Nursing Elites

1. Which valve prevents blood from entering the left atrium when the ventricles contract?

• A. Pulmonary valve
• B. Tricuspid valve
• C. Mitral valve
• D. Aortic valve

Correct answer: C

Rationale: The correct answer is the mitral valve, also known as the bicuspid valve. The mitral valve prevents blood from flowing back into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the pulmonary valve is between the right ventricle and the pulmonary artery, and the aortic valve is situated between the left ventricle and the aorta. Therefore, choices A, B, and D are incorrect as they are not related to preventing blood from entering the left atrium during ventricular contraction.

2. Which vitamin plays a vital role in immune function?

• A. Vitamin A
• B. Vitamin B12
• C. Vitamin D
• D. Vitamin E

Correct answer: C

Rationale: Vitamin D is the correct answer. It plays a vital role in immune function by regulating the immune system and enhancing the pathogen-fighting effects of monocytes and macrophages. Deficiency in Vitamin D has been linked to increased susceptibility to infections and autoimmune diseases, highlighting its importance in maintaining a healthy immune response. Vitamin A (Choice A) is essential for vision and skin health but is not primarily known for its role in immune function. Vitamin B12 (Choice B) is important for red blood cell formation and neurological function, not specifically immune function. Vitamin E (Choice D) acts as an antioxidant and is beneficial for skin health and cell function, but it is not primarily associated with immune system support.

3. How do killer T cells recognize infected cells?

• A. The B cells flag the infected cells with amino acids.
• B. Tiny bits of the virus's RNA are left around the cell.
• C. Macrophages show up to help consume the infected cell.
• D. The T cells have receptors that recognize the proteins the virus leaves on the surface of the cell.

Correct answer: D

Rationale: Killer T cells recognize infected cells by detecting viral proteins displayed on the surface of these cells. The T cells possess receptors specifically designed to identify these viral proteins, allowing them to target and eliminate the infected cells. Choice A is incorrect because B cells are not directly involved in the recognition process of infected cells by killer T cells. Choice B is incorrect because tiny bits of the virus's RNA being left around the cell is not how killer T cells primarily recognize infected cells. Choice C is incorrect because while macrophages play a role in immune responses, they do not directly assist in the recognition of infected cells by killer T cells.

4. What is the main factor limiting population growth in K-strategists?

• A. Predation
• B. Availability of resources
• C. Competition
• D. Disease

Correct answer: B

Rationale: K-strategists are species with a low reproductive rate that invest more resources in raising fewer offspring. These species typically live in stable environments with limited resources. The main factor limiting population growth in K-strategists is the availability of resources such as food, shelter, and space. When resources are scarce, K-strategists may struggle to find enough to support their population size, leading to reduced reproductive success and population growth. While predation, competition, and disease can also impact population growth, the primary limiting factor for K-strategists is the availability of resources.

5. The adaptive immune system develops a targeted response to specific pathogens. What type of immune cell is responsible for producing antibodies?

• A. Natural killer cells
• B. Phagocytes
• C. Helper T cells
• D. B cells

Correct answer: D

Rationale: B cells are responsible for producing antibodies as part of the adaptive immune response. When activated by a specific antigen, B cells differentiate into plasma cells that secrete antibodies to target and neutralize pathogens. Natural killer cells are primarily involved in killing infected or cancerous cells, phagocytes engulf pathogens, and helper T cells assist in activating other immune cells. Therefore, the correct answer is B cells because they play a crucial role in antibody production, a key component of the adaptive immune response.

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