Nokea
Which structure in the ear is responsible for hearing?
- A. Cochlea
- B. Semicircular canals
- C. Ossicles
- D. Eustachian tube
Correct Answer: A
Rationale: The cochlea, located in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are sent to the brain for processing. It plays a crucial role in the process of hearing by translating mechanical vibrations into electrical signals that the brain can interpret as sound. The semicircular canals (Choice B) are responsible for balance and detecting head movements, not hearing. The ossicles (Choice C) are three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the cochlea. The Eustachian tube (Choice D) helps equalize pressure between the middle ear and the atmosphere, but it is not directly involved in the process of hearing.
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What is the main function of the immune system?
- A. To produce hormones
- B. To protect the body from infections
- C. To remove waste products
- D. To regulate body temperature
Correct Answer: B
Rationale: The main function of the immune system is to protect the body from infections by identifying and destroying pathogens like bacteria and viruses. It plays a crucial role in maintaining overall health and preventing illnesses. Choice A is incorrect because hormone production is primarily handled by the endocrine system, not the immune system. Choice C is incorrect as waste removal is mainly performed by the excretory system, not the immune system. Choice D is incorrect as regulating body temperature is primarily the role of the thermoregulatory system, not the immune system.
Which structure in the kidney filters blood to form urine?
- A. Nephron
- B. Glomerulus
- C. Bowman's capsule
- D. Loop of Henle
Correct Answer: B
Rationale: The glomerulus is a key structure in the kidney responsible for filtering blood. It consists of a network of capillaries that filter waste products and excess substances from the blood, allowing the formation of urine. While the nephron, Bowman's capsule, and Loop of Henle are also essential components of the kidney's filtration system, the glomerulus is specifically involved in the initial blood filtration process. The nephron is the functional unit of the kidney, Bowman's capsule surrounds the glomerulus and collects the filtrate, and the Loop of Henle is responsible for reabsorption and concentration of urine, not the initial blood filtration.
What is the most visible part of the ear?
- A. Ear canal
- B. Cochlea
- C. Organ of Corti
- D. Pinna
Correct Answer: D
Rationale: The pinna, also known as the auricle, is the most visible part of the ear. Its external shape and location make it easily noticeable on the side of the head. The pinna helps in capturing sound waves and directing them into the ear canal, where the sound transmission process begins. The other structures listed, the Organ of Corti, Cochlea, and Ear canal, are essential parts of the ear involved in hearing and sound processing, but they are not as visibly prominent as the pinna. Therefore, the correct answer is the pinna because of its external visibility and role in capturing sound waves.
Which of the following is not part of the central nervous system?
- A. Retina
- B. Spinal cord
- C. Brain
- D. Heart
Correct Answer: B
Rationale: The central nervous system consists of the brain and spinal cord, which are responsible for processing and coordinating information. The retina is part of the eye, while the heart is part of the circulatory system. Therefore, the correct answer is 'Spinal cord' as it is not part of the central nervous system.
Which hormone is released by the adrenal glands during stress?
- A. Insulin
- B. Adrenaline
- C. Melatonin
- D. Cortisol
Correct Answer: B
Rationale: Adrenaline, also known as epinephrine, is released by the adrenal glands during stress to prepare the body for rapid action. It helps in triggering the body's fight-or-flight response, increasing heart rate, and providing a burst of energy when faced with stressful situations. Insulin (Choice A) is produced by the pancreas to regulate blood sugar levels, not by the adrenal glands. Melatonin (Choice C) is a hormone that regulates sleep-wake cycles and is produced by the pineal gland, not the adrenal glands. Cortisol (Choice D) is another hormone produced by the adrenal glands, but it is not the primary hormone released during immediate stress responses; it is more involved in long-term stress regulation.