What is the function of the pancreas in digestion?

Correct Answer: A

Rationale: The correct answer is A: Secreting digestive enzymes. The pancreas aids in digestion by secreting digestive enzymes that are essential for breaking down carbohydrates, fats, and proteins in the small intestine. These enzymes help in the absorption of nutrients from food, facilitating the digestive process. Choices B, C, and D are incorrect. The pancreas does not produce bile (choice B), store glucose (choice C), or primarily regulate blood sugar levels (choice D) in the context of digestion.

Correct Answer: A

Rationale: The pinna, also known as the auricle, is the external part of the ear that is most visible. It helps in collecting sound waves and directing them into the ear canal for further processing by the ear structures. The pinna's visible location makes it easily identifiable as the prominent external feature of the ear. Choices B, C, and D are incorrect. The Organ of Corti is located within the cochlea and is responsible for converting sound vibrations into electrical signals. The cochlea is a spiral-shaped, fluid-filled structure in the inner ear that plays a crucial role in hearing. The ear canal is a passage that leads to the eardrum and is not the most visible part of the ear.

Correct Answer: B

Rationale: Vitamin C is essential for the synthesis of collagen, a crucial protein that plays a significant role in maintaining the structural integrity of skin, blood vessels, and bones. Collagen is responsible for the strength, elasticity, and firmness of these tissues. Without sufficient vitamin C, the body cannot form collagen properly, leading to various health issues like scurvy, impaired wound healing, and fragile blood vessels. Choices A, C, and D are incorrect. Vitamin A plays a role in vision, immune function, and skin health. Vitamin D is crucial for bone health and immune function, while Vitamin E is an antioxidant that helps protect cells from damage.

Correct Answer: B

Rationale: The correct answer is B, Cortisol. Cortisol is the hormone produced by the adrenal cortex. It plays a crucial role in regulating metabolism, immune response, and managing stress. Insulin is produced by the pancreas, thyroxine by the thyroid gland, and glucagon by the pancreas. Therefore, choices A, C, and D are incorrect as they are not hormones produced by the adrenal cortex.

Correct Answer: B

Rationale: The cell membrane, also known as the plasma membrane, is responsible for regulating the transport of substances in and out of the cell. It acts as a selective barrier, allowing the passage of certain molecules while restricting others. This selective permeability helps maintain homeostasis within the cell by controlling the movement of essential substances like nutrients and waste products. The nucleus (Choice A) is the organelle that houses the cell's genetic material and is not directly involved in regulating substance transport. Cytoplasm (Choice C) is the gel-like substance that fills the cell and does not play a direct role in regulating substance transport. Mitochondria (Choice D) are responsible for energy production in the cell through cellular respiration and are not primarily involved in substance transport.

Correct Answer: B

Rationale: Thyroxine is the hormone produced by the thyroid gland. It plays a crucial role in regulating metabolism, heart rate, and growth. Insulin is produced by the pancreas to regulate blood sugar levels, not by the thyroid gland. Glucagon is also produced by the pancreas and helps increase blood sugar levels. Cortisol is produced by the adrenal glands and is involved in stress response and metabolism, not by the thyroid gland.

Correct Answer: A

Rationale: The primary function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the air and the bloodstream. Oxygen is taken in during inhalation and transported to cells, while carbon dioxide is removed during exhalation as a waste product of cellular metabolism. Choices B, C, and D are incorrect as they do not reflect the primary function of the respiratory system. Regulating body temperature is mainly controlled by the thermoregulatory system, fighting infections is a function of the immune system, and producing energy is primarily done by the metabolic system.

Correct Answer: A

Rationale: Melatonin, produced by the pineal gland, regulates the sleep-wake cycle by responding to light and darkness in the environment. It plays a crucial role in signaling the body when it's time to sleep and wake up, helping to establish and maintain a healthy circadian rhythm. Thyroxine, Insulin, and Cortisol do not directly regulate the sleep-wake cycle, making them incorrect choices for this question.

Correct Answer: C

Rationale: The thyroid gland is responsible for regulating metabolism. It produces hormones such as thyroxine, which plays a key role in influencing the body's metabolic rate. The pituitary gland is known as the 'master gland' but is not directly responsible for regulating metabolism. The adrenal gland is involved in the stress response and producing hormones like cortisol, not primarily regulating metabolism. The pineal gland produces melatonin, which regulates sleep-wake cycles, not metabolism. Therefore, the correct answer is the thyroid gland.