Atrial natriuretic hormone (ANH) is produced by cells of the ___.

Correct Answer: B

Rationale: The correct answer is B: right atrium of the heart. Atrial natriuretic hormone (ANH) is produced by specialized cells in the right atrium of the heart called atrial myocytes. When the heart senses an increase in blood volume or pressure, these cells release ANH to help regulate fluid and electrolyte balance by promoting sodium and water excretion by the kidneys. Choices A, C, and D are incorrect because ANH is not produced by the kidney tubules, adrenal cortex, or pancreas. The primary site of ANH production is specifically within the cardiac atria.

Correct Answer: C

Rationale: The correct answer is C: Myxedema. Insufficient levels of thyroid hormone in adults lead to myxedema due to decreased metabolism and energy production. Goiter (A) is the enlargement of the thyroid gland, not caused by low thyroid hormone levels. Tetany (B) is muscle spasms due to low calcium levels, not related to thyroid hormone deficiency. Cretinism (D) is a condition of severe hypothyroidism in infants, not in adults. Therefore, the correct choice is C as it directly relates to the consequences of low thyroid hormone levels in adults.

Correct Answer: C

Rationale: The correct answer is C: Oestrogen. Oestrogen is the primary female sex hormone responsible for the development of secondary sexual characteristics such as breast development, regulation of the menstrual cycle, and maintenance of the reproductive system. Adrenaline (A) is a stress hormone that prepares the body for fight or flight responses. Glucagon (B) is a hormone that raises blood sugar levels. Calcitonin (D) is involved in regulating calcium levels in the body. These hormones do not play a direct role in the development of female secondary sexual characteristics.

Correct Answer: B

Rationale: The correct answer is B: increased gastric motility and emptying. Cholecystokinin (CCK) is a hormone that primarily functions to stimulate gallbladder contraction (A), secretion of pancreatic juice (D), and inhibit gastric motility and emptying. Choice C, glucagon secretion, is not directly related to the actions of CCK. The incorrect choices (A, C, D) are all actions associated with CCK, while choice B goes against the typical action of CCK on gastric motility.

Correct Answer: A

Rationale: The correct answer is A: short chain fatty acids. Short chain fatty acids are primarily absorbed in the colon through passive diffusion. The colon plays a crucial role in absorbing these fatty acids due to its high concentration of beneficial gut bacteria that break down dietary fiber into short chain fatty acids. Calcium is mainly absorbed in the small intestine, vitamin K is absorbed in the small intestine and partially in the colon, and oligosaccharides are mainly broken down by enzymes in the small intestine.