Which hormone is produced by the pancreas?

Correct Answer: A

Rationale: Insulin is the correct answer. Insulin is produced by the pancreas and plays a crucial role in regulating blood glucose levels. It facilitates the uptake of glucose into cells, helping to lower blood sugar levels. Glucagon, on the other hand, is also produced by the pancreas but functions to raise blood glucose levels by stimulating the release of glucose from the liver. Somatostatin is another hormone produced by the pancreas that helps regulate the endocrine system. Cortisol, produced by the adrenal glands, plays a role in stress response and metabolism, not by the pancreas.

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. A pivot joint, like the one found in the neck, allows for rotational movement, enabling the head to turn from side to side. Hinge joints (Choice A) allow movement in one plane like a door hinge and are not found in the neck. Ball and socket joints (Choice C) allow for a wide range of motion in multiple directions and are typically found in the hip and shoulder. Saddle joints (Choice D) allow for movement back and forth and side to side, like the thumb joint, but are not found in the neck.

Correct Answer: A

Rationale: Melatonin, produced by the pineal gland, is the hormone that regulates the sleep-wake cycle. Its secretion is influenced by light exposure, with levels typically rising in the evening to promote sleep and falling in the morning to encourage wakefulness. Insulin is involved in regulating blood sugar levels, not the sleep-wake cycle. Cortisol plays a role in the body's stress response and circadian rhythm but is not the primary hormone regulating sleep-wake cycles. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism, not the sleep-wake cycle.

Correct Answer: A

Rationale: Hemoglobin, located in red blood cells, is responsible for binding to oxygen in the lungs and transporting it to tissues throughout the body. Red blood cells contain hemoglobin, making them the primary carrier of oxygen to cells. Hemoglobin is the correct answer because it is the protein within red blood cells that directly binds to oxygen for transport. Plasma is the liquid component of blood and does not carry oxygen. Platelets are responsible for blood clotting and have no role in oxygen transport. While red blood cells do carry oxygen, it is specifically the hemoglobin within them that performs this function.

Correct Answer: C

Rationale: The amygdala, located in the temporal lobe of the brain, is responsible for regulating emotions and memory, particularly those related to fear and pleasure. It plays a crucial role in processing emotional responses, forming emotional memories, and modulating emotional reactions. The cerebrum (Choice A) is responsible for higher brain functions such as thought and action. The cerebellum (Choice B) is mainly involved in coordination and balance. The brainstem (Choice D) controls basic life functions such as breathing and heart rate.

Correct Answer: A

Rationale: The correct answer is the Adrenal gland. The adrenal glands are located on top of the kidneys. They produce hormones such as adrenaline and cortisol, which play essential roles in regulating metabolism, immune response, and stress in the body. The Thyroid gland, Pineal gland, and Pancreas are not located on top of the kidneys. The Thyroid gland is located in the neck, the Pineal gland in the brain, and the Pancreas behind the stomach.

Correct Answer: A

Rationale: The parathyroid gland is not involved in the release of hormones during stress. It is responsible for regulating calcium levels in the blood by secreting parathyroid hormone. During stress, the adrenal cortex, posterior pituitary, and hypothalamus play crucial roles in releasing stress hormones like cortisol, adrenaline, and oxytocin. Therefore, the correct answer is the parathyroid gland, as it is not directly associated with the release of stress-related hormones.

Correct Answer: B

Rationale: White blood cells are a vital part of the immune system. Their primary function is to fight infections by attacking bacteria, viruses, and other pathogens that enter the body. They play a crucial role in protecting the body against illnesses and maintaining overall health. Choice A is incorrect because the role of carrying oxygen to cells is primarily performed by red blood cells. Choice C is incorrect as the transportation of nutrients is mainly carried out by the bloodstream and specialized cells. Choice D is incorrect as the process of clotting blood is primarily mediated by platelets.

Correct Answer: C

Rationale: Veins are the blood vessels that carry deoxygenated blood back to the heart, except for the pulmonary veins which carry oxygenated blood from the lungs. Arteries carry oxygenated blood away from the heart. Capillaries facilitate the exchange of nutrients and gases between the blood and tissues but do not specifically carry blood back to the heart. Lymphatic vessels are part of the lymphatic system responsible for immune function and do not directly carry blood back to the heart. Therefore, the correct answer is veins.