Nokea
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.
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What is the primary function of the nervous system?
- A. To transmit signals and coordinate body activities
- B. To fight infections
- C. To produce hormones
- D. To regulate body temperature
Correct Answer: A
Rationale: The primary function of the nervous system is to transmit signals and coordinate body activities. It controls and regulates body functions by sending and receiving signals between different parts of the body, enabling responses to internal and external stimuli. This intricate network allows for communication between the brain, spinal cord, and the rest of the body, ultimately facilitating movement, sensation, thoughts, and various bodily functions. Choices B, C, and D are incorrect as they do not represent the primary function of the nervous system. Fighting infections is primarily the role of the immune system, producing hormones is the function of the endocrine system, and regulating body temperature involves mechanisms of thermoregulation within the body, not directly controlled by the nervous system.
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 main function of the endocrine system?
- A. To fight infections
- B. To regulate body functions through hormones
- C. To produce red blood cells
- D. To transport oxygen
Correct Answer: B
Rationale: The main function of the endocrine system is to regulate various body functions by releasing hormones, which act as chemical messengers. These hormones help maintain homeostasis, regulate metabolism, growth, development, and other essential functions in the body. Option A is incorrect as fighting infections is primarily the role of the immune system, not the endocrine system. Option C is incorrect as the production of red blood cells mainly occurs in the bone marrow. Option D is incorrect as the transportation of oxygen is primarily carried out by the respiratory and circulatory systems. Therefore, option B is the correct answer as it accurately describes the primary role of the endocrine system.
Which of the following is a structure found in the upper respiratory tract?
- A. Larynx
- B. Pharynx
- C. Esophagus
- D. Trachea
Correct Answer: B
Rationale: The pharynx is indeed a structure located in the upper respiratory tract. It acts as a common passageway for both air heading to the lungs and food traveling to the esophagus, making it a vital structure for breathing and swallowing functions. The larynx, trachea, and esophagus are also part of the respiratory and digestive systems but are not specifically located in the upper respiratory tract. The larynx is situated below the pharynx, while the trachea is found below the larynx, and the esophagus is part of the digestive system, not the respiratory tract.
What is the function of the small intestine?
- A. To store bile
- B. To absorb nutrients
- C. To digest food
- D. To produce enzymes
Correct Answer: B
Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It is responsible for absorbing nutrients from the digested food into the bloodstream for distribution throughout the body. Therefore, the correct function of the small intestine is to absorb nutrients. Choice A is incorrect because the gallbladder stores bile, not the small intestine. Choice C is incorrect because the digestion process primarily occurs in the stomach and small intestine. Choice D is incorrect because while the small intestine does play a role in enzyme production, its primary function is nutrient absorption.