Which of the following is not a principal organ of the nervous system?
- A. Brain
- B. Thymus
- C. Ganglia
- D. Spinal cord
Correct Answer: B
Rationale: The correct answer is B. The thymus is not a principal organ of the nervous system; it is part of the immune system. The brain, spinal cord, and ganglia are principal organs of the nervous system. The brain is responsible for processing information, the spinal cord helps transmit signals between the brain and the rest of the body, and ganglia are clusters of nerve cells that support the nervous system's functions. Therefore, the thymus is the correct answer as it is not directly involved in nervous system functions.
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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 type of joint is found at the elbow?
- A. Ball and socket
- B. Hinge
- C. Pivot
- D. Saddle
Correct Answer: B
Rationale: The correct answer is B: Hinge. A hinge joint, such as the one found at the elbow, allows for movement primarily in one plane, enabling flexion and extension similar to the movement of a door hinge. This joint structure permits bending and straightening of the arm, controlling the range of motion in a specific direction. Choices A, C, and D are incorrect. A ball and socket joint allows for multi-axial movement like the hip joint, a pivot joint allows for rotation around an axis like the joint between the first and second cervical vertebrae, and a saddle joint allows for movement in two planes at right angles to each other like the joint at the base of the thumb.
Which part of the brain is involved in processing visual information?
- A. Temporal lobe
- B. Occipital lobe
- C. Parietal lobe
- D. Frontal lobe
Correct Answer: B
Rationale: The correct answer is B: Occipital lobe. The occipital lobe, situated at the back of the brain, is specifically responsible for processing visual information received from the eyes. It plays a crucial role in interpreting and making sense of visual stimuli, allowing individuals to perceive and comprehend the world around them. The Temporal lobe (Choice A) is involved in processing auditory information and memory, not visual processing. The Parietal lobe (Choice C) is responsible for processing sensory information from various parts of the body, but not specifically visual information. The Frontal lobe (Choice D) is involved in functions such as decision-making, problem-solving, and voluntary movement, but not processing visual stimuli.
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 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.
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