Chemical Coordination and Integration MCQs

Read the following statements regarding MSH, Oxytocin, and Vasopressin:

I. MSH acts on the melanocytes and regulates pigmentation of the skin.
II. Oxytocin acts on the smooth muscles of our body and stimulates their contraction.
III. In females, vasopressin stimulates vigorous contraction of the uterus during childbirth and milk ejection from the mammary gland.
IV. Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules.

Identify the correct statement combination.

Read the statements regarding hormonal disorders of water balance:

I. An impairment affecting the synthesis or release of ADH results in a diminished ability of the kidney to conserve water.
II. This impairment leads to water loss and dehydration, a condition known as Diabetes Insipidus.
III. Diabetes Insipidus is associated with the loss of glucose through urine and the formation of harmful ketone bodies.

Which of the statements given above are correct?

Consider the following statements about the pineal gland and melatonin:

I. The pineal gland is located on the ventral side of the forebrain.
II. Melatonin plays a very important role in regulating the 24-hour (diurnal) rhythm of the body.
III. Melatonin helps maintain the normal sleep-wake cycle and body temperature.
IV. Melatonin has no influence on metabolism, pigmentation, or menstrual cycles.

Which of the statements given above are incorrect?

Read the statements below regarding the thyroid gland's structure:

I. The thyroid gland consists of two lobes located on either side of the trachea.
II. Both lobes are interconnected with a thin flap of connective tissue called the isthmus.
III. The thyroid gland is composed of follicles and stromal tissues.
IV. The thyroid follicular cells synthesise three hormones: T₃, T₄, and thyrocalcitonin (TCT).

Select the correct statements.

Read the statements regarding thyroid deficiencies and pregnancy:

I. Deficiency of iodine in our diet results in hyperthyroidism and enlargement of the thyroid gland (goitre).
II. Hypothyroidism during pregnancy causes defective development and maturation of the growing baby, leading to cretinism (stunted growth).
III. Cretinism is characterized by mental retardation, low intelligence quotient, abnormal skin, and deaf-mutism.
IV. In adult women, hypothyroidism may cause the menstrual cycle to become highly regular and shortened.

Identify the correct statement combination.

Consider the statements regarding hyperthyroidism and Graves' disease:

I. Due to cancer of the thyroid gland or the development of nodules, the rate of synthesis of thyroid hormones increases to abnormal levels.
II. Exophthalmic goitre (Graves' disease) is a form of hypothyroidism.
III. Graves' disease is characterized by enlargement of the thyroid gland, protrusion of eyeballs, increased basal metabolic rate, and weight loss.
IV. Thyroid hormones play an important role in the regulation of the basal metabolic rate.

Which of the statements given above are correct?

Analyze the functions of thyroid hormones and related secretions:

I. Thyroid hormones support the process of red blood cell (RBC) formation.
II. Thyroid hormones control the metabolism of carbohydrates, proteins, and fats.
III. Maintenance of water and electrolyte balance is influenced by thyroid hormones.
IV. Thyrocalcitonin (TCT) is a protein hormone that increases the blood calcium levels.

Choose the incorrect statement(s) from the following.

Read the statements regarding the parathyroid glands:

I. In humans, four parathyroid glands are present on the back side of the thyroid gland, one pair each in the two lobes.
II. The parathyroid glands secrete a peptide hormone called parathyroid hormone (PTH) which is regulated by circulating sodium levels.
III. PTH increases Ca²⁺ levels in the blood by acting on bones and stimulating bone resorption.
IV. PTH is a hypocalcemic hormone that reduces calcium levels.

Which of the statements given above are correct?

Consider the following statements about calcium homeostasis mechanisms:

I. PTH stimulates the reabsorption of Ca²⁺ by the renal tubules.
II. PTH increases Ca²⁺ absorption from the digested food.
III. Along with TCT, PTH plays a significant role in calcium balance in the body.
IV. Both PTH and TCT are hypercalcemic hormones.

Identify the combination of correct statements.

Read the following statements regarding the thymus gland and immunity:

I. The thymus gland is a lobular structure located between the lungs behind the sternum on the ventral side of the aorta.
II. Thymosins play a major role in the differentiation of B-lymphocytes, which provide cell-mediated immunity.
III. Thymosins promote the production of antibodies to provide humoral immunity.
IV. The thymus gland degenerates in old individuals, resulting in decreased thymosin production and weakened immune responses.

Choose the correct statement(s).