The actions of gastrin include all but:

Correct Answer: A

Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric mucosal growth but not insulin secretion. Gastrin acts on parietal cells to stimulate acid production and chief cells to release pepsinogen. Choice B and C are incorrect as gastrin does have a trophic effect on colonic and gastric mucosa, respectively. Choice D is also incorrect as gastrin stimulates pepsin secretion.

Correct Answer: D

Rationale: Step 1: Activation of protein kinase A leads to phosphorylation of phosphorylase kinase. Step 2: Phosphorylase kinase phosphorylates and activates phosphorylase. Step 3: Active phosphorylase cleaves 1,4-glycosidic linkages in glycogen, not 1,6 linkages (eliminates A). Step 4: Phosphorylase is activated by phosphorylase kinase, not norepinephrine (eliminates B and C). Step 5: Inhibition of glycogen synthesis occurs when phosphorylase is activated, supporting choice D as the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Gonads. Gonads are the primary reproductive organs, responsible for producing sex hormones and gametes. In males, the testes produce testosterone and sperm, while in females, the ovaries produce estrogen and eggs. Adrenal glands (A) produce hormones like cortisol and adrenaline, which are not sex-specific. Parathyroid glands (C) regulate calcium levels in the body. Pancreas (D) produces insulin and digestive enzymes, unrelated to sex differences. Therefore, the secretion from gonads is the only one that differs between males and females due to their distinct reproductive functions.

Correct Answer: C

Rationale: The correct answer is C: TSH (Thyroid Stimulating Hormone). The anterior pituitary gland secretes TSH, which stimulates the thyroid gland to produce thyroid hormones. This is a key hormone involved in regulating metabolism. A: ADH (Antidiuretic Hormone) is produced by the posterior pituitary gland. B: Oxytocin is also produced by the posterior pituitary gland and is involved in uterine contractions and lactation. D: Cortisol is produced by the adrenal glands, not the pituitary gland. In summary, TSH is the correct answer as it is the only hormone listed that is produced by the anterior pituitary gland.

Correct Answer: B

Rationale: The correct answer is B: Oesophagus. After swallowing, the food bolus passes through the pharynx and enters the oesophagus, a muscular tube that connects the mouth to the stomach. The oesophagus helps transport the bolus to the stomach for further digestion. The pharynx is a common pathway for both food and air, but the food should not enter the trachea (D) as it leads to the lungs, causing choking. The stomach (C) is the final destination for the food bolus after passing through the oesophagus.