NEET Biology Chemical Coordination and Integration MCQs Set 03

Answer: (d) Gigantism & Acromegaly

Explanation:
1. Hypersecretion of somatotropin (GH) causes gigantism in childhood and acromegaly in adults.
2. Dwarfism is due to hyposecretion.

Teacher's Note:
1. Gigantism before epiphyseal closure.
2. Acromegaly after closure.

Answer: (a) Excess of S.T.H.

Explanation:
1. Acromegaly is caused by excess growth hormone (STH) in adults, enlarging the face, hands and feet.
2. Thyroxine or adrenaline excess does not cause it.

Teacher's Note:
1. Excess GH in childhood: gigantism.
2. Excess GH in adulthood: acromegaly.

Answer: (a) Hypothalamus

Explanation:
1. Vasopressin is synthesised by neurosecretory cells of the supraoptic nucleus of the hypothalamus.
2. The posterior pituitary only stores and releases it.

Teacher's Note:
1. Oxytocin is made mostly in the paraventricular nucleus.
2. ADH is made in the supraoptic nucleus.

Answer: (c) Somatotrophic hormone

Explanation:
1. Somatotrophic hormone (GH) promotes protein synthesis and skeletal growth.
2. Iodothyroxine acts on metabolism and LH on gonads.

Teacher's Note:
1. STH stimulates liver to make somatomedins.
2. These act on bone growth.

Answer: (d) F.S.H.

Explanation:
1. FSH stimulates ovarian follicle cells to secrete estrogen.
2. LH mainly drives ovulation and progesterone secretion.

Teacher's Note:
1. FSH to estrogen.
2. LH to progesterone after ovulation.

Answer: (c) Posterior pituitary

Explanation:
1. The posterior pituitary releases hormones under direct nerve control from the hypothalamus.
2. Anterior pituitary is controlled by releasing hormones through the portal system.

Teacher's Note:
1. Neurohypophysis secretion is neural.
2. Adenohypophysis secretion is hormonal.

Answer: (c) A,C,D

Explanation:
1. A is true: the pars distalis makes GH, PRL, TSH, ACTH, LH and FSH.
2. B is false because pars intermedia secretes MSH, not melatonin.
3. C and D are true, so the correct combination is A, C, D.

Teacher's Note:
1. Pars intermedia is reduced in humans.
2. Melatonin comes from the pineal gland.

Answer: (b) OT, PRL and FSH

Explanation:
1. Oxytocin ejects milk, prolactin stimulates milk production and FSH stimulates growth of ovarian follicles.
2. The sequence OT, PRL, FSH matches the question.

Teacher's Note:
1. OT: let-down reflex.
2. PRL: milk synthesis.

Answer: (a) a-v, b-iv, c-i, d-ii

Explanation:
1. FSH matures the Graafian follicle; LH develops the corpus luteum.
2. Progesterone prepares the endometrium for implantation; estrogen develops female secondary sexual characters.

Teacher's Note:
1. Uterine contraction is not in the list of correct pairs.
2. Option a-v, b-iv, c-i, d-ii is correct.

Answer: (b) Anterior lobe of pituitary gland

Explanation:
1. FSH is produced by the anterior lobe of the pituitary.
2. The adrenal cortex makes corticoids and the posterior lobe stores ADH and oxytocin.

Teacher's Note:
1. Anterior pituitary = tropic hormones.
2. Posterior = release only.

Answer: (b) TSH

Explanation:
1. TSH secretion is controlled by feedback: high T3 and T4 reduce TSH release.
2. Oxytocin and vasopressin are not controlled this way and cortisone is not an adenohypophysis hormone.

Teacher's Note:
1. Negative feedback keeps hormone levels stable.
2. TRH from the hypothalamus raises TSH.

Answer: (a) acidophilic cells

Explanation:
1. Somatotrophs that secrete growth hormone are acidophilic cells.
2. Basophilic cells secrete the glycoprotein tropic hormones.

Teacher's Note:
1. Acidophils: GH and prolactin.
2. Basophils: FSH, LH, TSH, ACTH.

Answer: (b) Over secretion of growth hormone in adulthood

Explanation:
1. Acromegaly is due to excess growth hormone after the growth period (adults).
2. Excess in childhood causes gigantism instead.

Teacher's Note:
1. Bones of face, jaw, hands and feet thicken.
2. Long bones cannot lengthen after epiphyseal closure.

Answer: (b) Diabetes insipidus

Explanation:
1. ADH absence leads to diabetes insipidus with excessive dilute urine and thirst.
2. Diabetes mellitus is linked to insulin and acromegaly to growth hormone.

Teacher's Note:
1. Insulin deficiency: diabetes mellitus.
2. ADH deficiency: diabetes insipidus.

Answer: (b) Two

Explanation:
1. (a) False: parathyroid glands lie on the back of the thyroid.
2. (b) False: PTH is a peptide, not a steroid.
3. (c) and (d) are true, so two statements are correct.

Teacher's Note:
1. PTH raises blood calcium.
2. It stimulates bone resorption and renal reabsorption.

Answer: (c) Thyroxine

Explanation:
1. Thyroxine increases oxygen consumption and the metabolic rate.
2. STH, insulin and testosterone do not mainly raise BMR.

Teacher's Note:
1. Thyroxine is the calorigenic hormone.
2. It also supports normal growth.

Answer: (b) Myxoedema

Explanation:
1. Hypothyroidism in adults causes myxoedema with low BMR, weight gain and puffy skin.
2. Cretinism is hypothyroidism in infants.

Teacher's Note:
1. Adult: myxoedema.
2. Child: cretinism.

Answer: (b) Hypocalcaemia

Explanation:
1. Parathormone deficiency lowers blood calcium, called hypocalcaemia.
2. This causes tetany of muscles.

Teacher's Note:
1. Low PTH: hypocalcaemic tetany.
2. High PTH: weak bones.

Answer: (a) Parathyroid hormone

Explanation:
1. Collip isolated parathyroid hormone (parathormone) in 1925.
2. Thyroxine was isolated by Kendall.

Teacher's Note:
1. Collip's hormone = PTH.
2. Remember the name with the hormone.

Answer: (d) Isthumus

Explanation:
1. The isthmus is the thin band of tissue joining the two lobes of the thyroid in front of the trachea.
2. The other names are not anatomical terms.

Teacher's Note:
1. Thyroid has two lobes on either side of trachea.
2. Isthmus connects them.

Answer: (a) Tetany

Explanation:
1. Removal of the parathyroids lowers blood calcium and causes tetany (muscle spasms).
2. Myxoedema is thyroid, and Simmond's and Addison's are pituitary and adrenal disorders.

Teacher's Note:
1. Hypoparathyroidism: tetany.
2. Hyperparathyroidism: bone loss.

Answer: (d) Weaker bones due to increased removal of cal- cium from them

Explanation:
1. Excess PTH removes calcium from bone and raises blood calcium.
2. The bones become weak and brittle.

Teacher's Note:
1. Osteoporosis risk.
2. Kidney stones may form.