Nokea
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.
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What is the primary function of the respiratory system?
- A. To remove carbon dioxide from the body
- B. To transport oxygen to the cells
- C. To deliver nutrients to cells
- D. To create sound and speech
Correct Answer: B
Rationale: The primary function of the respiratory system is to facilitate the exchange of gases. It transports oxygen from the air into the bloodstream, which is crucial for cellular respiration and providing energy to the cells. Additionally, it removes carbon dioxide, which is a waste product that needs to be eliminated. Choices A, C, and D are incorrect because while the respiratory system does remove carbon dioxide, its primary role is oxygen transport, not nutrient delivery, sound, or speech production.
What is the primary role of hemoglobin in red blood cells?
- A. Carrying oxygen
- B. Carrying nutrients
- C. Carrying carbon dioxide
- D. Carrying waste products
Correct Answer: A
Rationale: The correct answer is A: Carrying oxygen. Hemoglobin's primary function in red blood cells is to bind with oxygen in the lungs and transport it to the body's tissues and cells. This process is crucial for cellular respiration and the overall oxygenation of the body. Choices B, C, and D are incorrect because hemoglobin primarily carries oxygen, not nutrients, carbon dioxide, or waste products.
What is the primary function of the digestive system?
- A. To transport oxygen
- B. To break down food and absorb nutrients
- C. To produce hormones
- D. To transport blood
Correct Answer: B
Rationale: The primary function of the digestive system is to break down food into smaller molecules and absorb nutrients such as vitamins, minerals, carbohydrates, proteins, and fats. These nutrients are then utilized by the body for energy, growth, and repair. The digestive system plays a crucial role in the process of extracting essential components from food and distributing them to the body's cells through the bloodstream. Choices A, C, and D are incorrect because transporting oxygen, producing hormones, and transporting blood are functions associated with other body systems like the respiratory system, endocrine system, and circulatory system, respectively, not the digestive system.
Which of the following is not a component of the central nervous system?
- A. Brain
- B. Heart
- C. Retina
- D. Spinal cord
Correct Answer: B
Rationale: The central nervous system comprises the brain and spinal cord, responsible for processing and transmitting information. The retina, though part of the eye, is an extension of the central nervous system. However, the heart is part of the circulatory system, responsible for pumping blood throughout the body. Therefore, the correct answer is the heart as it is not a component of the central nervous system.
Which of the following is a structure found in the upper respiratory tract?
- A. Pharynx
- B. Larynx
- C. Trachea
- D. Esophagus
Correct Answer: A
Rationale: The pharynx is a structure found in the upper respiratory tract. It serves as a common pathway for both air and food, playing a crucial role in directing air to the trachea and food to the esophagus. The larynx, trachea, and esophagus are important structures in the respiratory and digestive systems, but the pharynx specifically belongs to the upper respiratory tract, making it the correct answer.