Anti-diuretic hormone secretion is:

Correct Answer: B

Rationale: Anti-diuretic hormone (ADH), also known as vasopressin, is a hormone released by the pituitary gland in response to changes in blood osmolality, blood volume, and blood pressure. During hemorrhage (significant blood loss), the body experiences a decrease in blood volume and blood pressure. In response to this decrease in blood volume, ADH secretion is increased to help the body retain water and maintain blood pressure levels. Therefore, it is incorrect to say that ADH secretion is reduced during hemorrhage.

Correct Answer: A

Rationale: Thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), play a crucial role in regulating metabolism in the body. They are responsible for increasing the metabolic rate of cells by influencing the production of proteins and controlling how the body uses energy. This increase in metabolic rate results in processes such as increased heart rate, enhanced nutrient breakdown, and higher body temperature. Thus, option A, "increase metabolic rate," is the correct statement regarding thyroid hormones (T3 and T4).

Correct Answer: D

Rationale: Aldosterone is a hormone produced in the zona glomerulosa of the adrenal cortex, not the zona fasciculata (Choice A is incorrect). Conn's syndrome, also known as primary hyperaldosteronism, is characterized by excess aldosterone secretion, not a deficiency (Choice B is incorrect). Aldosterone production is under the control of the renin-angiotensin-aldosterone system, which is stimulated by factors such as low blood pressure, low blood volume, and high potassium levels. Elevated potassium in the blood directly suppresses aldosterone production by the adrenal glands, serving as a negative feedback mechanism to maintain electrolyte balance (Choice D is correct). The synthesis of aldosterone also requires cholesterol as the precursor, rather than pregnenolone (Choice E is incorrect). Lastly, aldosterone production is regulated in part by ACTH (adrenocorticotropic hormone), as it can enhance the effects of

Correct Answer: D

Rationale: Parathyroid hormone (PTH) is a hormone produced by the parathyroid glands in response to low blood calcium levels. Its main function is to raise calcium levels in the blood by acting on the bones, kidneys, and intestines. PTH stimulates the release of calcium from the bones, enhances the absorption of calcium by the intestines, and promotes the reabsorption of calcium by the kidneys. Therefore, it is secreted in increased amounts when blood calcium levels are below normal in order to maintain overall calcium balance in the body.

Correct Answer: B

Rationale: Diabetes Insipidus is a condition characterized by the body's inability to properly regulate water balance, leading to excessive urination and extreme thirst. This disorder is caused by a deficiency of vasopressin, also known as antidiuretic hormone (ADH). Vasopressin is a hormone produced by the hypothalamus and released by the pituitary gland to help regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. The lack of vasopressin in Diabetes Insipidus results in the kidneys producing a large volume of dilute urine, leading to dehydration and electrolyte imbalances.