemia).
(c) Glucocorticoids stimulate, gluconeogenesis, lipolysis and proteolysis; and inhibit cellular uptake and utilisation of amino acids.
(d) Glucagon hormone stimulates the process of gluconeogenesis which also contributes to hyperglycemia.

Steroid hormones are lipid-soluble and easily pass through the cell membrane of a target cell into the cytoplasm where they bind to specific intracellular receptors (proteins) to form a hormone receptor complex that enters the nucleus. In the nucleus, hormone which interact with intracellular receptors mostly regulate gene expression or chromosome function by the interaction of hormone-receptor complex with the genome. Biochemical actions result in physiological and developmental effects.

Norepinephrine is released by sympathetic fibres i.e, rapidly secreted in response to stress of any kind and during emergency situations. It increases the heart beat, the strength of heart contraction and the rate of respiration.

Insulin is a pe ptide hor mone, 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 utilization. Insulin also stimulates conversion of glucose to glycogen (glycogenesis) in the target cells. 

• Growth hormone secreted by Anterior pituitary
• Cor pus leutum secreted Progesterone
• Oxytocin is secreted by Posterior pituitary

 Iodine is essential for the normal rate of hormone synthesis in  the thyroid. Deficiency of iodine in our diet results in hypothyroidism    and enlargement of the thyroid gland, commonly called goitre.
Hypothyroidism during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, low intelligence quotient, abnormal skin, deaf-mutism, etc.

Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts.
Gastrointestinal tracts secretes four major peptide hormones – gastrin, secretin, cholecystokinin (CCK) and gastric inhibitory peptide (GIP) while juxtaglomerular cells of kidney secretes erythropoietin, a peptide hormone. Releasing and inhibitory hormones are produced by hypothalamus. Neurohypophysis or posterior pituitary is under direct neural regulation of the hypothalamus.

Incomplete dominance is a type of intermediate inheritance in which one allele is not completely dominant over its paired allele. In this, the third phenotype is observed in heterozygous condition. In monohybrid cross with incomplete dominance, the phenotypic and genotypic ratio is 1:2:1, where one part is with dominant phenotype, 2 parts are with intermediate phenotype and 1 part is with recessive phenotype. For example, a snapdragon flower shows red (dominant), white (recessive) and pink (intermediate) flowers. 
Thus, the correct answer is 'Monohybrid cross with incomplete dominance.'

Glucagon is secreted by α cells of islets  of langerhans and stimulate glycogenolysis i.e. breakdown of glycogen into glucose Thymosin hormone secreted from thymus gland stimulates the development of certain kinds of white blood cells involved in producing immunity. It also hostens attainment of sexual maturity.

Cor tisol and testosterone are steroid hormones which are lipid soluble and easily pass through the cell membrane of a target cell and bind to specific intracellular receptor.

Melatonin is a hormone that regulates the 24 hour rhythm of our body such as the sleep-wake cycle etc. Melatonin is produced by pineal gland in the brain, which is responsible for operation and regulation of the biological clock in mammals.

Anterior pituitary secrets growth hormone. Ovary secrets oestrogen hormone. Alpha cells of islets of langerhans secrets glucagon.

Posterior pituitary releases vasopressin which stimulates reabsorption of water in the distal tubules in nephron.

Goitre is caused by deficiency of iodine in diet. Iodine is needed for the synthesis of thyroxine. Toxic agents present in food interfere with thyroxine synthesis and lead to goitre. 

Glucagon is secreted by a-cells of the islets of Langerhans in the pancreas. It increases the concentration of glucose in the blood by stimulating the breakdown of glycogen.

Tetany is caused by reduction in the calcium level due to underactive parathyroid hormone.

Adrenal gland has two parts-cortex and medulla. The medulla is stimulated by sympathetic nervous tissue to produce adrenaline and non-adrenaline while the cortex is stimulated by pituitary hormone to release cortisol, aldosterone and estrogens. Thus injury to adrenal cortex is not likely to affect the secretion of adrenaline

Myxoedema, also known as Gull's disease occurs commonly in adults due to deficiency of thyroid hormones when the mental and physical development of body is complete. Thyroid hormone regulate metabolic rate of body as it increases oxygen consumption in metabolically active tissues. A decreased level of thyroid hormones causes low metabolic rate in body. Other symptoms include increased body weight and water retainment in tissues.
So, the correct answer is 'Myxoedema'.

Parathyroid and adrenal are the endocrine glands. Adrenal glands are the pairs of endocrine glands situated immediately above the kidneys. Hence they are also known as suprarenal glands. Parathyroid glands are the two pairs of endocrine glands -situated behind or embedded within, the thyroid gland in higher  vertebrates.  They  produce parathyroid hormone, which controls the  amount of calcium in the blood.

 A peptide hormone secreted by the parathyroid gland in response to low levels of calcium in the blood. It acts to maintain normal blood levels of calcium by increasing the number of osteoclasts, which break down the bone matrix and release calcium into the blood. It also increases the reabsorption of calcium and magnesium ions in the kideny tubules, so that their concentration is maintained in the blood. 

It is commonly called as ‘emergency hormone’ or 3F – hormone (For fear, fight & flight). Its secretion is regulated by SNS, and not by pituitary as in case of adrenal cortex. It stimulates sweating, heart beat and breathing rate.  It causes the dilation of coronary artery (supplying blood to the heart muscles), bronchioles (for increasing inspiratory volume) and pupil (for better vision).

Parathyroid disorders : It causes the lowering of blood calcium level. This increases the excitability of nerves and muscles causing cramps and convulsions.

Graafian follicle – the ovarian medulla contains many rounded or oval bodies, called ovarian, or grafian follicles, at various stages of development. Each follicle contains a large ovum surrounded by many layers of follicle cells.

Endocrine system, like the nervous system, is meant for internal communication and regulation of the animal body. These two systems operate in a coordinated way on many occasions. Many important functions of the endocrine system are infact, under the control of nervous system. Therefore, the two systems are often collectively called as neuroendocrine system.