Nokea
Which of the following statements best describes endocrine glands?
- A. They secrete chemicals into the blood
- B. They secrete enzymes into ducts
- C. They produce sweat
- D. They produce saliva
Correct Answer: A
Rationale: Endocrine glands are ductless glands that release hormones directly into the bloodstream. These hormones are then carried to target organs and tissues throughout the body, where they regulate various physiological functions. The statement 'They secrete chemicals into the blood' accurately describes the function of endocrine glands. Choices B, C, and D are incorrect because endocrine glands do not secrete enzymes into ducts, produce sweat, or produce saliva. These functions are typically associated with exocrine glands, sweat glands, and salivary glands, respectively.
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What role does the liver play in metabolism?
- A. Storing glucose
- B. Secreting bile
- C. Detoxifying harmful substances
- D. Producing enzymes
Correct Answer: D
Rationale: The correct answer is D: Producing enzymes. The liver is involved in metabolism by producing enzymes that are essential for regulating various metabolic processes in the body. While the liver does store glucose, secrete bile, and detoxify harmful substances, its primary role in metabolism is producing enzymes that facilitate biochemical reactions necessary for energy production, nutrient breakdown, and waste elimination. Choices A, B, and C are incorrect because although the liver performs these functions, they are not directly related to its primary role in metabolism, which is producing enzymes.
What is the main function of white blood cells?
- A. To carry oxygen
- B. To fight infections
- C. To carry nutrients
- D. To remove waste products
Correct Answer: B
Rationale: The main function of white blood cells, also known as leukocytes, is to fight infections and foreign invaders to protect the body from harm. They play a crucial role in the immune system by identifying and destroying pathogens like bacteria and viruses, essential for maintaining the body's health and overall immunity. Choices A, C, and D are incorrect as carrying oxygen is primarily done by red blood cells, carrying nutrients is a function of various body systems, and removing waste products is mainly the role of the kidneys and liver, not white blood cells.
What is the primary function of the alveoli in the lungs?
- A. Removing carbon dioxide from the blood
- B. Exchanging oxygen and carbon dioxide
- C. Transporting oxygen to the bloodstream
- D. Filtering blood
Correct Answer: B
Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.
Which brain part is responsible for regulating heart rate and blood pressure?
- A. Cerebellum
- B. Medulla oblongata
- C. Hypothalamus
- D. Pons
Correct Answer: B
Rationale: The medulla oblongata, situated in the brainstem, plays a crucial role in controlling essential functions like heart rate, blood pressure, and breathing. It contains vital cardiovascular and respiratory centers, making it the correct choice for the regulation of heart rate and blood pressure. The cerebellum is primarily involved in coordinating movement and balance, not in regulating heart rate and blood pressure. The hypothalamus is responsible for maintaining homeostasis, regulating body temperature, hunger, and thirst, but not specifically heart rate and blood pressure. The pons is involved in functions like sleep, respiration, and bladder control, not primarily in regulating heart rate and blood pressure.
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.