Which of the following is an organ of the respiratory system?
- A. Brain
- B. Larynx
- C. Urethra
- D. Pancreas
Correct Answer: B
Rationale: The larynx is an essential organ of the respiratory system. It plays a crucial role in producing sound, protecting the trachea from food aspiration, and regulating the airflow to and from the lungs. The brain is part of the nervous system, the urethra is part of the urinary system, and the pancreas is part of the digestive system. Therefore, they are not directly related to the respiratory system's functions.
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What is the role of enzymes in the body?
- A. To produce energy
- B. To speed up chemical reactions
- C. To transport molecules
- D. To repair tissues
Correct Answer: B
Rationale: Enzymes are biological catalysts that facilitate and speed up chemical reactions in the body. They do not produce energy but enable various processes such as digestion and metabolism by lowering the activation energy required for reactions to occur. Choice A is incorrect because enzymes do not produce energy themselves but assist in energy production through reactions. Choice C is incorrect as enzymes do not primarily function in transporting molecules, although some may have a role in specific transport processes. Choice D is incorrect as the primary role of enzymes is not to repair tissues, but rather to catalyze biochemical reactions.
What is the function of the gallbladder?
- A. To produce bile
- B. To store and concentrate bile
- C. To detoxify harmful substances
- D. To break down fats
Correct Answer: B
Rationale: The correct answer is B: To store and concentrate bile. The gallbladder's primary function is to store and concentrate bile, which is produced by the liver. Bile is released into the small intestine to aid in the digestion and absorption of fats. It helps in emulsifying fats and facilitating their breakdown by enzymes for better absorption. Choices A, C, and D are incorrect because the gallbladder does not produce bile (it is produced by the liver), detoxify harmful substances, or directly break down fats. Its main role is to store and concentrate bile before releasing it into the small intestine.
What is the role of the stomach in digestion?
- A. To absorb nutrients
- B. To break down food
- C. To secrete digestive enzymes
- D. To transport nutrients
Correct Answer: B
Rationale: The correct answer is B: To break down food. The stomach's primary function in digestion is to mechanically and chemically break down food. It achieves this by utilizing gastric acid and digestive enzymes to convert food into chyme, a semi-liquid mixture. The chyme is then passed to the small intestine for further processing and absorption of nutrients. Choices A, C, and D are incorrect because the stomach's main role is not to absorb nutrients, secrete digestive enzymes, or transport nutrients; instead, it primarily focuses on breaking down food.
Which structure in the ear is responsible for balance?
- A. Cochlea
- B. Semicircular canals
- C. Ossicles
- D. Eustachian tube
Correct Answer: B
Rationale: The semicircular canals in the inner ear are responsible for maintaining balance by detecting changes in head position and movement. These structures contain fluid and hair cells that send signals to the brain regarding the body's orientation in space, helping us stay balanced and navigate our surroundings. The cochlea is responsible for hearing, the ossicles are involved in sound transmission, and the Eustachian tube helps equalize pressure in the middle ear, but they are not directly related to balance.
What is the function of hemoglobin in red blood cells?
- A. To fight infections
- B. To transport oxygen
- C. To carry carbon dioxide
- D. To store oxygen
Correct Answer: B
Rationale: The correct answer is B: 'To transport oxygen.' Hemoglobin in red blood cells plays a crucial role in transporting oxygen. It binds to oxygen in the lungs and carries it to the body's tissues and organs for cellular respiration. Choices A, C, and D are incorrect because hemoglobin's primary function is to bind and transport oxygen, not to fight infections, carry carbon dioxide, or store oxygen.