The normal endocrine controls can be directly overridden by the __________ system.

Correct Answer: A

Rationale: The correct answer is A: nervous system. The nervous system can directly override normal endocrine controls through the release of neurotransmitters that can stimulate or inhibit hormone release from endocrine glands. The nervous system can rapidly respond to immediate changes in the internal or external environment, allowing for quick adjustments in hormone levels. Summary of why the other choices are incorrect: B: The circulatory system is not involved in directly overriding endocrine controls. C: The digestive system primarily regulates the breakdown and absorption of nutrients, not endocrine controls. D: The reproductive system is responsible for the production of sex hormones and gametes, but it does not directly override normal endocrine controls.

Correct Answer: C

Rationale: The correct answer is C: Splenic artery. The splenic artery supplies the tail of the pancreas through its branches. The splenic artery runs along the superior border of the pancreas and gives off multiple branches that supply various parts of the pancreas, including the tail. A: Inferior pancreaticoduodenal artery supplies the inferior part of the pancreas. B: Left gastroepiploic artery supplies the greater curvature of the stomach. D: Superior pancreaticoduodenal artery supplies the pancreatic head and duodenum. Therefore, the splenic artery is the correct answer as it specifically supplies the tail of the pancreas.

Correct Answer: D

Rationale: The correct answer is D because insulin and glucagon are both hormones secreted by the pancreas to regulate blood glucose levels. Insulin is secreted by beta cells in response to high blood glucose levels, promoting glucose uptake by cells. Glucagon is secreted by alpha cells in response to low blood glucose levels, stimulating the release of stored glucose. Choices A and C are incorrect because insulin is secreted by beta cells, not glucagon, and they are secreted in response to high, not low, glucose levels. Choice B is incorrect because insulin lowers blood glucose levels, while glucagon raises them.

Correct Answer: A

Rationale: The correct answer is A: Adrenal cortex. The adrenal cortex is associated with producing hormones related to sugar (glucocorticoids), salt (mineralocorticoids), and sex (androgens). Glucocorticoids regulate glucose metabolism, mineralocorticoids regulate salt balance, and androgens are sex hormones. The pancreas primarily regulates blood sugar levels. The parathyroid gland is responsible for calcium and phosphorus balance, not sugar, salt, and sex. The neurohypophysis is part of the pituitary gland and mainly regulates water balance and blood pressure, not specifically sugar, salt, and sex.

Correct Answer: B

Rationale: The correct answer is B: Releasing hormones. Releasing hormones are produced in the hypothalamus and travel through the hypophyseal-hypothalamic portal capillaries to reach the anterior pituitary gland. This is where they stimulate the release of specific hormones. Gonadotropins (A) are produced by the anterior pituitary gland, not found within the portal capillaries. Catecholamines (C) are produced by the adrenal glands, not within the portal capillaries. Mineralocorticoids (D) are steroid hormones produced by the adrenal cortex, not found within the portal capillaries.