Nursing Elites

1. What is the first event to occur in a primary immune response?

• A. Macrophages phagocytose pathogens and present their antigens.
• B. Neutrophils aggregate and act as cytotoxic, nonspecific killers of pathogens.
• C. B lymphocytes make pathogen-specific antibodies.
• D. Helper T cells secrete interleukins to activate pathogen-fighting cells.

Correct answer: A

Rationale: The correct answer is A. The initial event in a primary immune response is the phagocytosis of pathogens by macrophages and the subsequent presentation of their antigens, which is crucial for initiating the adaptive immune response. Neutrophils (Choice B) are also involved in the innate immune response, but they typically respond after macrophages. B lymphocytes (Choice C) produce antibodies later in the adaptive immune response, and Helper T cells (Choice D) help in coordinating the immune response but are not the first cells to act in a primary immune response.

2. How many tissue layers make up the uterus?

• A. One.
• B. Two.
• C. Three.
• D. Four.

Correct answer: C

Rationale: The correct answer is C, 'Three.' The uterus is composed of three tissue layers: the endometrium, myometrium, and perimetrium. The endometrium is the innermost layer that thickens during the menstrual cycle and sheds during menstruation or supports a developing embryo during pregnancy. The myometrium is the middle layer, consisting of muscle tissue that contracts during labor. The perimetrium is the outer layer that covers the uterus. These three layers work together to support the functions of the uterus, such as menstruation, pregnancy, and labor. Choices A, B, and D are incorrect because the uterus is not made up of just one or two layers but rather three distinct tissue layers.

3. Elements tend to gain or lose electrons to achieve stable electron configurations like those of noble gases. Their group number often indicates the number of electrons gained/lost and the resulting ionic charge, providing a good starting point for prediction.

• A. Ionic bonds involve electron sharing, while metallic bonds involve electron transfer.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: C

Rationale: Ionic bonds typically form between metals and non-metals, where one atom donates electrons (cation) and the other accepts electrons (anion). This results in the transfer of electrons. Metallic bonds, on the other hand, occur between metal atoms where electrons are shared among a sea of delocalized electrons, leading to the characteristic properties of metals like malleability and conductivity. Choice A is incorrect because ionic bonds involve electron transfer, not sharing. Choice B is incorrect as ionic bonds are strong, not weak, and are non-directional, while metallic bonds are strong and non-directional. Choice D is incorrect as ionic bonds do not form discrete molecules but rather a lattice structure, whereas metallic bonds form extended structures.

4. Which of the following describes a reflex arc?

• A. The storage and recall of memory
• B. The maintenance of visual and auditory acuity
• C. The autoregulation of heart rate and blood pressure
• D. A stimulus and response controlled by the spinal cord

Correct answer: D

Rationale: Choice D correctly describes a reflex arc. A reflex arc is a neural pathway that controls a reflex action. It involves a specific sequence of events that occur in response to a stimulus, which is rapidly and involuntarily processed by the spinal cord. The spinal cord coordinates the quick processing of sensory input and the generation of a motor response without involving the brain, allowing for rapid protective responses. Choices A, B, and C are incorrect because they do not accurately describe a reflex arc. A reflex arc is specifically related to the rapid and involuntary response to a stimulus through neural pathways involving the spinal cord, not memory storage, visual and auditory acuity maintenance, or heart rate and blood pressure autoregulation.

5. During swallowing, what is the role of the epiglottis, a small flap of cartilage located near the base of the tongue?

• A. Initiates the swallowing reflex
• B. Grinds food into smaller pieces
• C. Covers the trachea to prevent food aspiration
• D. Stores saliva for lubrication

Correct answer: C

Rationale: The epiglottis plays a crucial role during swallowing by covering the trachea to prevent food or liquid from entering the airway, which could lead to aspiration. By acting as a lid over the trachea, it ensures that food passes down the esophagus to the stomach, preventing it from entering the lungs. Choice A is incorrect as the swallowing reflex is a coordinated muscular action involving the tongue and throat muscles. Choice B is incorrect as grinding food into smaller pieces is primarily the function of the teeth and the initial stages of digestion. Choice D is incorrect as the storage of saliva for lubrication is not a function of the epiglottis, but rather involves salivary glands.

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