Nokea
How do vaccines primarily function within the body?
- A. Creating a physical barrier against pathogens
- B. Triggering an inflammatory response
- C. Developing immunological memory to a specific pathogen
- D. Activating phagocytes to engulf pathogens
Correct Answer: C
Rationale: Vaccines primarily function by stimulating the immune system to develop immunological memory to a specific pathogen. When a vaccine is administered, it exposes the immune system to a harmless version of a pathogen or a piece of it. This exposure triggers the immune response, leading to the production of antibodies and memory cells specific to that pathogen. Choice A is incorrect because vaccines do not create a physical barrier; rather, they prepare the immune system to recognize and fight specific pathogens. Choice B is incorrect as vaccines do trigger an immune response, but the primary goal is to create memory rather than inflammation. Choice D is incorrect as vaccines do not directly activate phagocytes; instead, they stimulate the immune system to generate a targeted response against a particular pathogen.
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What does the innate immune system provide?
- A. Nonspecific, immediate defense against pathogens
- B. Specific, long-term immune response through memory cells
- C. Both (a) and (b)
- D. Neither (a) nor (b)
Correct Answer: A
Rationale: The correct answer is A. The innate immune system provides nonspecific, immediate defense against pathogens. It is the body's first line of defense in responding to infections and does not involve memory cells or specific long-term immune responses like the adaptive immune system. Choice B is incorrect because specific, long-term immune responses through memory cells are characteristics of the adaptive immune system, not the innate immune system. Choice C is incorrect because the innate immune system does not provide specific, long-term immune responses. Choice D is incorrect because the innate immune system does provide an immediate defense against pathogens.
Which muscular chamber of the heart receives blood from the body and pumps it to the lungs?
- A. Right atrium
- B. Left atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: A
Rationale: The correct answer is the right atrium. The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava. It then pumps this deoxygenated blood to the lungs via the pulmonary artery for oxygenation. The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle. The right ventricle receives oxygen-poor blood from the right atrium and pumps it to the lungs. The left ventricle receives oxygenated blood from the left atrium and pumps it to the rest of the body.
What are the moon-shaped white structures at the base of fingernails called?
- A. Lunulae
- B. Cuticle
- C. Hyponychium
- D. Matrix
Correct Answer: A
Rationale: The correct answer is A: Lunulae. The moon-shaped white structures at the base of fingernails are known as lunulae. They are most prominent on the thumb and are situated at the base of the nail matrix. The lunula is the visible part of the nail matrix, which is responsible for generating new nail cells. Choice B, Cuticle, is incorrect as it refers to the thin layer of skin at the base of the nail plate. Choice C, Hyponychium, is incorrect as it is the skin that lies beneath the free edge of the nail. Choice D, Matrix, is incorrect as it is the area where the nail is formed, located under the cuticle.
What is the term for a substance that can act as both a proton donor and a proton acceptor?
- A. Acid
- B. Base
- C. Amphiprotic
- D. Neutral
Correct Answer: C
Rationale: Amphiprotic substances are those that can both donate and accept protons. They possess characteristics of both acids and bases, making them capable of acting as proton donors and proton acceptors. Choices A and B represent substances that are specific to either donating or accepting protons. Choice D does not describe a substance's ability to donate or accept protons since neutrality does not inherently involve proton donation or acceptance.
What are the three main types of muscle tissue in the human body?
- A. Smooth, cardiac, and voluntary skeletal
- B. Smooth, skeletal, and involuntary cardiac
- C. Voluntary smooth, cardiac, and skeletal
- D. Striated, non-striated, and epithelial
Correct Answer: A
Rationale: The three main types of muscle tissue in the human body are smooth muscle (involuntary), cardiac muscle (involuntary), and voluntary skeletal muscle. Smooth muscle is found in the walls of hollow organs, cardiac muscle is found in the heart, and skeletal muscle is attached to bones and is under voluntary control. Option A correctly identifies these three main types of muscle tissue in the human body. Choice B is incorrect because it lists skeletal muscle as involuntary, which is not accurate. Choice C is incorrect because it lists voluntary smooth muscle, which does not exist as smooth muscle is involuntary. Choice D is incorrect because it uses terms like striated, non-striated, and epithelial, which are not the main types of muscle tissue but rather descriptions related to muscle characteristics and location.