FREE NEET Biology Practice MCQ Test: Chemical Coordination And Integration Exercise 3 Questions Answers With Detailed Explanations [PDF]

Answer: (c)

Pancreas being an endocrine gland, releases insulin into the blood. Insulin maintains the normal blood sugar level.

Answer: (c)

Epinephrine or adrenaline, norepinephrine or noradrenaline and acetylcholine are the neuro-transmitters. These are released by the nerve fibres to transmit the impulse to the next neurone. Cortisone is not the neurotransmitter.

Answer: (a)

FSH (Follicle Stimulating Hormone), secreted by anterior pituitary gland, is a gonadotrophic hormone. It stimulates spermatogenesis and growth of seminiferous tubules in testes in male and maturation of Graafian follicle and secretion of estrogen and progesterone from corpus luteum in female

Answer: (c)

Answer: (c)

Gonadotropin releasing hormone (GnRH) is secreted by the hypothalamus which stimulates the anterior lobe of pituitary gland to secrete luteinising hormone (LH) and Follicle Stimulating Hormone (FSH).

Answer: (c)

Answer: (a)

Answer: (d)

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.

Answer: (a)

Answer: (c)

Enterogastrone is secreted by duodenal epithelium and it slows gastric contractions to delay its emptying and also stops secretion of gastric juice. Gastrin stimulates secretion of gastric juice. Cholecystokinin stimulates release of enzymes in pancreatic juice and release of bile from gall bladder. Cholecystokinin is also known as pancreozymin.

Answer: (d)

Steroid hormones such as cortisol, testosterone, estradiol and progesterone, mostly regulate gene expression or chromosome function by the interaction of hormonereceptor complex with the genome. So, these easily pass through the cell membrane of the target cell and bind to a receptor inside it.

Answer: (c)

Releasing and inhibiting factors are released by hypothalamus. The hypothalamus is connected to adenohypophysis by hypophysial portal vein and is connected to the neurohypophysis by axons of neurosecretory cells. Hence, neurohypophysis is directly under the neural control. The cardiocytes of atria of the heart secrete peptide hormone, called atrial natriuretic factor (ANF) in response to an increased return of the deoxygenated (venous) blood. The liver produces angiotensinogen which is changed to angiotensin II by an enzyme renin secreted by juxtaglomerular apparatus (JGA).

Answer: (b)

Answer: (c)

Hormone action involves their reception by target cells. Specific proteins called hormone receptors that are located in target tissues only bind with these hormones. Hormone receptor may be of two types: membrane bound receptor and intracellular receptors. Steroid hormones etc., bind with intracellular receptors while some hormones e.g., pituitary hormones like FSH etc., bind with membrane bound receptors.

Answer: (b)

Answer: (c)

Thymus starts functioning in the embryonic stage itself, becomes active during childhood and undergoes regression and gradually stops functioning in old individuals. So, production of thymosins decreases. As a result, immune responses of old persons become weak.

Answer: (a)

Hormones are chemical messengers formed by endocrine cells. Chemically hormones are of the following types: Amines–composed of amino group e.g., Melatonin.

• Amino acids –eg. thyroxine
• Peptides – eg. insulin
• Steroids –eg. Aldosterone

Answer: (d)

Diabetes mellitus is caused by the deficiency of hormone insulin which is secreted by pancreas. Insulin lowers the blood-glucose level. Deficiency of antidiuretic hormone (ADH) leads to diabetes insipidus.

Answer: (b)

Vasopressin reduces water loss through urine by stimulating resorption of water by the distal tubules of the kidney. Glucagon is released from a-cells. Prolactin is produced from anterior pituitary.

Answer: (c)

Acromegaly is caused by excess of STH (somatotrophic hormone), released by anterior lobe of pituitary after adolescence. The bones of the lower jaw and limbs become abnormally enlarge but the body does not attain a giant stature. Excess of thyroxine causes cretinism and myxoedema. Excess of adrenaline causes increased BMR (Basal Metabolic Rate), heart beat, excitement, etc.