What is the primary function of the cardiovascular system?
- A. To transport oxygen and nutrients
- B. To remove waste products
- C. To regulate body temperature
- D. To fight infections
Correct Answer: A
Rationale: The correct answer is A: "To transport oxygen and nutrients." The primary function of the cardiovascular system is to transport oxygen, nutrients, and hormones to cells throughout the body and remove waste products. This system plays a crucial role in maintaining homeostasis by delivering essential substances to tissues and organs while eliminating metabolic waste. Choices B, C, and D are incorrect because although the cardiovascular system indirectly helps in removing waste products through circulation, its primary function is focused on transporting essential substances and not on regulating body temperature or fighting infections.
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Which gland produces the hormone melatonin?
- A. Pineal gland
- B. Thyroid gland
- C. Pituitary gland
- D. Adrenal gland
Correct Answer: A
Rationale: The correct answer is the Pineal gland. The pineal gland is responsible for producing melatonin, a hormone that helps regulate the sleep-wake cycle. Melatonin secretion is influenced by light exposure. Higher levels are observed at night to promote sleep, while lower levels during the day encourage wakefulness. Choices B, C, and D are incorrect as they are not associated with the production of melatonin. The thyroid gland produces hormones like thyroxine and triiodothyronine, the pituitary gland controls various other glands, and the adrenal gland produces hormones like adrenaline and cortisol.
What is the role of the alveoli in the lungs?
- A. To filter blood
- B. To exchange gases
- C. To transport nutrients
- D. To store oxygen
Correct Answer: B
Rationale: The alveoli in the lungs are tiny air sacs responsible for the exchange of oxygen and carbon dioxide during breathing. Oxygen from inhaled air diffuses into the bloodstream through the alveoli, while carbon dioxide produced by cells is removed from the blood and exhaled out of the body through the alveoli. This gas exchange process is essential for the body to obtain oxygen and get rid of carbon dioxide, supporting cellular functions and maintaining overall health. Choices A, C, and D are incorrect because the alveoli do not filter blood, transport nutrients, or store oxygen. Their main function is gas exchange.
What is the role of the pancreas in digestion?
- A. To secrete digestive enzymes
- B. To store bile
- C. To absorb nutrients
- D. To transport glucose
Correct Answer: A
Rationale: The correct answer is A: To secrete digestive enzymes. The pancreas is responsible for secreting digestive enzymes that aid in breaking down carbohydrates, fats, and proteins in the small intestine, facilitating the process of digestion. Choice B is incorrect because the pancreas does not store bile; that is primarily the function of the gallbladder. Choice C is incorrect as the absorption of nutrients mainly occurs in the small intestine, not the pancreas. Choice D is incorrect as the transport of glucose is primarily regulated by insulin produced in the pancreas, but this is not the main role of the pancreas in digestion.
Nerve tissue is composed of neurons and connective tissue cells that are referred to as which of the following?
- A. Osteoblasts
- B. Neuroglia
- C. Osteocytes
- D. Arterioles
Correct Answer: B
Rationale: Neuroglia are specialized connective tissue cells that provide support and protection to neurons in the nervous system. They assist in the proper functioning of neurons and are essential for maintaining the overall health of nerve tissue. Therefore, in the context of nerve tissue composition, neuroglia are the connective tissue cells associated with neurons. The other choices, osteoblasts, osteocytes, and arterioles, are not the correct types of connective tissue cells found in nerve tissue. Osteoblasts are involved in bone formation, osteocytes are mature bone cells, and arterioles are small blood vessels that supply blood to tissues.
Which structure in the kidney is responsible for filtering blood?
- A. Glomerulus
- B. Bowman's capsule
- C. Loop of Henle
- D. Collecting duct
Correct Answer: A
Rationale: The glomerulus is the correct answer. It is a vital structure in the kidney responsible for filtering blood. The glomerulus is a network of capillaries that filters waste products and excess substances from the blood to form urine. While the Bowman's capsule, Loop of Henle, and Collecting duct are also essential components of the nephron, the primary site of blood filtration occurs at the glomerulus. The Bowman's capsule surrounds the glomerulus and collects the filtered fluid, the Loop of Henle reabsorbs water and important ions, and the Collecting duct further concentrates the urine, but none of these structures are primarily responsible for filtering blood as the glomerulus is.