Which of the following hormones is responsible for regulating metabolism?

Correct Answer: B

Rationale: Thyroxine, produced by the thyroid gland, is the hormone responsible for regulating metabolism. It plays a fundamental role in controlling the body's metabolic rate, affecting processes such as energy production and utilization. Thyroxine also influences growth and development in the body. Choice A, Insulin, is involved in regulating blood sugar levels and promoting the storage of glucose. While insulin has an impact on metabolism, it is not primarily responsible for regulating overall metabolic rate. Choice C, Glucagon, acts in opposition to insulin, stimulating the release of glucose from the liver to increase blood sugar levels. Glucagon primarily targets glucose regulation rather than overall metabolism. Choice D, Cortisol, is known as the stress hormone and plays a role in the body's response to stress, regulation of blood pressure, immune function, and anti-inflammatory actions. While cortisol can have some effects on metabolism during stress responses, it is not the primary hormone responsible for regulating overall metabolic rate.

Correct Answer: B

Rationale: The correct answer is B: 'To produce bile and detoxify substances.' The liver's primary functions include producing bile, which aids in the digestion and absorption of fats, and detoxifying harmful substances in the blood. While the liver does play a role in blood filtration, its key functions are related to bile production and detoxification. Choices C and D are incorrect because the liver does not produce insulin (produced by the pancreas) or red blood cells (produced in the bone marrow).

Correct Answer: B

Rationale: Tendons are the correct answer. They are strong connective tissues that connect muscles to bones, allowing movement when muscles contract. Ligaments connect bones to other bones, providing joint stability. Cartilage is a firm, flexible connective tissue present in joints and the outer ear. Fascia is a connective tissue that surrounds muscles, blood vessels, and nerves, offering support and protection. Therefore, the correct tissue type that connects muscles to bones is tendons.

Correct Answer: B

Rationale: The correct answer is B: To produce bile. The liver's primary function in the digestive system is to produce bile. Bile is essential for the digestion and absorption of fats in the small intestine. It helps emulsify fats, making it easier for enzymes to break them down into smaller molecules for absorption. Choices A, C, and D are incorrect as storing glucose is primarily done in the liver for energy maintenance, detoxifying harmful substances is a function of the liver related to metabolism but not specifically in the digestive system, and absorbing nutrients is mainly done in the small intestine rather than the liver.

Correct Answer: B

Rationale: The gallbladder's main function is to store and concentrate bile produced by the liver. Bile is essential for the digestion and absorption of fats in the small intestine. Therefore, the correct answer is B, as the gallbladder acts as a reservoir for bile rather than producing it. Choices A, C, and D are incorrect because the gallbladder does not produce bile, detoxify harmful substances, or regulate blood sugar in the digestive system.

Correct Answer: B

Rationale: The pinna, also known as the auricle, is the most visible part of the ear. It is responsible for capturing sound waves and directing them into the ear canal, where the process of hearing begins. The other structures mentioned, such as the cochlea, ear canal, and organ of Corti, play crucial roles in the auditory system but are not the most visible parts of the ear. The cochlea is a spiral-shaped cavity responsible for converting sound vibrations into neural signals. The ear canal is a tube that connects the outer ear to the eardrum. The organ of Corti is the actual sensory organ of hearing located in the cochlea.

Correct Answer: B

Rationale: The correct answer is the amygdala. It is a small, almond-shaped structure located within the temporal lobe of the brain. The amygdala plays a crucial role in processing emotions such as fear, anger, pleasure, and other emotional responses. It is involved in the formation of emotional memories and helps regulate emotional responses to various stimuli. The frontal lobe is mainly responsible for higher cognitive functions such as decision-making and problem-solving, not processing emotions. The parietal lobe is involved in processing sensory information and spatial awareness, while the occipital lobe is primarily responsible for processing visual information.

Correct Answer: B

Rationale: Parathyroid hormone, produced by the parathyroid glands, is responsible for regulating calcium levels in the blood. It achieves this by increasing calcium absorption in the intestines and kidneys, thus maintaining appropriate calcium levels in the bloodstream. Insulin is involved in glucose metabolism, not calcium regulation. Cortisol is a stress hormone that affects various body functions but not calcium levels. Melatonin is responsible for regulating the sleep-wake cycle, not calcium levels.

Correct Answer: B

Rationale: Cartilage is the correct answer as it is the substance that makes up the pads between the vertebrae. Cartilage provides cushioning and support between the bones of the spine, allowing for flexibility and preventing friction between the vertebrae. Bone (choice A) is incorrect as it forms the structure of the vertebrae, not the intervertebral discs. Tendon (choice C) is incorrect as it connects muscle to bone and is not found between the vertebrae. Fat (choice D) is incorrect as it is not the substance that makes up the pads between the vertebrae.